Ayala FJ
Department of Ecology and Evolutionary Biology, University of California, Irvine, CA 92697, USA. fjayala@uci.edu
|
Darwin and the scientific method.
Proc Natl Acad Sci U S A. 2009 Jun 16;106 Suppl 1:10033-9
There is a contradiction between Darwin's methodology and how he described it for public consumption. Darwin claimed that he proceeded "on true Baconian [inductive] principles and without any theory collected facts on a wholesale scale." He also wrote, "How odd it is that anyone should not see that all observation must be for or against some view if it is to be of any service!" The scientific method includes 2 episodes. The first consists of formulating hypotheses; the second consists of experimentally testing them. What differentiates science from other knowledge is the second episode: subjecting hypotheses to empirical testing by observing whether or not predictions derived from a hypothesis are the case in relevant observations and experiments. A hypothesis is scientific only if it is consistent with some but not other possible states of affairs not yet observed, so that it is subject to the possibility of falsification by reference to experience. Darwin occupies an exalted place in the history of Western thought, deservedly receiving credit for the theory of evolution. In The Origin of Species, he laid out the evidence demonstrating the evolution of organisms. More important yet is that he discovered natural selection, the process that accounts for the adaptations of organisms and their complexity and diversification. Natural selection and other causal processes of evolution are investigated by formulating and testing hypotheses. Darwin advanced hypotheses in multiple fields, including geology, plant morphology and physiology, psychology, and evolution, and subjected them to severe empirical tests.
PMID: 19528662
|
Avise JC,Ayala FJ
Department of Ecology and Evolutionary Biology, University of California, Irvine, CA 92697, USA. javise@uci.edu
|
In the light of evolution III: two centuries of Darwin.
Proc Natl Acad Sci U S A. 2009 Jun 16;106 Suppl 1:9933-8
PMID: 19528649
|
McCaughey RG,Sun H,Rothholtz VS,Juhasz T,Wong BJ
University of California, Irvine, Beckman Laser Institute and Medical Clinic, 1002 Health Sciences Road, Irvine, Calfornia 92612, USA. rmccaugh@uci.edu
|
Femtosecond laser ablation of the stapes.
J Biomed Opt. 14(2):024040
A femtosecond laser, normally used for LASIK eye surgery, is used to perforate cadaveric human stapes. The thermal side effects of bone ablation are measured with a thermocouple in an inner ear model and are found to be within acceptable limits for inner ear surgery. Stress and acoustic events, recorded with piezoelectric film and a microphone, respectively, are found to be negligible. Optical microscopy, scanning electron microscopy, and optical coherence tomography are used to confirm the precision of the ablation craters and lack of damage to the surrounding tissue. Ablation is compared to that from an Er:YAG laser, the current laser of choice for stapedotomy, and is found to be superior. Ultra-short-pulsed lasers offer a precise and efficient ablation of the stapes, with minimal thermal and negligible mechanical and acoustic damage. They are, therefore, ideal for stapedotomy operations.
PMID: 19405768
|
Rex CS,Chen LY,Sharma A,Liu J,Babayan AH,Gall CM,Lynch G
Department of Psychiatry and Human Behavior, University of California, Irvine, CA 92697, USA. crex@uci.edu
|
Different Rho GTPase-dependent signaling pathways initiate sequential steps in the consolidation of long-term potentiation.
J Cell Biol. 2009 Jul 13;186(1):85-97
The releasable factor adenosine blocks the formation of long-term potentiation (LTP). These experiments used this observation to uncover the synaptic processes that stabilize the potentiation effect. Brief adenosine infusion blocked stimulation-induced actin polymerization within dendritic spines along with LTP itself in control rat hippocampal slices but not in those pretreated with the actin filament stabilizer jasplakinolide. Adenosine also blocked activity-driven phosphorylation of synaptic cofilin but not of synaptic p21-activated kinase (PAK). A search for the upstream origins of these effects showed that adenosine suppressed RhoA activity but only modestly affected Rac and Cdc42. A RhoA kinase (ROCK) inhibitor reproduced adenosine's effects on cofilin phosphorylation, spine actin polymerization, and LTP, whereas a Rac inhibitor did not. However, inhibitors of Rac or PAK did prolong LTP's vulnerability to reversal by latrunculin, a toxin which blocks actin filament assembly. Thus, LTP induction initiates two synaptic signaling cascades: one (RhoA-ROCK-cofilin) leads to actin polymerization, whereas the other (Rac-PAK) stabilizes the newly formed filaments.
