48 results on '"Gonzalez, Eric"'
Search Results
2. Development and evaluation of a decision support mobile application for cotton irrigation management
- Author
-
Ale, Srinivasulu, Su, Qiong, Singh, Jasdeep, Himanshu, Sushil, Fan, Yubing, Stoker, Blake, Gonzalez, Eric, Sapkota, Bala Ram, Adams, Curtis, Biggers, Keith, Kimura, Emi, and Wall, James
- Published
- 2023
- Full Text
- View/download PDF
3. Digital survey of mental health, associated psychosocial, and work factors in medical specialty residents in the Guadalajara metropolitan area
- Author
-
Lopez, Jesus Alejandro Aldana, Gonzalez, Eric Foulkes, Palomera, Jose Fernando Ojeda, Huerta, Jaime Carmona, and Fernandez, Martin Acosta
- Published
- 2021
- Full Text
- View/download PDF
4. WRN inhibition leads to its chromatin-associated degradation via the PIAS4-RNF4-p97/VCP axis.
- Author
-
Rodríguez Pérez, Fernando, Natwick, Dean, Schiff, Lauren, McSwiggen, David, Heckert, Alec, Huey, Melina, Morrison, Huntly, Loo, Mandy, Miranda, Rafael G., Filbin, John, Ortega, Jose, Van Buren, Kayla, Murnock, Danny, Tao, Arnold, Butler, Renee, Cheng, Kylie, Tarvestad, William, Zhang, Zhengjian, Gonzalez, Eric, and Miller, Rand M.
- Subjects
DRUG discovery ,SINGLE molecules ,SMALL molecules ,CANCER cells ,LABORATORY mice - Abstract
Synthetic lethality provides an attractive strategy for developing targeted cancer therapies. For example, cancer cells with high levels of microsatellite instability (MSI-H) are dependent on the Werner (WRN) helicase for survival. However, the mechanisms that regulate WRN spatiotemporal dynamics remain poorly understood. Here, we used single-molecule tracking (SMT) in combination with a WRN inhibitor to examine WRN dynamics within the nuclei of living cancer cells. WRN inhibition traps the helicase on chromatin, requiring p97/VCP for extraction and proteasomal degradation in a MSI-H dependent manner. Using a phenotypic screen, we identify the PIAS4-RNF4 axis as the pathway responsible for WRN degradation. Finally, we show that co-inhibition of WRN and SUMOylation has an additive toxic effect in MSI-H cells and confirm the in vivo activity of WRN inhibition using an MSI-H mouse xenograft model. This work elucidates a regulatory mechanism for WRN that may facilitate identification of new therapeutic modalities, and highlights the use of SMT as a tool for drug discovery and mechanism-of-action studies. New optical methods for investigating the activity of small molecules in cells may facilitate development of anticancer therapeutics. Here, the authors use a super-resolution optical platform and single molecule tracking to gain insight into WRN regulation in cancer. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
5. THE DEATHS OF MIGRANT WORKERS IN QATAR'S 200 BILLION DOLLAR PROCUREMENTS TO HOST THE 2022 WORLD CUP HAVE IGNITED A CALL FOR CHANGE.
- Author
-
Gonzalez, Eric
- Subjects
- *
MIGRANT labor , *GOVERNMENT purchasing , *LABOR laws , *FIFA World Cup (2022 : Qatar) , *HOSTING of sporting events - Abstract
Qatar is a Middle Eastern country that attracted the international spotlight for its improbable award of the 2022 World Cup back in 2010. This was an historic event in the history of the World Cup because it was the first time a Middle Eastern country was awarded the right to host the games. However, this tremendous event has been overshadowed by stories of abuse of migrant workers tasked with building the infrastructure for this momentous event. Due in part to FIFA’s history of corruption and Qatar’s procurement process of employing companies without investigating their employment practices, a sporting event that was meant to be enjoyed by millions of people is shrouded in disgust and death. Without the intervention of FIFA’s member nations enforcing more stringent practices to avoid the atrocities of Qatar and World Cups before it, more people will continue to be taken advantage of. Introducing an independent governing body that is separate from FIFA would alleviate some of the problems facing the procurement issues that plagued Qatar by allowing independent investigators to determine whether a host country has sufficiently developed and mature procurement practices to build infrastructure for the greatest tournament in the world. [ABSTRACT FROM AUTHOR]
- Published
- 2024
6. Randomized Controlled Trial to Assess the Impact of Intraurethral Lidocaine on Urodynamic Voiding Parameters
- Author
-
Kisby, Cassandra K., Gonzalez, Eric J., Visco, Anthony G., Amundsen, Cindy L., and Grill, Warren M.
- Published
- 2019
- Full Text
- View/download PDF
7. Axion misalignment driven to the hilltop
- Author
-
Co, Raymond T., Gonzalez, Eric, and Harigaya, Keisuke
- Published
- 2019
- Full Text
- View/download PDF
8. Axion misalignment driven to the bottom
- Author
-
Co, Raymond T., Gonzalez, Eric, and Harigaya, Keisuke
- Published
- 2019
- Full Text
- View/download PDF
9. UNA PROPUESTA DE CLASIFICACIÓN DE LA CLASE MAGISTRAL IMPARTIDA EN LA FACULTAD DE DERECHO / A PROPOSED CLASSIFICATION OF THE MASTER CLASS AT THE FACULTY OF LAW
- Author
-
Rosas, María Francisca Elgueta and González, Eric Eduardo Palma
- Published
- 2014
10. « Cash still rules »: La représentation du succès dans le rap
- Author
-
Gonzalez, Éric
- Published
- 2005
11. Social Determinants of Health and Child Maltreatment Prevention: The Family Success Network Pilot.
- Author
-
Johnson-Motoyama, Michelle, Moon, Deborah, Rolock, Nancy, Crampton, David, Nichols, C. Bailey, Haran, Hanna, Zhang, Yiran, Motoyama, Yasuyuki, Gonzalez, Eric, and Sillaman, Nicole
- Published
- 2022
- Full Text
- View/download PDF
12. RFEA: Ella Fitzgerald: « Flying Home »
- Author
-
Gonzalez, Éric
- Published
- 2004
13. In and Along the Mississippi: The Motif of Music in Joel and Ethan Coen's "O Brother, Where Art Thou?" and Jim Jarmusch's "Mystery Train"
- Author
-
Gonzalez, Eric
- Published
- 2003
14. Le jazz: modernité, modernisme, identité
- Author
-
Gonzalez, Éric
- Published
- 2001
15. Buxarrais M. R. Vilafranca I. Una mirada femenina de la educación moral / A feminine view of moral education
- Author
-
González, Eric Ortega
- Published
- 2019
16. Parasporins from a Caribbean Island: Evidence for a Globally Dispersed Bacillus thuringiensis Strain
- Author
-
Gonzalez, Eric, Granados, Jose C., Short, John D., Ammons, David R., and Rampersad, Joanne
