Digital Commons Network^™

Mechanisms Of Perceptual Learning Of Depth Discrimination In Random Dot Stereograms, Liat Gantz, Saumil S Patel, Susana T L Chung, Ronald S Harwerth

Faculty, Staff and Student Publications

Perceptual learning is a training induced improvement in performance. Mechanisms underlying the perceptual learning of depth discrimination in dynamic random dot stereograms were examined by assessing stereothresholds as a function of decorrelation. The inflection point of the decorrelation function was defined as the level of decorrelation corresponding to 1.4 times the threshold when decorrelation is 0%. In general, stereothresholds increased with increasing decorrelation. Following training, stereothresholds and standard errors of measurement decreased systematically for all tested decorrelation values. Post training decorrelation functions were reduced by a multiplicative constant (approximately 5), exhibiting changes in stereothresholds without changes in the inflection points. …

Ethnic/Racial Diversity, Maternal Stress, Lactation And Very Low Birthweight Infants, C Lau, N M. Hurst, E O. Smith, R J. Schanler

Faculty, Staff and Students Publications

OBJECTIVE: (1) To compare maternal characteristics and psychological stress profile among African-American, Caucasian and Hispanic mothers who delivered very low birthweight infants. (2) To investigate associations between psychosocial factors, frequency of milk expression, skin-to-skin holding (STS), and lactation performance, defined as maternal drive to express milk and milk volume. STUDY DESIGN: Self-reported psychological questionnaires were given every 2 weeks after delivery over 10 weeks. Milk expression frequency, STS, and socioeconomic variables were collected. RESULT: Infant birthweight, education, and milk expression frequency differed between groups. Trait anxiety, depression and parental stress in a neonatal intensive care unit (PSS:NICU) were similar. African-American …

Library Without Boundaries, Vol.20 (4) April - June 2007, Houston Academy Of Medicine-Texas Medical Center Library

Library Lines (1998-2009)

No abstract provided.

Library Survey, Vol.5 (3) May - June 2007, Houston Academy Of Medicine-Texas Medical Center Library

The Insider (2003-2008)

No abstract provided.

Different Dark Conformations Function In Color-Sensitive Photosignaling By The Sensory Rhodopsin I-Htri Complex, Jun Sasaki, Brian J Phillips, Xinpu Chen, Ned Van Eps, Ah-Lim Tsai, Wayne L Hubbell, John L Spudich

Faculty, Staff and Student Publications

The haloarchaeal phototaxis receptor sensory rhodopsin I (SRI) in complex with its transducer HtrI delivers an attractant signal from excitation with an orange photon and a repellent signal from a second near-UV photon excitation. Using a proteoliposome system with purified SRI in complex with its transducer HtrI, we identified by site-directed fluorescence labeling a site (Ser(155)) on SRI that is conformationally active in signal relay to HtrI. Using site-directed spin labeling of Ser(155)Cys with a nitroxide side chain, we detected a change in conformation following one-photon excitation such that the spin probe exhibits a splitting of the outer hyperfine extrema …

Importance Of The Ebp (Endocarditis- And Biofilm-Associated Pilus) Locus In The Pathogenesis Of Enterococcus Faecalis Ascending Urinary Tract Infection, Kavindra V Singh, Sreedhar R Nallapareddy, Barbara E Murray

Faculty, Staff and Student Publications

BACKGROUND: We recently demonstrated that the ubiquitous Enterococcus faecalis ebp (endocarditis- and biofilm-associated pilus) operon is important for biofilm formation and experimental endocarditis. Here, we assess its role in murine urinary tract infection (UTI) by use of wild-type E. faecalis OG1RF and its nonpiliated, ebpA allelic replacement mutant (TX5475).

METHODS: OG1RF and TX5475 were administered transurethrally either at an ~1 : 1 ratio (competition assay) or individually (monoinfection). Kidney pairs and urinary bladders were cultured 48 h after infection. These strains were also tested in a peritonitis model.