PMID: 19596849
|
Chim N,McMath LM,Beeby M,Goulding CW
Department of Molecular Biology and Biochemistry, University of California, Irvine CA 92697, USA. elia.goulding@uci.edu.
|
Advances in Mycobacterium tuberculosis Structural Genomics: Investigating Potential Chinks in the Armor of a Deadly Pathogen.
Infect Disord Drug Targets. 2009 Oct 1;:
The waning effectiveness of established tuberculosis treatments due to the rise of multi and extensively drug-resistant strains of Mycobacterium tuberculosis, coupled with the synergism of HIV infection, demands basic research efforts to inform focused drug development programs. Structural genomics projects provide rich sources of information for the rational design of anti-tubercular drugs, aiming to exploit unique and novel protein features and interactions based on atomic resolution structures. This review compiles structures of M. tuberculosis proteins elucidated since January 2007 that are promising avenues for drug design, encompassing proteins involved with known and experimental anti-tuberculosis drugs, metabolism, dealing with the hostile environment of the host organism, and information processing.
PMID: 19594421
|
Schneider ML,Graham DJ
University of California at Irvine, CA, USA. Margaret.schneider@uci.edu
|
Personality, physical fitness, and affective response to exercise among adolescents.
Med Sci Sports Exerc. 2009 Apr;41(4):947-55
PURPOSE: Evidence shows that aspects of personality are associated with participation in physical activity. We hypothesized that, among adolescents, behavioral activation (BAS) and behavioral inhibition (BIS) systems would be associated with physical fitness (cardiovascular fitness and percent body fat), enjoyment of exercise, tolerance of and persistence in high-intensity exercise, and affective response to an acute exercise bout. METHODS: One hundred and forty-six healthy adolescents completed a cardiovascular fitness test, percent body fat assessment (dual-energy x-ray absorptiometer), and two 30-min cycle ergometer exercise tasks at moderate and hard intensities. Questionnaires evaluated BIS/BAS, enjoyment of exercise, and preference and tolerance for high-intensity activity. Affect in response to exercise was assessed using the Feeling Scale (FS) and the Activation Deactivation Adjective Check List (AD ACL). RESULTS: BIS was negatively correlated with cardiovascular fitness and tolerance for high-intensity exercise, and adolescents with high BIS scores reported more negative FS in response to exercise at both moderate and hard intensities. BAS was positively correlated with enjoyment of exercise, and adolescents with high BAS scores reported having more positive FS and higher energetic arousal on the AD ACL in response to moderate-intensity exercise. The association between BAS and affect was attenuated for the hard-intensity exercise task. CONCLUSION: These findings suggest that both the drive to avoid punishing stimuli (BIS) and the drive to approach rewarding stimuli (BAS) are related to the affective response to exercise. The BIS may be more strongly associated with fitness-related exercise behavior among adolescents than the BAS, whereas the BAS may play a relatively greater role in terms of subjective exercise enjoyment.
PMID: 19276837
|
Swanson JM,Volkow ND
Child Development Center Irvine, The Child Development Center, 19722 MacArthur Boulevard, Irvine, California 92612, USA. jmswanson@uci.edu
|
Psychopharmacology: concepts and opinions about the use of stimulant medications.
J Child Psychol Psychiatry. 2009 Jan;50(1-2):180-93
PMID: 19220601
|
Ferree NK,Cahill L
200 Bonney Research Laboratory, Center for the Neurobiology of Learning and Memory, University of California, Irvine, Irvine, CA 92697, United States. nferree@uci.edu
|
Post-event spontaneous intrusive recollections and strength of memory for emotional events in men and women.