- Published
- 2011
- Full Text
- View/download PDF
17. Identification of Selective CYP3A7 and CYP3A4 Substrates and Inhibitors Using a High-Throughput Screening Platform.
- Author
-
Kabir, Md, Padilha, Elias C., Shah, Pranav, Huang, Ruili, Sakamuru, Srilatha, Gonzalez, Eric, Lin Ye, Xin Hu, Henderson, Mark J., Menghang Xia, and Xin Xu
- Subjects
CYTOCHROME P-450 CYP3A ,HIGH throughput screening (Drug development) ,DRUG metabolism ,DRUG interactions ,MOLECULAR docking - Abstract
Cytochrome P450 (CYP) 3A7 is one of the major xenobiotic metabolizing enzymes in human embryonic, fetal, and newborn liver. CYP3A7 expression has also been observed in a subset of the adult population, including pregnant women, as well as in various cancer patients. The characterization of CYP3A7 is not as extensive as other CYPs, and health authorities have yet to provide guidance towards DDI assessment. To identify potential CYP3A7-specific molecules, we used a P450-Glo CYP3A7 enzyme assay to screen a library of ~5,000 compounds, including FDA-approved drugs and drug-like molecules, and compared these screening data with that from a P450-Glo CYP3A4 assay. Additionally, a subset of 1,000 randomly selected compounds were tested in a metabolic stability assay. By combining the data from the qHTS P450-Glo and metabolic stability assays, we identified several chemical features important for CYP3A7 selectivity. Halometasone was chosen for further evaluation as a potential CYP3A7-selective inhibitor using molecular docking. From the metabolic stability assay, we identified twenty-two CYP3A7-selective substrates over CYP3A4 in supersome setting. Our data shows that CYP3A7 has ligand promiscuity, much like CYP3A4. Furthermore, we have established a large, high-quality dataset that can be used in predictive modeling for future drug metabolism and interaction studies. [ABSTRACT FROM AUTHOR]
- Published
- 2022
- Full Text
- View/download PDF
18. Augmenting Perceived Softness of Haptic Proxy Objects Through Transient Vibration and Visuo-Haptic Illusion in Virtual Reality.
- Author
-
Choi, Inrak, Zhao, Yiwei, Gonzalez, Eric J., and Follmer, Sean
- Subjects
HAPTIC devices ,VIRTUAL reality ,COMPUTER graphics ,TRANSIENT analysis - Abstract
In this article, we investigate the effects of active transient vibration and visuo-haptic illusion to augment the perceived softness of haptic proxy objects. We introduce a system combining active transient vibration at the fingertip with visuo-haptic illusions. In our hand-held device, a voice coil actuator transmits active transient vibrations to the index fingertip, while a force sensor measures the force applied on passive proxy objects to create visuo-haptic illusions in virtual reality. We conducted three user studies to understand both the vibrotactile effect and its combined effect with visuo-haptic illusions. A preliminary study confirmed that active transient vibrations can intuitively alter the perceived softness of a proxy object. Our first study demonstrated that those same active transient vibrations can generate different perceptions of softness depending on the material of the proxy object used. In our second study, we evaluated the combination of active transient vibration and visuo-haptic illusion, and found that both significantly influence perceived softness, with with the visuo-haptic effect being dominant. Our third study further investigated the vibrotactile effect while controlling for the visuo-haptic illusion. The combination of these two methods allows users to effectively perceive various levels of softness when interacting with haptic proxy objects. [ABSTRACT FROM AUTHOR]
- Published
- 2021
- Full Text
- View/download PDF
19. Dysfunctional voiding behavior and impaired muscle contractility in a rat model of detrusor underactivity.
- Author
-
Gonzalez, Eric J., Odom, Michael R., Hannan, Johanna L., and Grill, Warren M.
- Subjects
ANIMAL disease models ,URINATION disorders ,ELECTRIC stimulation ,URETHRA ,PATHOLOGICAL physiology ,ELECTRIC fields ,LABORATORY rats - Abstract
Aims: Detrusor underactivity (DU) is an understudied health concern with inadequate clinical management. The pathophysiology of DU is unclear, and current therapies fail to improve symptoms. The current studies characterized voiding function and contractility of bladder and urethral tissues in a novel rat model of DU. Methods: Female obese prone (OP) and obese resistant (OR) rats were fed a 60 kcal% fat diet at 8 weeks old. A subset of rats (n = 4/strain) underwent uroflowmetry biweekly for 18 weeks in metabolic cages. At 40–56 weeks old, rats (n = 9–10/strain) underwent instrumented cystometry under urethane anesthesia. Following cystometry, bladder and urethral tissues (n = 8–9/strain) were harvested for in vitro assessments of contractility in response to carbachol, electric field stimulation, atropine, alpha, beta‐methylene ATP, and caffeine. Results: OP rats exhibited increased urinary frequency (p = 0.0031), decreased voided volume (p = 0.0093), and urine flow rate (p = 0.0064) compared to OR rats during uroflowmetry. Bethanechol (10 mg/kg) did not alter uroflowmetry parameters. During cystometry, OP rats exhibited decreased bladder emptying efficiency (p < 0.0001), decreased pressure to generate a void (p < 0.0001), and increased EUS activity during filling (p = 0.0011). Bladder contractility was decreased in OP rats when exposed to carbachol (p < 0.0003) and ATP (p = 0.0004), whereas middle urethral contractility was increased when exposed to carbachol (p = 0.0014), EFS (p = 0.0289), and caffeine (p = 0.0031). Conclusion: Impaired cholinergic and purinergic signaling in the bladder may contribute to poor voiding function in OP rats. In addition, increased urethral activity may engage a guarding reflex to augment continence and exacerbate incomplete emptying. [ABSTRACT FROM AUTHOR]
- Published
- 2021
- Full Text
- View/download PDF
20. Cooled-tip vs. 8 mm-tip catheter for circumferential pulmonary vein ablation: comparison of efficacy, safety, and lesion extension
- Author
-
Matiello, Maria, Mont, Lluis, Tamborero, David, Berruezo, Antonio, Benito, Begoña, Gonzalez, Eric, and Brugada, Josep
- Published
- 2008
21. Advances in the study of drug metabolism – symposium report of the 12th Meeting of the International Society for the Study of Xenobiotics (ISSX).
- Author
-
Russell, Laura E., Schleiff, Mary Alexandra, Gonzalez, Eric, Bart, Aaron G., Broccatelli, Fabio, Hartman, Jessica H., Humphreys, W. Griffith, Lauschke, Volker M., Martin, Iain, Nwabufo, Chukwunonso, Prasad, Bhagwat, Scott, Emily E., Segall, Matthew, Takahashi, Ryan, Taub, Mitchell E., and Sodhi, Jasleen K.
- Subjects
XENOBIOTICS ,DRUG metabolism ,QUANTUM mechanics ,CHEMICAL synthesis ,NATURAL products ,CONFERENCES & conventions - Abstract
The 12th International Society for the Study of Xenobiotics (ISSX) meeting, held in Portland, OR, USA from July 28 to 31, 2019, was attended by diverse members of the pharmaceutical sciences community. The ISSX New Investigators Group provides learning and professional growth opportunities for student and early career members of ISSX. To share meeting content with those who were unable to attend, the ISSX New Investigators herein elected to highlight the "Advances in the Study of Drug Metabolism" symposium, as it engaged attendees with diverse backgrounds. This session covered a wide range of current topics in drug metabolism research including predicting sites and routes of metabolism, metabolite identification, ligand docking, and medicinal and natural products chemistry, and highlighted approaches complemented by computational modeling. In silico tools have been increasingly applied in both academic and industrial settings, alongside traditional and evolving in vitro techniques, to strengthen and streamline pharmaceutical research. Approaches such as quantum mechanics simulations facilitate understanding of reaction energetics toward prediction of routes and sites of drug metabolism. Furthermore, in tandem with crystallographic and orthogonal wet lab techniques for structural validation of drug metabolizing enzymes, in silico models can aid understanding of substrate recognition by particular enzymes, identify metabolic soft spots and predict toxic metabolites for improved molecular design. Of note, integration of chemical synthesis and biosynthesis using natural products remains an important approach for identifying new chemical scaffolds in drug discovery. These subjects, compiled by the symposium organizers, presenters, and the ISSX New Investigators Group, are discussed in this review. [ABSTRACT FROM AUTHOR]
- Published
- 2020
- Full Text
- View/download PDF
22. Randomized Controlled Trial to Assess the Impact of High Concentration Intraurethral Lidocaine on Urodynamic Voiding Parameters.