RESULTS: No differences were observed in the peritonitis model. In mixed UTIs, …

Short-Term Plasticity In A Computational Model Of The Tail-Withdrawal Circuit In Aplysia, Douglas A Baxter, John H Byrne

Faculty, Staff and Student Publications

The tail-withdrawal circuit of Aplysia provides a useful model system for investigating synaptic dynamics. Sensory neurons within the circuit manifest several forms of synaptic plasticity. Here, we developed a model of the circuit and investigated the ways in which depression (DEP) and potentiation (POT) contributed to information processing. DEP limited the amount of motor neuron activity that could be elicited by the monosynaptic pathway alone. POT within the monosynaptic pathway did not compensate for DEP. There was, however, a synergistic interaction between POT and the polysynaptic pathway. This synergism extended the dynamic range of the network, and the interplay between …

Agrobacterium Para/Mind-Like Virc1 Spatially Coordinates Early Conjugative Dna Transfer Reactions, Krishnamohan Atmakuri, Eric Cascales, Oliver T Burton, Lois M Banta, Peter J Christie

Faculty, Staff and Student Publications

Agrobacterium tumefaciens translocates T-DNA through a polar VirB/D4 type IV secretion (T4S) system. VirC1, a factor required for efficient T-DNA transfer, bears a deviant Walker A and other sequence motifs characteristic of ParA and MinD ATPases. Here, we show that VirC1 promotes conjugative T-DNA transfer by stimulating generation of multiple copies per cell of the T-DNA substrate (T-complex) through pairwise interactions with the processing factors VirD2 relaxase, VirC2, and VirD1. VirC1 also associates with the polar membrane and recruits T-complexes to cell poles, the site of VirB/D4 T4S machine assembly. VirC1 Walker A mutations abrogate T-complex generation and polar recruitment, …

Dynamics Of A Minimal Model Of Interlocked Positive And Negative Feedback Loops Of Transcriptional Regulation By Camp-Response Element Binding Proteins, Hao Song, Paul Smolen, Evyatar Av-Ron, Douglas A Baxter, John H Byrne

Faculty, Staff and Student Publications

cAMP-response element binding (CREB) proteins are involved in transcriptional regulation in a number of cellular processes (e.g., neural plasticity and circadian rhythms). The CREB family contains activators and repressors that may interact through positive and negative feedback loops. These loops can be generated by auto- and cross-regulation of expression of CREB proteins, via CRE elements in or near their genes. Experiments suggest that such feedback loops may operate in several systems (e.g., Aplysia and rat). To understand the functional implications of such feedback loops, which are interlocked via cross-regulation of transcription, a minimal model with a positive and negative loop …

Chronic Administration Of Methylphenidate Produces Neurophysiological And Behavioral Sensitization, Pamela B Yang, Alan C Swann, Nachum Dafny

Faculty, Staff and Student Publications

The electrophysiological properties of acute and chronic methylphenidate (MPD) on neurons of the prefrontal cortex (PFC) and caudate nucleus (CN) have not been studied in awake, freely behaving animals. The present study was designed to investigate the dose-response effects of MPD on sensory evoked potentials recorded from the PFC and CN in freely behaving rats previously implanted with permanent electrodes, as well as their behavioral (locomotor) activities. On experimental day 1, locomotor behavior of rats was recorded for 2 h post-saline injection, and sensory evoked field potentials were recorded before and after saline and 0.6, 2.5, and 10 mg/kg, i.p., …

Insider Express, Houston Academy Of Medicine-Texas Medical Center Library

Insider Express (2003-2013)

No abstract provided.