Conscious Cogn. 2009 Mar;18(1):126-34
Spontaneous intrusive recollections (SIRs) follow traumatic events in clinical and non-clinical populations. To determine whether any relationship exists between SIRs and enhanced memory for emotional events, participants viewed emotional or neutral films, had their memory for the films tested two days later, and estimated the number of SIRs they experienced for each film. SIR frequency related positively to memory strength, an effect more pronounced in the emotional condition. These findings represent the first demonstration of a relationship between SIRs occurring after an emotional experience and subsequent memory strength for that experience. The results are consistent with the possibility that emotional arousal leads both to elevated SIR frequency and better memory, and that the covert rehearsal associated with SIRs enhances memory for emotional relative to neutral stimuli. Additional evidence of menstrual cycle influences on SIR incidence in female participants appears to merit consideration in future work.
PMID: 19131257
|
Jiang SC,Han J,He JW,Chu W
Civil and Environmental Engineering, University of California, 1367 SEII, Irvine, CA 92697, USA Tel.: +1 949-824-5527 E-mail: sjiang@uci.edu.
|
Evaluation of four cell lines for assay of infectious adenoviruses in water samples.
J Water Health. 2009 Jul;7(4):650-6
Human viral contamination in drinking and recreational waters poses health risks. The application of PCR-based molecular technology has advanced our knowledge of the occurrence and prevalence of human viruses in water; however, it has provided no information on viral viability and infectivity. Four human cell lines were compared for their sensitivity to different serotypes of human adenoviruses using the TCID(50) test. The sensitivity of each cell line varied with different serotypes of adenovirus. Human embryonic kidney cell line 293A and human lung carcinoma cell line A549 were the most sensitive, especially to enteric adenovirus 40 and 41. Plaque assay of primary sewage samples showed 293A can detect viral plaques in 7 of 13 primary sewage samples tested. Adenoviruses were also isolated using 293A from environmental water concentrates. Cloning and sequencing of environmental adenoviral isolates indentified them to be aligned with adenoviruses serotype 40 and serotype 5. The result of this study suggests that plaque assay with 293A cell line is suitable for detection of adenovirus in the aquatic environment. Combining this cell culture with molecular methods for viral assay in the aquatic environment will provide critical information for risk assessment.
PMID: 19590132
|
Dellinger TH,Monk BJ
Division of Gynecologic Oncology, Chao Family Comprehensive Cancer Center, University of California, Irvine Medical Center, Building 56, Suite 260, 101 The City Drive South, Orange County, CA 92868-3298, USA. tdelling@uci.edu
|
Systemic therapy for recurrent endometrial cancer: a review of North American trials.
Expert Rev Anticancer Ther. 2009 Jul;9(7):905-16
While early-stage endometrial cancer is highly curable after hysterectomy for the majority of patients afflicted with this disease, recurrent and metastatic endometrial cancer continues to pose a significant challenge. The median survival of women with advanced or recurrent uterine cancer on most recent clinical trials is only approximately 1 year. This review will discuss the developments of systemic therapy in recurrent endometrial cancer, focusing on North American trials, in particular those documenting recent progress in new drug developments, as well as the future of individualized treatment regimens.
PMID: 19589030
|
Willmott LJ,Monk BJ
University of California, Irvine, Department of Obstetrics and Gynecology, Chao Family Comprehensive Cancer Center, Orange, CA, USA. lwillmot@uci.edu
|
Cervical cancer therapy: current, future and anti-angiogensis targeted treatment.
Expert Rev Anticancer Ther. 2009 Jul;9(7):895-903
While the incidence of cervical cancer has declined significantly in the USA, ethnic disparities remain in terms of increased mortality and morbidity. Furthermore, this disease continues to be a significant burden on developing countries, with cervical cancer currently ranked as the second most common cause of cancer-related morbidity and the third most common cause of mortality worldwide. Treatment of cervical cancer has typically been viewed as surgical with possible adjuvant therapy versus initial radiotherapy and platinum-based chemotherapy. Prognosis and therapy for patients with recurrent disease is dependent upon the site of recurrence and ability to pursue curative therapy. This article will review the management of cervical cancer, including studies that have evaluated the treatment of distant metastasis or recurrent disease, as well as discussing the importance of angiogenesis and the use of therapies targeted against this phenomenon.