- Author
-
McKee, Dana C., Gonzalez, Eric J., Amundsen, Cindy L., and Grill, Warren M.
- Subjects
- *
RANDOMIZED controlled trials , *LIDOCAINE , *CYSTOMETRY , *LOCAL anesthesia , *COMPARATIVE studies , *LOCAL anesthetics , *RESEARCH methodology , *MEDICAL cooperation , *PAIN , *RESEARCH , *RESEARCH funding , *CUTANEOUS therapeutics , *URETHRA , *URINARY catheterization , *URINATION , *URODYNAMICS , *EVALUATION research , *BLIND experiment , *PHARMACODYNAMICS - Abstract
Objective: To assess whether intraurethral anesthesia decreased voiding efficiency (VE), reduced catheterization pain, and impacted urodynamic parameters in healthy adult females.Methods: In a randomized, double-blind, placebo-controlled trial, participants received two 5 mL doses of either intraurethral aqueous gel or 4% lidocaine gel. The primary outcome was VE during randomized condition uroflow, defined as voided volume/(voided volume + residual volume). The secondary outcomes were pain during catheterization and to confirm previously reported pressure-flow changes. A sample size of 10 per group was planned to detect a clinically significant decrease in VE with a power (1-β) of 0.99.Results: From October to December 2018, 23 women were screened and 18 were randomized to receive placebo (n = 10) or lidocaine (n = 8). Baseline uroflow VE was similar between the placebo and lidocaine groups (88 ± 6.6% vs 91 ± 5.8%, P = .33). After study drug administration, the changes in VE (post-pre) were similar between placebo and lidocaine groups (-5.4 ± 14% vs 1.7 ± 6.4%, P = .21). Visual analog scores were similar following catheterizations (26.7 ± 12.8 mm vs 36.9 ± 26.8 mm, P = .34). The lidocaine group exhibited lower average flow rates per voided volume (0.04 ± 0.02 s-1 vs 0.02 ± 0.01 s-1, P = .04).Conclusion: Intraurethral administration of 4% lidocaine did not decrease VE compared to placebo and did not change pain scores following catheterization. In the lidocaine group, the average flow rate per voided volume was lower. The decrease in flow rate after local anesthesia to the urethra may indicate that urethral sensory feedback contributes to voiding in human micturition. [ABSTRACT FROM AUTHOR]- Published
- 2019
- Full Text
- View/download PDF
23. Infrared observation of linear GeC3 trapped in solid Ar.
- Author
-
Gonzalez, Eric, Rittby, C. M. L., and Graham, W. R. M.
- Subjects
- *
MOLECULES , *OPTOELECTRONICS , *DENSITY functionals , *SILICON carbide , *ISOTOPES , *FOURIER transform infrared spectroscopy - Abstract
Linear GeC3 has been synthesized and its vibrational spectrum observed for the first time. The cluster was detected by Fourier transform infrared spectroscopy when the products from the dual laser ablation of either a pair of carbon and germanium rods or a single, sintered germanium-carbon rod were trapped in solid Ar at ∼10 K. Comparison of 13C isotopic shift measurements with the predictions of density functional theory calculations at the B3LYP/cc-pVDZ level has resulted in the identification of the ν1(σ) and ν2(σ) modes of linear GeC3 at 1903.9 and 1279.6 cm-1, respectively. For the related group IV clusters, this result is in contrast to SiC3 for which two cyclic isomers have been observed but similar to C4 for which only the linear isomer has been observed spectroscopically. [ABSTRACT FROM AUTHOR]
- Published
- 2009
- Full Text
- View/download PDF
24. FTIR identification of the [v.sub.4]([[sigma].sub.[meu]]) and [v.sub.6]([[pi].sub.[meu]]) modes of linear Ge[C.sub.3]Ge trapped in solid Ar
- Author
-
Gonzalez, Eric, Rittby, C.M.L., and Graham, W.R.M.
- Subjects
Argon -- Chemical properties ,Density functionals -- Usage ,Fourier transform infrared spectroscopy -- Usage ,Germanium -- Chemical properties ,Germanium -- Spectra ,Chemicals, plastics and rubber industries - Published
- 2008
25. Design and Analysis of High-Resolution Electrostatic Adhesive Brakes Towards Static Refreshable 2.5D Tactile Shape Display.
- Author
-
Zhang, Kai, Gonzalez, Eric J., Guo, Jianglong, and Follmer, Sean
- Abstract
Tactile displays are haptic devices capable of rendering shape and texture information. Unsolved challenges in building tactile shape displays include their traditionally large form factors, low spatial resolution, and high costs. Using electrostatic adhesion to individually brake each pin and a single platform for global actuation, we developed a prototype static refreshable tactile shape display with high spatial resolution (1.7 mm pitch, 0.8 mm pin width; 4 mm pitch, 1.6 mm pin width), high resistance force (76.3 gf static-loading force per pin for 1.6 mm width) and low cost ($0.11 USD per pin for raw material). We present an analytical model of our electroadhesive brake mechanism and evaluate its maximum contact force and robustness in various conditions. To demonstrate the mechanism's potential, we built a static tactile shape display prototype with a $4\times 2$ array of pins controlled using electroadhesive brakes. To further increase maximsum contact force allowed by our device, we develop and evaluate a global mechanical clutch which can be engaged during user interaction. A user study is carried out to compare our static tactile shape display's performance with printed 2.5D tactile graphics in a shape recognition task, and comparable shape recognition rates and response times are observed. [ABSTRACT FROM AUTHOR]
- Published
- 2019
- Full Text
- View/download PDF
26. Sensory pudendal nerve stimulation increases bladder capacity through sympathetic mechanisms in cyclophosphamide‐induced cystitis rats.
- Author
-
Gonzalez, Eric J. and Grill, Warren M.
- Abstract
Aims: Interstitial cystitis and bladder pain syndrome is a prevalent health concern with inadequate treatments. Neuromodulation has emerged as a therapeutic option to treat patients refractory to standard care. The objective of this study was to determine the efficacy and mechanism(s) of sensory pudendal nerve stimulation on bladder function in cystitis rats. Methods: Female rats were administered saline (n = 8) or cyclophosphamide (CYP, 150 mg/kg IP, n = 16) and single‐trial cystometry experiments were conducted under urethane anesthesia 48 h after injection. Electrical stimulation (0.02‐0.22 mA, 10‐20 Hz) was delivered to the sensory branch of the pudendal nerve and its effect on the bladder and external urethral sphincter were measured. Stimulation trials were also conducted following bilateral hypogastric nerve transection (HGNT) or pharmacological inhibition of beta‐adrenergic receptors (propranolol, 1 mg/kg IV) to determine the mechanisms of bladder inhibition. Results: CYP‐induced cystitis decreased bladder capacity (P = 0.0352) and bladder compliance (P = 0.024) by up to 38% of control. Electrical stimulation of the sensory pudendal nerve increased bladder capacity (P < 0.0001) in control and CYP rats by up to 51‐52% of their respective baselines. HGNT did not influence bladder inhibition generated by sensory pudendal nerve stimulation in control rats, whereas HGNT and propranolol decreased the efficacy of electrical stimulation in CYP rats. Conclusions: Sympathetic reflex activity mediates sensory pudendal nerve stimulation in CYP treated but not control rats. These studies demonstrate an alternative approach to neuromodulation in cystitis and establish mechanistic changes during stimulation that may enable the development of novel therapeutics. [ABSTRACT FROM AUTHOR]
- Published
- 2019
- Full Text
- View/download PDF
27. Influence of Elbow Flexion and Stimulation Site on Neuromuscular Electrical Stimulation of the Biceps Brachii.
- Author
-
Gonzalez, Eric J., Downey, Ryan J., Rouse, Courtney A., and Dixon, Warren E.