An Interdisciplinary Approach To A Dental Information Technology Course, Alan E. Levine Phd, Med, Richard D. Bebermeyer Dds, Jung-Wei Chen Dds, Dell Davis Mls

Advances in Teaching and Learning Day Abstracts

Purpose: To develop an interdisciplinary course to teach dental students about evidence-based dentistry, development of search strategies, critical appraisal of literature, and dental informatics. [See PDF for complete abstract]

Use Of An Online Discussion Board To Improve Diagnostic Skills, Terry A. Rustin Md

Advances in Teaching and Learning Day Abstracts

We have used the “Discussion Board” feature of an online classroom application (Blackboard) to present diagnostic questions for our advanced practice nursing students in their course on differential diagnosis. [See PDF for complete abstract]

The Prevalence And Focus Of Medical Education Fellowships Across North America, Nancy S. Searle Edd, Britta M. Thompson Phd

Advances in Teaching and Learning Day Abstracts

Medical institutions have established medical education fellowships to equip faculty to meet the challenge of constant educational change and to empower faculty to assume programmatic leadership roles in medical education. The purpose of this study was to determine the prevalence and focus of these programs. [See PDF for complete abstract]

Tailored Instructional Methods For Students With Diverse Levels Of Computer Knowledge And Skills, Yuh-Fong Hong Phd

Advances in Teaching and Learning Day Abstracts

The purpose of this online course is to ensure new nursing graduate students know how to use computer technologies required to complete academic and research activities. Powerful computers, high speed internet, digitalized resources and databases are widely available in educational institutes. New renovation and updates are being released at faster pace than ever. All these developments are necessary for a student to utilize computer programs and synthesize large amount of data in a limited time for any given academic research project. [See PDF for complete abstract]

From Caregiver To Computer Geek: The Design Of A Web Resource For Novice Clinical Informaticians, Stephanie K. Wheeler Rn, Bsn, Cynthia L. Phelps Phd, Irmgard U. Willcockson Phd, Robert W. Vogler Rn, Dsn

Advances in Teaching and Learning Day Abstracts

Introduction: Throughout the United States, there are massive initiatives in place to reform healthcare through the implementation of electronic health records. The goals are to improve patient care through improved access to records, the improvement of business and reimbursement processes, streamlining of clinician workflows for increased efficiency, and reducing the variability in the delivery of patient care. [See PDF for complete abstract]

Online Catalog System Upgrade, Vol.5 (2) March - April 2007, Houston Academy Of Medicine-Texas Medical Center Library

The Insider (2003-2008)

No abstract provided.

Insider Express, Houston Academy Of Medicine-Texas Medical Center Library

Insider Express (2003-2013)

No abstract provided.

Direct Visualization Of The Putative Portal In The Kaposi's Sarcoma-Associated Herpesvirus Capsid By Cryoelectron Tomography, Binbin Deng, Christine M O'Connor, Dean H Kedes, Z Hong Zhou

Faculty, Staff and Student Publications

Genetic and biochemical studies have suggested the existence of a bacteriophage-like, DNA-packaging/ejecting portal complex in herpesviruses capsids, but its arrangement remained unknown. Here, we report the first visualization of a unique vertex in the Kaposi's sarcoma-associated herpesvirus (KSHV) capsid by cryoelectron tomography, thus providing direct structural evidence for the existence of a portal complex in a gammaherpesvirus. This putative KSHV portal is an internally localized, umbilicated structure and lacks all of the external machineries characteristic of portals in DNA bacteriophages.

Radiation Injury Is A Potentially Serious Complication To Fluoroscopically-Guided Complex Interventions, Lk Wagner

Faculty, Staff and Student Publications

Radiation-induced injury to skin is an infrequent but potentially serious complication to complex fluoroscopically-guided interventional procedures. Due to a lack of experience with such injuries, the medical community has found fluoroscopically-induced injuries difficult to diagnose. Injuries have occurred globally in many countries. Serious injuries most frequently occur on the back but have also occurred on the neck, buttocks and anterior of the chest. Severities of injuries range from skin rashes and epilation to necrosis of the skin and its underlying structures. This article reviews the characteristics of these injuries and some actions that can be taken to reduce their likelihood …