PMID: 19589029
|
Dwyer JB,McQuown SC,Leslie FM
Department of Pharmacology, Med Surge II, School of Medicine, University of California, Irvine, CA 92697, USA. jbdwyer@uci.edu
|
The dynamic effects of nicotine on the developing brain.
Pharmacol Ther. 2009 May;122(2):125-39
Nicotinic acetylcholine receptors (nAChRs) regulate critical aspects of brain maturation during the prenatal, early postnatal, and adolescent periods. During these developmental windows, nAChRs are often transiently upregulated or change subunit composition in those neural structures that are undergoing major phases of differentiation and synaptogenesis, and are sensitive to environmental stimuli. Nicotine exposure, most often via tobacco smoke, but increasingly via nicotine replacement therapy, has been shown to have unique effects on the developing human brain. Consistent with a dynamic developmental role for acetylcholine, exogenous nicotine produces effects that are unique to the period of exposure and that impact the developing structures regulated by acetylcholine at that time. Here we present a review of the evidence, available from both the clinical literature and preclinical animal models, which suggests that the diverse effects of nicotine exposure are best evaluated in the context of regional and temporal expression patterns of nAChRs during sensitive maturational periods, and disruption of the normal developmental influences of acetylcholine. We present evidence that nicotine interferes with catecholamine and brainstem autonomic nuclei development during the prenatal period of the rodent (equivalent to first and second trimester of the human), alters the neocortex, hippocampus, and cerebellum during the early postnatal period (third trimester of the human), and influences limbic system and late monoamine maturation during adolescence.
PMID: 19268688
|
Ayers FR,Cuccia DJ,Kelly KM,Durkin AJ
University of California-Irvine, Beckman Laser Institute, Irvine, California 92612, USA. fayers@uci.edu
|
Wide-field spatial mapping of in vivo tattoo skin optical properties using modulated imaging.
Lasers Surg Med. 2009 Aug;41(6):442-53
BACKGROUND AND OBJECTIVES: Modulated imaging is a new modality capable of wide-field, spatially resolved measurement of in vivo optical properties. Based on spatial light modulation, the method is inexpensive, non-contact, and allows spatial mapping of tissue absorption and reduced scattering coefficients at any wavelength between 450 and 1,100 nm. Currently, clinicians rely on qualitative visual inspection to guide parameter selection for laser-based tattoo removal. MI provides quantitative measurements of multi-colored tattooed skin which may help guide treatment and objectively assess response. STUDY DESIGN/MATERIALS AND METHODS: We have measured the spatially varying optical properties of multi-colored tattooed skin over a 50 mm x 50 mm field of view at wavelengths ranging from 650 to 970 nm using MI. These measurements were compared to a similar field of view of non-tattooed skin from an adjacent area. RESULTS: We have determined the differentiated optical properties in vivo of multi-colored tattooed skin versus non-tattooed skin. CONCLUSIONS: MI provides spatially resolved quantitative information with potential for quantitative assessment of response to treatment and may provide guidance for laser tattoo removal in the future.
PMID: 19588528
|
Metz M
Department of ORLIHNS, University of California-Irvine.
|
Ethics for Speech-Language Pathologists and Audiologists: An Illustrative Casebook.
Int J Audiol. 2009 Jul 8;:1
PMID: 19588277
|
Cooke J,Sullivan M,Barton EJ,Bullock JS,Carlberg RG,Gal-Yam A,Tollerud E
Center for Cosmology, Department of Physics and Astronomy, University of California, Irvine, California 92697-4574, USA. cooke@uci.edu
|
Type IIn supernovae at redshift z approximately 2 from archival data.
Nature. 2009 Jul 9;460(7252):237-9
Supernovae have been confirmed to redshift z approximately 1.7 (refs 1, 2) for type Ia (thermonuclear detonation of a white dwarf) and to z approximately 0.7 (refs 1, 3-5) for type II (collapse of the core of the star). The subclass type IIn (ref. 6) supernovae are luminous core-collapse explosions of massive stars and, unlike other types, are very bright in the ultraviolet, which should enable them to be found optically at redshifts z approximately 2 and higher. In addition, the interaction of the ejecta with circumstellar material creates strong, long-lived emission lines that allow spectroscopic confirmation of many events of this type at z approximately 2 for 3-5 years after explosion (ref. 14). Here we report three spectroscopically confirmed type IIn supernovae, at redshifts z = 0.808, 2.013 and 2.357, detected in archival data using a method designed to exploit these properties at z approximately 2. Type IIn supernovae directly probe the formation of massive stars at high redshift. The number found to date is consistent with the expectations of a locally measured stellar initial mass function, but not with an evolving initial mass function proposed to explain independent observations at low and high redshift.