- Subjects
ELECTRIC stimulation ,ELECTRODES ,MOTOR neurons ,ELBOW physiology ,TORQUE measurements - Abstract
Functional electrical stimulation (FES) can help individuals with physical disabilities by assisting limb movement; however, the change in muscle geometry associated with limb movement may affect the response to stimulation. The aim of this paper was to quantify the effects of elbow flexion and stimulation site on muscle torque production. Contraction torque about the elbow was measured in 12 healthy individuals using a custom elbow flexion testbed and a transcutaneous electrode array. Stimulation was delivered to six distinct sites along the biceps brachii over 11 elbow flexion angles. Flexion angle was found to significantly influence the optimal (i.e., torque-maximizing) stimulation site ( \chi ^2 (10, \mathrm N=24) = 135.75, \mathrm p = 3.12\times 10^-24 ), with post hoc analysis indicating a proximal shift in optimal stimulation site with increased flexion. Similarly, the biceps stimulation site was found to significantly influence the flexion angle at which peak torque occurred ( \chi ^2(5,\mathrm N=24) = 101.82,\mathrm p =2.18\times 10^-20 ), with post hoc analysis indicating an increase in peak-torque flexion angle as stimulation site is moved proximally up the biceps. Since maximizing muscle force per unit stimulation is a common goal in rehabilitative FES, future efforts could examine methods which compensate for the shift in optimal stimulation site during FES-induced limb movement. [ABSTRACT FROM PUBLISHER]
- Published
- 2018
- Full Text
- View/download PDF
28. Inherent steroid 17α,20-lyase activity in defunct cytochrome P450 17A enzymes.
- Author
-
Gonzalez, Eric, Johnson, Kevin M., Pallan, Pradeep S., Phan, Thanh T. N., Wei Zhang, Li Lei, Wawrzak, Zdzislaw, Yoshimoto, Francis K., Egli, Martin, and Guengerich, F. Peter
- Subjects
- *
STEROIDS , *LYASES , *CYTOCHROME P-450 , *PROGESTERONE , *PREGNENOLONE , *HYDROXYLATION - Abstract
Cytochrome P450 (P450) 17A1 catalyzes the oxidations of progesterone and pregnenolone and is the major source of androgens. The enzyme catalyzes both 17α-hydroxylation and a subsequent 17α,20-lyase reaction, and several mechanisms have been proposed for the latter step. Zebrafish P450 17A2 catalyzes only the 17α-hydroxylations. We previously reported high similarity of the crystal structures of zebrafish P450 17A1 and 17A2 and human P450 17A1. Five residues near the heme, which differed, were changed. We also crystallized this five-residue zebrafish P450 17A1 mutant, and the active site still resembled the structure in the other proteins, with some important differences. These P450 17A1 and 17A2 mutants had catalytic profiles more similar to each other than did the wildtype proteins. Docking with these structures can explain several minor products, which require multiple enzyme conformations. The 17α-hydroperoxy (OOH) derivatives of the steroids were used as oxygen surrogates. Human P450 17A1 and zebrafish P450s 17A1 and P450 17A2 readily converted these to the lyase products in the absence of other proteins or cofactors (with catalytically competent kinetics) plus hydroxylated 17α-hydroxysteroids. The 17α-OOH results indicate that a "Compound I" (FeO3+) intermediate is capable of formation and can be used to rationalize the products. We conclude that zebrafish P450 17A2 is capable of lyase activity with the 17α-OOH steroids because it can achieve an appropriate conformation for lyase catalysis in this system that is precluded in the conventional reaction. [ABSTRACT FROM AUTHOR]
- Published
- 2018
- Full Text
- View/download PDF
29. Isotope-Labeling Studies Support the Electrophilic Compound I Iron Active Species, FeO3+, for the Carbon-Carbon Bond Cleavage Reaction of the Cholesterol Side-Chain Cleavage Enzyme, Cytochrome P450 11A1.
- Author
-
Yoshimoto, Francis K., I-Ji Jung, Goyal, Sandeep, Gonzalez, Eric, and Guengerich, F. Peter
- Published
- 2017
- Full Text
- View/download PDF
30. The effects of neuromodulation in a novel obese-prone rat model of detrusor underactivity.
- Author
-
Gonzalez, Eric J. and Grill, Warren M.
- Abstract
Obesity is a global epidemic associated with an increased risk for lower urinary tract dysfunction. Inefficient voiding and urinary retention may arise in late-stage obesity when the expulsive force of the detrusor smooth muscle cannot overcome outlet resistance. Detrusor underactivity (DUA) and impaired contractility may contribute to the pathogenesis of nonobstructive urinary retention. We used cystometry and electrical stimulation of peripheral nerves (pudendal and pelvic nerves) to characterize and improve bladder function in urethane-anesthetized obeseprone (OP) and obese-resistant (OR) rats following diet-induced obesity (DIO). OP rats exhibited urinary retention and impaired detrusor contractility following DIO, reflected as increased volume threshold, decreased peak micturition pressure, and decreased voiding efficiency (VE) compared with OR rats. Electrical stimulation of the sensory branch of the pudendal nerve did not increase VE, whereas patterned bursting stimulation of the motor branch of the pudendal nerve increased VE twofold in OP rats. OP rats required increased amplitude of electrical stimulation of the pelvic nerve to elicit bladder contractions, and maximum evoked bladder contraction amplitudes were decreased relative to OR rats. Collectively, these studies characterize a novel animal model of DUA that can be used to determine pathophysiology and suggest that neuromodulation is a potential management option for DUA. [ABSTRACT FROM AUTHOR]
- Published
- 2017
- Full Text
- View/download PDF
31. The Time-Varying Nature of Electromechanical Delay and Muscle Control Effectiveness in Response to Stimulation-Induced Fatigue.
- Author
-
Downey, Ryan J., Merad, Manelle, Gonzalez, Eric J., and Dixon, Warren E.
- Subjects
ELECTRIC stimulation ,FATIGUE (Physiology) ,REHABILITATION technology ,QUADRICEPS muscle ,TORQUE - Abstract
Neuromuscular electrical stimulation (NMES) and Functional Electrical Stimulation (FES) are commonly prescribed rehabilitative therapies. Closed-loop NMES holds the promise to yield more accurate limb control, which could enable new rehabilitative procedures. However, NMES/FES can rapidly fatigue muscle, which limits potential treatments and presents several control challenges. Specifically, the stimulation intensity-force relation changes as the muscle fatigues. Additionally, the delayed response between the application of stimulation and muscle force production, termed electromechanical delay (EMD), may increase with fatigue. This paper quantifies these effects. Specifically, open-loop fatiguing protocols were applied to the quadriceps femoris muscle group of able-bodied individuals under isometric conditions, and the resulting torque was recorded. Short pulse trains were used to measure EMD with a thresholding method while long duration pulse trains were used to induce fatigue, measure EMD with a cross-correlation method, and construct recruitment curves. EMD was found to increase significantly with fatigue, and the control effectiveness (i.e., the linear slope of the recruitment curve) decreased with fatigue. Outcomes of these experiments indicate an opportunity for improved closed-loop NMES/FES control development by considering EMD to be time-varying and by considering the muscle recruitment curve to be a nonlinear, time-varying function of the stimulation input. [ABSTRACT FROM AUTHOR]
- Published
- 2017
- Full Text
- View/download PDF
32. Kinetic processivity of the two-step oxidations of progesterone and pregnenolone to androgens by human cytochrome P450 17A1.