Interaction Between Cell Division Proteins Ftse And Ftsz, Brian D Corbin, Yipeng Wang, Tushar K Beuria, William Margolin

Faculty, Staff and Student Publications

FtsE and FtsX, which are widely conserved homologs of ABC transporters and interact with each other, have important but unknown functions in bacterial cell division. Coimmunoprecipitation of Escherichia coli cell extracts revealed that a functional FLAG-tagged version of FtsE, the putative ATP-binding component, interacts with FtsZ, the bacterial tubulin homolog required to assemble the cytokinetic Z ring and recruit the components of the divisome. This interaction is independent of FtsX, the predicted membrane component of the ABC transporter, which has been shown previously to interact with FtsE. The interaction also occurred independently of FtsA or ZipA, two other E. coli …

Crystal Structure Of The Anabaena Sensory Rhodopsin Transducer, Lutz Vogeley, Vishwa D Trivedi, Oleg A Sineshchekov, Elena N Spudich, John L Spudich, Hartmut Luecke

Faculty, Staff and Student Publications

We present crystal structures of the Anabaena sensory rhodopsin transducer (ASRT), a soluble cytoplasmic protein that interacts with the first structurally characterized eubacterial retinylidene photoreceptor Anabaena sensory rhodopsin (ASR). Four crystal structures of ASRT from three different spacegroups were obtained, in all of which ASRT is present as a planar (C4) tetramer, consistent with our characterization of ASRT as a tetramer in solution. The ASRT tetramer is tightly packed, with large interfaces where the well-structured beta-sandwich portion of the monomers provides the bulk of the tetramer-forming interactions, and forms a flat, stable surface on one side of the tetramer (the …

Laser-Induced Transient Grating Analysis Of Dynamics Of Interaction Between Sensory Rhodopsin Ii D75n And The Htrii Transducer, Keiichi Inoue, Jun Sasaki, John L Spudich, Masahide Terazima

Faculty, Staff and Student Publications

The interaction between sensory rhodopsin II (SRII) and its transducer HtrII was studied by the time-resolved laser-induced transient grating method using the D75N mutant of SRII, which exhibits minimal visible light absorption changes during its photocycle, but mediates normal phototaxis responses. Flash-induced transient absorption spectra of transducer-free D75N and D75N joined to 120 amino-acid residues of the N-terminal part of the SRII transducer protein HtrII (DeltaHtrII) showed only one spectrally distinct K-like intermediate in their photocycles, but the transient grating method resolved four intermediates (K(1)-K(4)) distinct in their volumes. D75N bound to HtrII exhibited one additional slower kinetic species, which …

2007 State Of The Journals Report, Vol.20 (3) January - March 2007, Houston Academy Of Medicine-Texas Medical Center Library

Library Lines (1998-2009)

No abstract provided.

Aldosterone-Induced Sgk1 Relieves Dot1a-Af9-Mediated Transcriptional Repression Of Epithelial Na+ Channel Alpha, Wenzheng Zhang, Xuefeng Xia, Mary Rose Reisenauer, Timo Rieg, Florian Lang, Dietmar Kuhl, Volker Vallon, Bruce C Kone

Faculty, Staff and Student Publications

Aldosterone plays a major role in the regulation of salt balance and the pathophysiology of cardiovascular and renal diseases. Many aldosterone-regulated genes--including that encoding the epithelial Na+ channel (ENaC), a key arbiter of Na+ transport in the kidney and other epithelia--have been identified, but the mechanisms by which the hormone modifies chromatin structure and thus transcription remain unknown. We previously described the basal repression of ENaCalpha by a complex containing the histone H3 Lys79 methyltransferase disruptor of telomeric silencing alternative splice variant a (Dot1a) and the putative transcription factor ALL1-fused gene from chromosome 9 (Af9) as well as the release …