PMID: 19587765
|
Meyskens FL
Chao Family Comprehensive Cancer Center and Department of Medicine, University of California Irvine, Irvine, California, USA. flmeyske@uci.edu
|
Food extracts for chemoprevention: quo vadis?
Cancer Prev Res (Phila Pa). 2009 Jul;2(7):608-10
PMID: 19584073
|
Kuppermann BD
Retina Service, Gavin Herbert Eye Institute, Department of Ophthalmology, University of California Irvine, Irvine, California 92697, USA. bdkupper@uci.edu
|
Drug delivery strategies for combination ophthalmic treatments.
Retina. 2009 Jun;29(6 Suppl):S24-6
The most significant obstacle to the combination of drug therapies in age-related macular degeneration (AMD) may be drug delivery. Although the posterior of the eye can be reached by intravitreal injections and implants, AMD is a chronic disease process that is likely to require prolonged or indefinite exposure to antiproliferative agents. In addition to the difficulty of repeat dosing in the vitreal space, ocular anatomy prohibits substantial drug volumes, a limitation further compounded when combining two or more agents. With low penetration to target areas of AMD, pathophysiology, and risk of significant systemic toxicity through systemic drug delivery, innovative strategies for introducing agents to their site of action may be the critical component of improved outcomes.
PMID: 19553793
|
Shin HW,Umber BJ,Meinardi S,Leu SY,Zaldivar F,Blake DR,Cooper DM
Department of Biomedical Engineering, University of California, Irvine, Irvine, CA 92697, USA. hyewons@uci.edu
|
Acetaldehyde and hexanaldehyde from cultured white cells.
J Transl Med. 2009;7:31
BACKGROUND: Noninvasive detection of innate immune function such as the accumulation of neutrophils remains a challenge in many areas of clinical medicine. We hypothesized that granulocytes could generate volatile organic compounds. METHODS: To begin to test this, we developed a bioreactor and analytical GC-MS system to accurately identify and quantify gases in trace concentrations (parts per billion) emitted solely from cell/media culture. A human promyelocytic leukemia cell line, HL60, frequently used to assess neutrophil function, was grown in serum-free medium. RESULTS: HL60 cells released acetaldehyde and hexanaldehyde in a time-dependent manner. The mean +/- SD concentration of acetaldehyde in the headspace above the cultured cells following 4-, 24- and 48-h incubation was 157 +/- 13 ppbv, 490 +/- 99 ppbv, 698 +/- 87 ppbv. For hexanaldehyde these values were 1 +/- 0.3 ppbv, 8 +/- 2 ppbv, and 11 +/- 2 ppbv. In addition, our experimental system permitted us to identify confounding trace gas contaminants such as styrene. CONCLUSION: This study demonstrates that human immune cells known to mimic the function of innate immune cells, like neutrophils, produce volatile gases that can be measured in vitro in trace amounts.
PMID: 19402909
|
Constantinescu CC,Mukherjee J
Department of Psychiatry and Human Behavior, University of California Irvine, Irvine, CA, USA. constant@uci.edu
|
Performance evaluation of an Inveon PET preclinical scanner.