- Author
-
Gonzalez, Eric and Guengerich, F. Peter
- Subjects
- *
PROGESTERONE , *PREGNENOLONE , *CYTOCHROME P-450 , *ANDROGENS , *GLUCOCORTICOIDS , *PHYSIOLOGY - Abstract
Cytochrome P450 (P450, CYP) 17A1 plays a critical role in steroid metabolism, catalyzing both the 17α-hydroxylation of pregnenolone and progesterone and the subsequent 17α,20-lyase reactions to form dehydroepiandrosterone (DHEA) and androstenedione (Andro), respectively, critical for generating glucocorticoids and androgens. Human P450 17A1 reaction rates examined are enhanced by the accessory protein cytochrome b5 (b5), but the exact role of b5 in P450 17A1-catalyzed reactions is unclear as are several details of these reactions. Here, we examined in detail the processivity of the 17α-hydroxylation and lyase steps. b5 did not enhance reaction rates by decreasing the koff rates of any of the steroids. Steroid binding to P450 17A1 was more complex than a simple two-state system. Pre-steady-state experiments indicated lag phases for Andro production from progesterone and for DHEA from pregnenolone, indicating a distributive character of the enzyme. However, we observed processivity in pregnenolone/DHEA pulse-chase experiments. (S)-Orteronel was three times more inhibitory toward the conversion of 17α-hydroxypregnenolone to DHEA than toward the 17α-hydroxylation of pregnenolone. IC50 values for (S)-orteronel were identical for blocking DHEA formation from pregnenolone and for 17α-hydroxylation, suggestive of processivity. Global kinetic modeling helped assign sets of rate constants for individual or groups of reactions, indicating that human P450 17A1 is an inherently distributive enzyme but that some processivity is present, i.e. some of the 17α-OH pregnenolone formed from pregnenolone did not dissociate from P45017A1 before conversion to DHEA. Our results also suggest multiple conformations of P450 17A1, as previously proposed on the basis of NMR spectroscopy and X-ray crystallography. [ABSTRACT FROM AUTHOR]
- Published
- 2017
- Full Text
- View/download PDF
33. Isotope-Labeling Studies Support the Electrophilic Compound I Iron Active Species, FeO3+, for the Carbon-Carbon Bond Cleavage Reaction of the Cholesterol Side-Chain Cleavage Enzyme, Cytochrome P450 11A1.
- Author
-
Yoshimoto, Francis K., I-Ji Jung, Goyal, Sandeep, Gonzalez, Eric, and Guengerich, F. Peter
- Published
- 2016
- Full Text
- View/download PDF
34. Mechanism of 17α,20-Lyase and New Hydroxylation Reactions of Human Cytochrome P450 17A1.
- Author
-
Yoshimoto, Francis K., Gonzalez, Eric, Auchus, Richard J., and Guengerich, F. Peter
- Subjects
- *
HYDROXYLATION , *CYTOCHROME P-450 , *STEROLS , *HYDROXYPROGESTERONE , *ACETIC acid - Abstract
Cytochrome P450 (P450) reactions can involve C-C bond cleavage, and several of these are critical in steroid and sterol biosynthesis. The mechanisms of P450s 11A1, 17A1, 19A1, and 51A1 have been controversial, in the context of the role of ferric peroxide (FeO2-) versus perferryl (FeO3+, compound I) chemistry. We reinvestigated the 17α-hydroxyprogesterone and 17α- hydroxypregnenolone 17α,20-lyase reactions of human P450 17A1 and found incorporation of one 18Oatom (from 18O2) into acetic acid, consonant with proposals for a ferric peroxide mechanism (Akhtar, M., Lee-Robichaud, P., Akhtar, M. E., and Wright, J. N. (1997) J. Steroid Biochem. Mol. Biol. 61, 127-132; Akhtar, M., Wright, J. N., and Lee-Robichaud, P. (2011) J. Steroid Biochem. Mol. Biol. 125, 2-12). However, the reactions were supported by iodosylbenzene (a precursor of the FeO3+ species) but not by H2O2. We propose three mechanisms that can involve the FeO3+entity and that explain the 18Olabel in the acetic acid, two involving the intermediacy of an acetyl radical and one a steroid 17,20-dioxetane. P450 17A1 was found to perform 16-hydroxylation reactions on its 17α-hydroxylated products to yield 16,17α-dihydroxypregnenolone and progesterone, suggesting the presence of an active perferryloxo active species of P450 17A1 when its lyase substrate is bound. The 6β-hydroxylation of 16α,17α-dihydroxyprogesterone and the oxidation of both 16α,17α-dihydroxyprogesterone and 16α,17α-dihydroxypregnenolone to 16-hydroxy lyase products were also observed. We provide evidence for the contribution of a compound I mechanism, although contribution of a ferric peroxide pathway in the 17α,20-lyase reaction cannot be excluded. [ABSTRACT FROM AUTHOR]
- Published
- 2016
- Full Text
- View/download PDF
35. Purinergic signalling underlies transforming growth factor-β-mediated bladder afferent nerve hyperexcitability.
- Author
-
Gonzalez, Eric J., Heppner, Thomas J., Nelson, Mark T., and Vizzard, Margaret A.
- Subjects
- *
BLADDER injuries , *GROWTH factors , *AFFERENT pathways , *CYSTITIS , *PANNEXINS - Abstract
Key points The sensory components of the urinary bladder are responsible for the transduction of bladder filling and are often impaired with neurological injury or disease., Elevated extracellular ATP contributes, in part, to bladder afferent nerve hyperexcitability during urinary bladder inflammation or irritation., Transforming growth factor-β1 (TGF-β1) may stimulate ATP release from the urothelium through vesicular exocytosis mechanisms with minimal contribution from pannexin-1 channels to increase bladder afferent nerve discharge., Bladder afferent nerve hyperexcitability and urothelial ATP release with CYP-induced cystitis is decreased with TGF-β inhibition., These results establish a causal link between an inflammatory mediator, TGF-β, and intrinsic signalling mechanisms of the urothelium that may contribute to the altered sensory processing of bladder filling., Abstract The afferent limb of the micturition reflex is often compromised following bladder injury, disease and inflammatory conditions. We have previously demonstrated that transforming growth factor-β (TGF-β) signalling contributes to increased voiding frequency and decreased bladder capacity with cystitis. Despite the functional presence of TGF-β in bladder inflammation, the precise mechanisms of TGF-β mediating bladder dysfunction are not yet known. Thus, the present studies investigated the sensory components of the urinary bladder that may underlie the pathophysiology of aberrant TGF-β activation. We utilized bladder-pelvic nerve preparations to characterize bladder afferent nerve discharge and the mechanisms of urothelial ATP release with distention. Our findings indicate that bladder afferent nerve discharge is sensitive to elevated extracellular ATP during pathological conditions of urinary bladder inflammation or irritation. We determined that TGF-β1 may increase bladder afferent nerve excitability by stimulating ATP release from the urothelium via vesicular exocytosis mechanisms with minimal contribution from pannexin-1 channels. Furthermore, blocking aberrant TGF-β signalling in cyclophosphamide-induced cystitis with TβR-1 inhibition decreased afferent nerve hyperexcitability with a concomitant decrease in urothelial ATP release. Taken together, these results establish a role for purinergic signalling mechanisms in TGF-β-mediated bladder afferent nerve activation that may ultimately facilitate increased voiding frequency. The synergy between intrinsic urinary bladder signalling mechanisms and an inflammatory mediator provides novel insight into bladder dysfunction and supports new avenues for therapeutic intervention. [ABSTRACT FROM AUTHOR]