Severe Aortic And Arterial Aneurysms Associated With A Tgfbr2 Mutation, Scott A Lemaire, Hariyadarshi Pannu, Van Tran-Fadulu, Stacey A Carter, Joseph S Coselli, Dianna M Milewicz

Faculty, Staff and Student Publications

BACKGROUND: A 24-year-old man presented with previously diagnosed Marfan's syndrome. Since the age of 9 years, he had undergone eight cardiovascular procedures to treat rapidly progressive aneurysms, dissection and tortuous vascular disease involving the aortic root and arch, the thoracoabdominal aorta, and brachiocephalic, vertebral, internal thoracic and superior mesenteric arteries. Throughout this extensive series of cardiovascular surgical repairs, he recovered without stroke, paraplegia or renal impairment.

INVESTIGATIONS: CT scans, arteriogram, genetic mutation screening of transforming growth factor beta receptors 1 and 2.

DIAGNOSIS: Diffuse and rapidly progressing vascular disease in a patient who met the diagnostic criteria for Marfan's syndrome, …

Imaging Of Pulmonary Embolism And T-Pa Therapy Effects Using Mdct And Liposomal Iohexol Blood Pool Agent: Preliminary Results In A Rabbit Model, Stephen J Burke, Ananth Annapragada, Eric A Hoffman, Emmanuel Chen, Ketan B Ghaghada, Jered Sieren, Edwin J R Van Beek

Faculty, Staff and Student Publications

RATIONALE AND OBJECTIVES: Polyethylene glycol-coated liposomal blood pool contrast agents maintain contrast enhancement over several hours. This study aimed to evaluate (long-term) imaging of pulmonary arteries, comparing conventional iodinated contrast with a liposomal blood pool contrast agent. Also, visualization of the (real-time) therapeutic effects of tissue plasminogen activator (t-PA) on pulmonary embolism (PE) was attempted. MATERIALS AND METHODS: Six rabbits (weight approximately 4 kg) had autologous blood clots injected through the superior vena cava. Imaging was performed using conventional contrast (iohexol, 350 mg I/ml; GE HealthCare, Princeton, NJ) at a dose of 1400 mg I per animal, and after wash-out, …

A Day In The Life Of Pubmed: Analysis Of A Typical Day's Query Log, Jorge R Herskovic, Len Y Tanaka, William Hersh, Elmer V Bernstam

Faculty, Staff and Student Publications

OBJECTIVE: To characterize PubMed usage over a typical day and compare it to previous studies of user behavior on Web search engines. DESIGN: We performed a lexical and semantic analysis of 2,689,166 queries issued on PubMed over 24 consecutive hours on a typical day. MEASUREMENTS: We measured the number of queries, number of distinct users, queries per user, terms per query, common terms, Boolean operator use, common phrases, result set size, MeSH categories, used semantic measurements to group queries into sessions, and studied the addition and removal of terms from consecutive queries to gauge search strategies. RESULTS: The size of …

Traumatic Brain Injury Stimulates Hippocampal Catechol-O-Methyl Transferase Expression In Microglia, John B Redell, Pramod K Dash

Faculty, Staff and Student Publications

Outcome following traumatic brain injury (TBI) is in large part determined by the combined action of multiple processes. In order to better understand the response of the central nervous system to injury, we utilized an antibody array to simultaneously screen 507 proteins for altered expression in the injured hippocampus, a structure critical for memory formation. Array analysis indicated 41 candidate proteins have altered expression levels 24h after TBI. Of particular interest was catechol-O-methyl transferase (COMT), an enzyme involved in metabolizing catecholamines released following neuronal activity. Altered catecholamine signaling has been observed after brain injury, and may contribute to the cognitive …

Library Online Catalog Relocated, Vol.5 (1) January - February 2007, Houston Academy Of Medicine-Texas Medical Center Library

The Insider (2003-2008)

No abstract provided.