Phys Med Biol. 2009 May 7;54(9):2885-99
We evaluated the performance of an Inveon preclinical PET scanner (Siemens Medical Solutions), the latest MicroPET system. Spatial resolution was measured with a glass capillary tube (0.26 mm inside diameter, 0.29 mm wall thickness) filled with (18)F solution. Transaxial and axial resolutions were measured with the source placed parallel and perpendicular to the axis of the scanner. The sensitivity of the scanner was measured with a (22)Na point source, placed on the animal bed and positioned at different offsets from the center of the field of view (FOV), as well as at different energy and coincidence windows. The noise equivalent count rates (NECR) and the system scatter fraction were measured using rat-like (Phi = 60, L = 150 mm) and mouse-like (Phi = 25 mm, L = 70 mm) cylindrical phantoms. Line sources filled with high activity (18)F (>250 MBq) were inserted parallel to the axes of the phantoms (13.5 and 10 mm offset). For each phantom, list-mode data were collected over 24 h at 350-650 keV and 250-750 keV energy windows and 3.4 ns coincidence window. System scatter fraction was measured when the random event rates were below 1%. Performance phantoms consisting of cylinders with hot rod inserts filled with (18)F were imaged. In addition, we performed imaging studies that show the suitability of the Inveon scanner for imaging small structures such as those in mice with a variety of tracers. The radial, tangential and axial resolutions at the center of FOV were 1.46 mm, 1.49 and 1.15 mm, respectively. At a radial offset of 2 cm, the FWHM values were 1.73, 2.20 and 1.47 mm, respectively. At a coincidence window of 3.4 ns, the sensitivity was 5.75% for EW = 350-650 keV and 7.4% for EW = 250-750 keV. For an energy window of 350-650 keV, the peak NECR was 538 kcps at 131.4 MBq for the rat-like phantom, and 1734 kcps at 147.4 MBq for the mouse-like phantom. The system scatter fraction values were 0.22 for the rat phantom and 0.06 for the mouse phantom. The Inveon system presents high image resolution, low scatter fraction values and improved sensitivity and count rate performance.
PMID: 19384008
|
Elmore E,Lao XY,Kapadia R,Redpath JL
Department of Radiation Oncology and Chao Family Comprehensive Cancer Center, University of California Irvine, Irvine, California 92967, USA.
|
Threshold-type dose response for induction of neoplastic transformation by 1 GeV/nucleon iron ions.
Radiat Res. 2009 Jun;171(6):764-70
Neoplastic transformation of HeLa x skin fibroblast human hybrid cells by doses of 1 GeV/nucleon iron ions in the range 1 cGy to 1 Gy to exposed cultures has been examined. The data indicate a threshold-type dose-response curve with no increase in transformation frequency until doses above 20 cGy. At doses <10 cGy, not all exposed cells receive a direct traversal of an iron-ion track core, but all exposed cells receive up to several mGy of low-LET radiation associated with the delta-ray penumbra. It is proposed that the threshold-type response seen is a consequence of an adaptive response associated with the delta-ray exposure. For comparison purposes, the dose response for (137)Cs gamma rays over the same dose range was examined using the same experimental procedure. As we have shown previously, the dose response for (137)Cs gamma radiation was J-shaped. The iron ions were 1.5 to 1.7 times more biologically effective than the gamma radiation over the dose range examined.
PMID: 19580483
|
Fu LW,Longhurst JC
Department of Medicine, University of California, Irvine, CA 92697, USA. lwfu@uci.edu
|
Electroacupuncture modulates vlPAG release of GABA through presynaptic cannabinoid CB1 receptors.