- Published
- 2016
- Full Text
- View/download PDF
36. Acoustic firearm discharge detection and classification in an enclosed environment.
- Author
-
Luzi, Lorenzo, Gonzalez, Eric, Bruillard, Paul, Prowant, Matthew, Skorpik, James, Hughes, Michael, Child, Scott, Kist, Duane, and McCarthy, John E.
- Subjects
- *
GUNFIRE detection systems , *ACOUSTIC transducers , *FIREARMS , *LOGARITHMS , *SIGNAL processing , *ALGORITHMS , *MICROPHONES , *MICROCONTROLLERS - Abstract
Two different signal processing algorithms are described for detection and classification of acoustic signals generated by firearm discharges in small enclosed spaces. The first is based on the logarithm of the signal energy. The second is a joint entropy. The current study indicates that a system using both signal energy and joint entropy would be able to both detect weapon discharges and classify weapon type, in small spaces, with high statistical certainty. [ABSTRACT FROM AUTHOR]
- Published
- 2016
- Full Text
- View/download PDF
37. Fragment-Based Protein-Protein Interaction Antagonists of a Viral Dimeric Protease.
- Author
-
Gable, Jonathan E., Lee, Gregory M., Acker, Timothy M., Hulce, Kaitlin R., Gonzalez, Eric R., Schweigler, Patrick, Melkko, Samu, Farady, Christopher J., and Craik, Charles S.
- Published
- 2016
- Full Text
- View/download PDF
38. The Effects of Tempol on Cyclophosphamide-Induced Oxidative Stress in Rat Micturition Reflexes.
- Author
-
Gonzalez, Eric J., Peterson, Abbey, Malley, Susan, Daniel, Mitchel, Lambert, Daniel, Kosofsky, Michael, and Vizzard, Margaret A.
- Subjects
CYCLOPHOSPHAMIDE ,TEMPOL ,OXIDATIVE stress ,URINATION ,LABORATORY mice - Abstract
We hypothesized that cyclophosphamide- (CYP-) induced cystitis results in oxidative stress and contributes to urinary bladder dysfunction. We determined (1) the expression of oxidative stress markers 3-nitrotyrosine (3-NT), reactive oxygen species (ROS)/reactive nitrogen species (RNS), inflammatory modulators, neuropeptides calcitonin gene-related peptide (CGRP), substance P (Sub P), and adenosine triphosphate (ATP) that contribute to the inflammatory process in the urinary tract and (2) the functional role of oxidative stress in urinary bladder dysfunction with an antioxidant, Tempol, (1 mM in drinking water) combined with conscious cystometry. In CYP-treated (4 hr or 48 hr; 150 mg/kg, i.p.) rats, ROS/RNS and 3-NT significantly (P≤0.01) increased in urinary bladder. CYP treatment increased ATP, Sub P, and CGRP expression in the urinary bladder and cystometric fluid. In CYP-treated rats, Tempol significantly (P≤0.01) increased bladder capacity and reduced voiding frequency compared to CYP-treated rats without Tempol. Tempol significantly (P≤0.01) reduced ATP expression, 3-NT, and ROS/RNS expression in the urinary tract of CYP-treated rats. These studies demonstrate that reducing oxidative stress in CYP-induced cystitis improves urinary bladder function and reduces markers of oxidative stress and inflammation. [ABSTRACT FROM AUTHOR]
- Published
- 2015
- Full Text
- View/download PDF
39. Point spread function for PET detectors based on the probability density function of the line segment.
- Author
-
Gonzalez, Eric, Cui, Jing-yu, Pratx, Guillem, Bieniosek, Matthew, Olcott, Peter D., and Levin, Craig S.
- Abstract
We propose a new approach to calculate the Point Spread Function (PSF) for PET detectors based on the probability density function (PDF) of the line segment connecting two detector elements. Positron Emission Tomography (PET) events comprise the detection and positioning of pairs of oppositely directed 511 keV photons. The most significant blurring effect in PET is the considerable size of the detector elements, which causes uncertainty in the detected positions of photons. Typically this physical blurring is modeled in the forward direction, following photons from the source to the detectors. This work presents an analytical framework for calculating this physical blurring, from the inverse approach, that is from the detector to the source. The kernel is derived from the parameterization of the line segment whose endpoints are random variables described by the intrinsic detector response function distribution. This kernel is calculated in a first order approximation, and when compared against a measured PSF profile yields less than 8% root mean square (RMS) differences. Also, from this kernel a PSF-FWHM function of the distance to the center of the scanner is derived. The ratio between the PSF-FWHM and the intrinsic detector resolution (FWHM0) agrees with the Monte Carlo simulations. For detectors whose intrinsic response functions are described by Gaussian profiles we calculated ratios 1/√2 and √5/8 at the center (R=0) and halfway from the center at ( R=system-radius/2) respectively in agreement with published values of 1/√2 and 0.85; similarly for uniform (rectangular) profiles we get 1/2 and 3/4 which are equal to published values. [ABSTRACT FROM PUBLISHER]
- Published
- 2011
- Full Text
- View/download PDF
40. Methods for increasing the sensitivity of simultaneous multi-isotope positron emission tomography.
- Author
-
Gonzalez, Eric, Olcott, Peter D., Bieniosek, Matthew, and Levin, Craig S.
- Abstract
Multi-isotope PET (MIP) can distinguish thebiodistributions of two simultaneously injected PET tracers, where one tracer has an isotope that is a pure positron emitter that generates two-photon coincidences, and the other emits a positron and a gamma ray in cascade yielding a triple coincidence.1 However triple coincidence detection suffers from very low sensitivity. This work presents a method to significantly enhance the sensitivity of triple coincidences for multi-isotope PET by adding an extra detector dedicated for the detection of the third prompt gamma in coincidence with the annihilation photons. We performed Monte Carlo simulations with I124, Sc-44, and F-18 isotopes, and measurements with Na-22 and Ge-68. F-18 and Ge-68 are pure positron emitters; on the other hand I124, Sc-44, and Na-22 emit 603 keV, 1156 keV and 1275 keV prompt gamma rays respectively. For the simulations, a phantom was acquired in a simulated Siemens Inveon system with 8 cm diameter, 5 cm thick detector slab of BGO placed at one end of the system to increase detection efficiency of the third gamma ray. The simulations indicate about a twofold increase in sensitivity with the extra detector added. For the measurements, we arranged two LYSO crystals coupled to Hamamatsu MMPC silicon photomultipliers (SiPM)s for the detection of 511 keV photons in coincidences and one large 8cm diameter, 2cm thick detector slab of LYSO coupled to a PMT dedicated for the detection of the 1275 keV gamma ray. The measured ratio of the triple-coincidence counts divided by the double-coincidence detection counts is 0.037±0.003, which compares well with the analytically calculated ratio of 0.042 estimated from intrinsic and geometry efficiency considerations. Furthermore, the 511 keV scintillation detectors were mounted on a linear stage that translated the detectors while acquiring double and triple coincidences counts simultaneously in order to generate one-dimensional profiles of the Na-22 and Ge-68 point sources. The triple-coincidence allows the distinction of Na-22 point source profile from the standard 511 keV double-coincidence profile of the Ge-68 source. [ABSTRACT FROM PUBLISHER]
- Published
- 2011
- Full Text
- View/download PDF
41. Bladder sensory physiology: neuroactive compounds and receptors, sensory transducers, and target-derived growth factors as targets to improve function.