J Appl Physiol. 2009 Jun;106(6):1800-9
Previous studies have demonstrated that electroacupuncture (EA) attenuates sympathoexcitatory reflex responses by activating a long-loop pathway involving the hypothalamic arcuate nucleus (ARC), midbrain ventrolateral periaqueductal gray (vlPAG), and rostral ventrolateral medulla (rVLM). Neurons in the ARC provide excitatory input to the vlPAG, whereas the vlPAG inhibits neuronal activity in the rVLM. gamma-Aminobutyric acid (GABA) and glutamate (Glu) have been identified in the vlPAG. Endocannabinoids (ECs), acting as atypical neurotransmitters, inhibit the release of both neurotransmitters in the hypothalamus and midbrain through a presynaptic cannabinoid type 1 (CB(1)) receptor mechanism. The EC system has been observed in the dorsal but not in the vlPAG. Since it is uncertain whether ECs influence GABA and Glu in the vlPAG, the present study tested the hypothesis that EA modulates the release of these neurotransmitters in the vlPAG through a presynaptic CB(1) receptor mechanism. We measured the release of GABA and Glu simultaneously by using HPLC to assess samples collected with microdialysis probes inserted unilaterally into the vlPAG of intact anesthetized rats. Twenty-eight min of EA (2 Hz, 2-4 mA, 0.5 ms) at the P5-6 acupoints reduced the release of GABA by 39% during EA and by 44% 15 min after EA. Thirty-five minutes after EA, GABA concentrations returned to pre-EA levels. In contrast, sham EA did not change the vlPAG GABA concentration. Blockade of CB(1) receptors with AM251, a selective CB(1) receptor antagonist, reversed the EA-modulated changes in GABA concentration, whereas microinjection of vehicle into the vlPAG did not alter EA-modulated GABA changes. In addition, we observed no changes in the vlPAG Glu concentrations during EA, although the baseline concentration of Glu was much higher than that of GABA (3,541 +/- 373 vs. 33.8 +/- 8.7 nM, Glu vs. GABA). These results suggest that EA modulates the sympathoexcitatory reflex responses by decreasing the release of GABA, but not Glu, in the vlPAG, most likely through a presynaptic CB(1) receptor mechanism.
PMID: 19359606
|
Tjen-A-Looi SC,Li P,Longhurst JC
School of Medicine, University of California, Irvine, CA 92697-4075, USA. stjenalo@uci.edu
|
Processing cardiovascular information in the vlPAG during electroacupuncture in rats: roles of endocannabinoids and GABA.
J Appl Physiol. 2009 Jun;106(6):1793-9
A long-loop pathway, involving the hypothalamic arcuate nucleus (ARC), ventrolateral periaqueductal gray (vlPAG), and the rostral ventrolateral medulla (rVLM), is essential in electroacupuncture (EA) attenuation of sympathoexcitatory cardiovascular reflex responses. The ARC provides excitatory input to the vlPAG, which, in turn, inhibits neuronal activity in the rVLM. Although previous studies have shown that endocannabinoid CB(1) receptor activation modulates gamma-aminobutyric acid (GABA)-ergic and glutamatergic neurotransmission in the dorsolateral PAG in stress-induced analgesia, an important role for endocannabinoids in the vlPAG has not yet been observed. We recently have shown (Fu LW, Longhurst JC. J Appl Physiol; doi:10.1152/japplphysiol.91648.2008) that EA reduces the local vlPAG concentration of GABA, but not glutamate, as measured with high-performance liquid chromatography from extracellular samples collected by microdialysis. We, therefore, hypothesized that, during EA, endocannabinoids, acting through CB(1) receptors, presynaptically inhibit GABA release to disinhibit the vlPAG and ultimately modulate excitatory reflex blood pressure responses. Rats were anesthetized, ventilated, and instrumented to measure heart rate and blood pressure. Gastric distention-induced blood pressure responses of 18 +/- 5 mmHg were reduced to 6 +/- 1 mmHg by 30 min of low-current, low-frequency EA applied bilaterally at pericardial P 5-6 acupoints overlying the median nerves. Like EA, microinjection of the fatty acid amide hydrolase inhibitor URB597 (0.1 nmol, 50 nl) into the vlPAG to increase endocannabinoids locally reduced the gastric distention cardiovascular reflex response from 21 +/- 5 to 3 +/- 4 mmHg. This inhibition was reversed by pretreatment with the GABA(A) antagonist gabazine (27 mM, 50 nl), suggesting that endocannabinoids exert their action through a GABAergic receptor mechanism in the vlPAG. The EA-related inhibition from 18 +/- 3 to 8 +/- 2 mmHg was reversed to 14 +/- 2 mmHg by microinjection of the CB(1) receptor antagonist AM251 (2 nmol, 50 nl) into the vlPAG. Pretreatment with gabazine eliminated reversal following CB(1)-receptor blockade. Thus EA releases endocannabinoids and activates presynaptic CB(1) receptors to inhibit GABA release in the vlPAG. Reduction of GABA release disinhibits vlPAG cells, which, in turn, modulate the activity of rVLM neurons to attenuate the sympathoexcitatory reflex responses.