- Author
-
Gonzalez, Eric J., Merrill, Liana, and Vizzard, Margaret A.
- Subjects
- *
BLADDER physiology , *SENSORY neurons , *NEUROPEPTIDES , *TRP channels , *URINATION , *ADENOSINE triphosphate - Abstract
Urinary bladder dysfunction presents a major problem in the clinical management of patients suffering from pathological conditions and neurological injuries or disorders. Currently, the etiology underlying altered visceral sensations from the urinary bladder that accompany the chronic pain syndrome, bladder pain syndrome (BPS)/ interstitial cystitis (IC), is not known. Bladder irritation and inflammation are histopathological features that may underlie BPS/IC that can change the properties of lower urinary tract sensory pathways (e.g., peripheral and central sensitization, neurochemical plasticity) and contribute to exaggerated responses of peripheral bladder sensory pathways. Among the potential mediators of peripheral nociceptor sensitization and urinary bladder dysfunction are neuroactive compounds (e.g., purinergic and neuropeptide and receptor pathways), sensory transducers (e.g., transient receptor potential channels) and target-derived growth factors (e.g., nerve growth factor). We review studies related to the organization of the afferent limb of the micturition reflex and discuss neuroplasticity in an animal model of urinary bladder inflammation to increase the understanding of functional bladder disorders and to identify potential novel targets for development of therapeutic interventions. Given the heterogeneity of BPS/IC and the lack of consistent treatment benefits, it is unlikely that a single treatment directed at a single target in micturition reflex pathways will have a mass benefit. Thus, the identification of multiple targets is a prudent approach, and use of cocktail treatments directed at multiple targets should be considered. [ABSTRACT FROM AUTHOR]
- Published
- 2014
- Full Text
- View/download PDF
42. The Role(s) of Cytokines/Chemokines in Urinary Bladder Inflammation and Dysfunction.
- Author
-
Gonzalez, Eric J., Arms, Lauren, and Vizzard, Margaret A.
- Abstract
Bladder pain syndrome (BPS)/interstitial cystitis (IC) is a chronic pain syndrome characterized by pain, pressure, or discomfort perceived to be bladder related and with at least one urinary symptom. It was recently concluded that 3.3-7.9 million women (>18 years old) in the United States exhibit BPS/IC symptoms. The impact of BPS/IC on quality of life is enormous and the economic burden is significant. Although the etiology and pathogenesis of BPS/IC are unknown, numerous theories including infection, inflammation, autoimmune disorder, toxic urinary agents, urothelial dysfunction, and neurogenic causes have been proposed. Altered visceral sensations from the urinary bladder (i.e., pain at low or moderate bladder filling) that accompany BPS/IC may be mediated by many factors including changes in the properties of peripheral bladder afferent pathways such that bladder afferent neurons respond in an exaggerated manner to normally innocuous stimuli (allodynia). The goals for this review are to describe chemokine/receptor (CXCL12/CXCR4; CCL2/CCR2) signaling and cytokine/receptor (transforming growth factor (TGF-β)/TGF-β type 1 receptor) signaling that may be valuable LUT targets for pharmacologic therapy to improve urinary bladder function and reduce somatic sensitivity associated with urinary bladder inflammation. [ABSTRACT FROM AUTHOR]
- Published
- 2014
- Full Text
- View/download PDF
43. Expression and function of transforming growth factor-β isoforms and cognate receptors in the rat urinary bladder following cyclophosphamide-induced cystitis.
- Author
-
Gonzalez, Eric J., Girard, Beatrice M., and Vizzard, Margaret A.
- Subjects
- *
GENE expression , *TRANSFORMING growth factors , *LABORATORY rats , *BLADDER , *CYCLOPHOSPHAMIDE , *CYSTITIS , *CYTOKINES , *INFLAMMATION , *THERAPEUTICS - Abstract
Numerous proinflammatory cytokines have been implicated in the reorganization of lower urinary tract function following cyclophosphamide (CYP)- induced cystitis. The present study investigated the functional profile of three pleiotropic transforming growth factor-β (TGF-β) isoforms and receptor (TβR) variants in the normal and inflamed (CYP-induced cystitis) rat urinary bladder. Our findings indicate that TGF-β (1, 2, and 3) and TβR (1, 2, and 3) transcript and protein expression were regulated to varying degrees in the urothelium or detrusor smooth muscle following intermediate (48 h; 150 mg/kg ip) or chronic (75 mg/kg ip; once every 3 days for 10 days), but not acute (4 h; 150 mg/kg ip), CYP-induced cystitis. Conscious, open-outlet cystometry was performed to determine whether aberrant TGF-β signaling contributes to urinary bladder dysfunction following intermediate (48 h) CYP-induced cystitis. TβR-1 inhibition with SB505124 (5 μM) significantly (p ≤ 0.001) decreased voiding frequency and increased bladder capacity (2.5-fold), void volume (2.6-fold), and intercontraction intervals (2.5-fold) in CYP-treated (48 h) rats. Taken together, these results provide evidence for 1) the involvement of TGF-β in lower urinary tract neuroplasticity following urinary bladder inflammation, 2) a functional role of TGF-β signaling in the afferent limb of the micturition reflex, and 3) urinary bladder TβR-1 as a viable target to reduce voiding frequency with cystitis. [ABSTRACT FROM AUTHOR]
- Published
- 2013
- Full Text
- View/download PDF
44. Fresh MESA improved embryo fertilization, cleavage, blastula formation and implantation rates after failed TESA in couples with obstructive azoospermia.
- Author
-
Keltz, Martin, Rovner, Elisheva, Gonzalez, Eric, and Weiner, David
- Subjects
MALE infertility ,SPERMATOZOA ,EMBRYOS ,BLASTULA ,PREGNANCY ,CHILDBIRTH - Abstract
Purpose: To determine whether our use of fresh MESA cycles improved outcomes in patients with obstructive azoospermia who had failed IVF with TESA. Methods: A prospective observational trial of couples undergoing IVF for obstructive azoospermia was performed at an academic IVF center. Results: When TESA resulted in poor embryo cleavage, implantation and ongoing pregnancy rates, subsequent fresh MESA cycles in these same couples, demonstrated dramatic improvement in cleavage, blastulation, implantation and live birth rates. Conclusions: In patients undergoing IVF-TESA-ICSI with obstructive azoospermia resulting in poor cleavage rates, blastulation rates and cycle failure, a repeat cycle with MESA may result in marked improvement in outcome. [ABSTRACT FROM AUTHOR]
- Published
- 2011
- Full Text
- View/download PDF
45. La visibilitat internacional de la investigació científica : el cas de la Universidad Nacional Autónoma de México
- Author
-
González, Eric, Gómez Hernández, José A., and Licea de Arenas, Judith
- Subjects
Universidad Nacional Autónoma de México ,Scientific research ,Visibility ,Mexico ,Bibliometric analysis ,Universities ,Bibliography. Library science. Information resources ,Communication. Mass media ,P87-96 - Abstract
La Universidad Nacional Autónoma de México té les funcions substantives següents: la docència, la recerca i la difusió de la cultura. L’acompliment li ha valgut reconeixements nacionals i internacionals que l'han col·locat com la més destacada a escala nacional i en llocs importants a escala internacional. Tanmateix, fins avui la Universidad no disposa d'indicadors que donin a conèixer el grau de desenvolupament al qual ha arribat la recerca que s'hi duu a terme. L'objectiu d'aquest treball és determinar l'acompliment dels investigadors universitaris en el període 1995–2003 a través d'una anàlisi bibliomètrica. La construcció de les dades empíriques es va basar en el Web of Knowledge i el Journal Citation Reports (JCR), i va servir per determinar el grau de visibilitat del canal de comunicació utilitzat per difondre els productes de la tasca científica. Es van identificar 9.903 articles que van aconseguir acumular 65.291 citacions. Els articles es van publicar, la majoria, en disciplines corresponents a les ciències dures. Les disciplines en què hi va haver més activitat científica van ser l'astronomia i l'astrofísica, la bioquímica i la biologia molecular i física. Es conclou que els investigadors de la UNAM han superat en part les barreres que impedeixen la incorporació de la ciència mexicana a l'àmbit de la ciència visible, que és el que compta.The Universidad Nacional Autónoma de México (UNAM) has the following functions: teaching, research, and the dissemination of culture. It has gained national and international recognition for its achievements, and is currently ranked first in the country and among the best in the international classifications. However, no research performance indicators exist for this university. The aim of the present paper is to assess the performance of university researchers during the period 1995-2003 using a bibliometrical analysis. The empirical data were based on the Web of Knowledge and the Journal Citation Reports (JCR). They were used to assess the degree of visibility of the communication channel used to disseminate the products of scientific research. 9,903 articles were identified which obtained 65,291 citations. Most articles were published in disciplines in the hard sciences: astronomy and astrophysics, biochemistry and molecular biology and physics. We conclude that UNAM researchers have partially overcome the obstacles facing the consolidation of Mexican science as it seeks a wider public.
- Published
- 2008
- Full Text
- View/download PDF
46. Molecular mechanisms of isocitrate dehydrogenase 1 (IDH1) mutations identified in tumors: The role of size and hydrophobicity at residue 132 on catalytic efficiency.
- Author
-
Matteo, Diego Avellaneda, Grunseth, Adam J., Gonzalez, Eric R., Anselmo, Stacy L., Kennedy, Madison A., Moman, Precious, Scott, David A., An Hoang, and Sohl, Christal D.
- Subjects
- *
ISOCITRATE dehydrogenase , *ISOCITRATE lyase , *PEROXISOMES , *CYTOSOL , *GLIOBLASTOMA multiforme - Abstract
Isocitrate dehydrogenase 1 (IDH1) catalyzes the reversible NADP+-dependent conversion of isocitrate (ICT) to α-ketoglutarate (αKG)s in the cytosol and peroxisomes. Mutations in IDH1 have been implicated in>80% of lower grade gliomas and secondary glioblastomas and primarily affect residue 132, which helps coordinate substrate binding. However, other mutations found in the active site have also been identified in tumors. IDH1 mutations typically result in a loss of catalytic activity, but many also can catalyze a new reaction, the NADPH-dependent reduction of αKG to D-2-hydroxyglutarate (D2HG). D2HG is a proposed oncometabolite that can competitively inhibit αKG-dependent enzymes. Some kinetic parameters have been reported for several IDH1 mutations, and there is evidence that mutant IDH1 enzymes vary widely in their ability to produce D2HG. We report that most IDH1 mutations identified in tumors are severely deficient in catalyzing the normal oxidation reaction, but that D2HG production efficiency varies among mutant enzymes up to ~640-fold. Common IDH1 mutations have moderate catalytic efficiencies for D2HG production, whereas rarer mutations exhibit either very low or very high efficiencies. We then designed a series of experimental IDH1 mutants to understand the features that support D2HG production. Weshow that this new catalytic activity observed in tumors is supported by mutations at residue 132 that have a smaller van der Waals volume and are more hydrophobic. We report that one mutation can support both the normal and neomorphic reactions. These studies illuminate catalytic features of mutations found in the majority of patients with lower grade gliomas. [ABSTRACT FROM AUTHOR]
- Published
- 2017
- Full Text
- View/download PDF
47. P4-76: Efficacy and safety of cooled-tip versus 8-mm-tip catheter for electro-anatomical encircling of pulmonary veins for atrial fibrillation. Is there a real benefit?
- Author
-
Matiello, Maria, Tamborero, David, Gonzalez, Eric, Molina, Irma, Berruezo, Antonio, Brugada, Josep, and Mont, Lluı́s
- Published
- 2006
- Full Text
- View/download PDF
48. Structural and Kinetic Basis of Steroid 17α,20-Lyase Activity in Teleost Fish Cytochrome P450 17A1 and Its Absence in Cytochrome P450 17A2.
- Author
-
Pallan, Pradeep S., Nagy, Leslie D., Li Lei, Gonzalez, Eric, Kramlinger, Valerie M., Azumaya, Caleigh M., Wawrzak, Zdzislaw, Waterman, Michael R., Guengerich, F. Peter, and Egli, Martin
- Subjects
- *
OSTEICHTHYES , *CYTOCHROMES , *STEROIDS , *FISH research , *LYASES - Abstract
Cytochrome P450 (P450) 17A enzymes play a critical role in the oxidation of the steroids progesterone (Prog) and pregnenolone (Preg) to glucocorticoids and androgens. In mammals, a single enzyme, P450 17A1, catalyzes both 17α-hydroxylation and a subsequent 17α,20-lyase reaction with both Prog and Preg. Teleost fish contain two 17A P450s; zebrafish P450 17A1 catalyzes both 17α-hydroxylation and lyase reactions with Prog and Preg, and P450 17A2 is more efficient in pregnenolone 17α- hydroxylation but does not catalyze the lyase reaction, even in the presence of cytochrome b5. P450 17A2 binds all substrates and products, although more loosely than P450 17A1. Pulsechase and kinetic spectral experiments and modeling established that the two-step P450 17A1 Prog oxidation is more distributive than the Preg reaction, i.e. 17α-OHproduct dissociates more prior to the lyase step. The drug orteronel selectively blocked the lyase reaction of P450 17A1 but only in the case of Prog. X-ray crystal structures of zebrafish P450 17A1 and 17A2 were obtained with the ligand abiraterone and with Prog for P450 17A2. Comparison of the two fish P450 17A-abiraterone structures with human P450 17A1 (DeVore, N. M., and Scott, E. E. (2013) Nature 482, 116-119) showed only a few differences near the active site, despite only ~50% identity among the three proteins. The P450 17A2 structure differed in four residues near the heme periphery. These residues may allow the proposed alternative ferric peroxide mechanism for the lyase reaction, or residues removed from the active site may allow conformations that lead to the lyase activity. [ABSTRACT FROM AUTHOR]
- Published
- 2015
- Full Text
- View/download PDF
Catalog
Discovery Service for Jio Institute Digital Library
For full access to our library's resources, please sign in.