PMID: 19325030
|
Vardo-Zalik AM,Ford AF,Schall JJ
University of California at Irvine, 92697, USA. avardoza@uci.edu
|
Detecting number of clones, and their relative abundance, of a malaria parasite (Plasmodium mexicanum) infecting its vertebrate host.
Parasitol Res. 2009 Jul;105(1):209-15
Microsatellites, short tandem repeats of nucleotides in the genome, are useful markers to detect clonal diversity within Plasmodium infections. However, accuracy in determining number of clones and their relative proportions based on standard genetic analyzer instruments is poorly known. DNA extracted from lizards infected with a malaria parasite, Plasmodium mexicanum, provided template to genotype the parasite based on three microsatellite markers. Replicate genotyping of the same natural infections demonstrated strong repeatability of data from the instrument. Mixing DNA extracted from several infected lizards simulated mixed-clone infections with known clonal diversity and relative proportions of clones (N = 56 simulations). The instrument readily detected at least four alleles (clones), even when DNA concentrations among clones differed up to tenfold, but alleles of similar size can be missed because they fall within the "stutter" artifact, and rarely does an allele fail to be detected. For simulations of infections that changed their relative proportions over time, changes in relative peak heights on the instrument output closely followed the known changes in relative proportions. Such data are useful for a broad range of studies on the ecology of malaria parasites.
PMID: 19277713
|
Choi B,Bjorner JB,Ostergren PO,Clays E,Houtman I,Punnett L,Rosengren A,De Bacquer D,Ferrario M,Bilau M,Karasek R
Center for Occupational and Environmental Health, University of California Irvine, Irvine, CA 92617, USA. b.choi@uci.edu
|
Cross-language differential item functioning of the job content questionnaire among European countries: the JACE study.
Int J Behav Med. 2009;16(2):136-47
BACKGROUND: Little is known about cross-language measurement equivalence of the job content questionnaire (JCQ) PURPOSE: The purposes of this study were to assess the extent of cross-language differential item functioning (DIF) of the 27 JCQ items in six languages (French, Dutch, Belgian-French, Belgian-Dutch (Flemish), Italian, and Swedish) from six European research centers and to test whether its effects on the scale-level mean comparisons among the centers were substantial or not. METHOD: A partial gamma coefficient method was used for statistical DIF analyses where the Flemish JCQ was the reference for other language versions. Additionally, equivalence between the Flemish and Dutch translations was subjected to a judgmental review. RESULTS: On average, 36% to 39% of the total tested items appeared to be cross-language DIF items in the statistical analyses. The judgmental review indicated that half of the DIF items may be associated with translation difference. The impacts of the DIF items on the mean comparisons of the JCQ scales between the centers were non-trivial: underestimated skill discretion (Milan), underestimated decision authority (Leiden), underestimated psychological demands (Milan women), and incomparable coworker support (Gothenburg 95). CONCLUSION: Cross-language DIF of the JCQ among European countries should be considered in international comparative studies on psychosocial job hazards using JCQ scales.
PMID: 19575297
|
Bailey SR
University of California, Department of Sociology, 3151 Social Science Plaza, Irvine, California 92697-5100, USA. bailey@uci.edu
|
Unmixing for race making in Brazil.
AJS. 2008 Nov;114(3):577-614
This article analyzes race-targeted policy in Brazil as both a political stake and a powerful instrument in an unfolding classificatory struggle over the definition of racial boundaries. The Brazilian state traditionally embraced mixed-race classification, but is adopting racial quotas employing a black/white scheme. To explore potential consequences of that turn for beneficiary identification and boundary formation, the author analyzes attitudinal survey data on race-targeted policy and racial classification in multiple formats, including classification in comparison to photographs. The results show that almost half of the mixed-race sample, when constrained to dichotomous classification, opts for whiteness, a majority rejects mixed-race individuals for quotas, and the mention of quotas for blacks in a split-ballot experiment nearly doubles the percentage choosing that racial category. Theories of how states make race emphasize the use of official categories to legislate exclusion. In contrast, analysis of the Brazilian case illuminates how states may also make race through policies of official inclusion.
PMID: 19569393
|
|
first | prev 10 | prev | 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 | 10 | next | next 10 | last |
|
back
