Posttraumatic stress disorder (PTSD) is a serious mental health condition that affects some individuals who have witnessed or experienced a life-threatening or traumatic event. An enhanced or exaggerated acoustic startle response (ASR), reflecting heightened sensitivity to unexpected, loud sound, is a hallmark symptom of PTSD. Antidepressant medications, such as sertraline, are first-line pharmacotherapeutic agents in the treatment of PTSD, but concerns about potential side effects or taking synthetic drugs prompt discovery of naturalistic therapeutic agents.
View Article and Find Full Text PDFAn aspect of mycotoxin biosynthesis that remains unclear is its relationship with the cellular management of reactive oxygen species (ROS). Here we conduct a comparative study of the total ROS production in the wild-type strain (SU-1) of the plant pathogen and aflatoxin producer, , and its mutant strain, AFS10, in which the aflatoxin biosynthesis pathway is blocked by disruption of its pathway regulator, . We show that SU-1 demonstrates a significantly faster decrease in total ROS than AFS10 between 24 h to 48 h, a time window within which aflatoxin synthesis is activated and reaches peak levels in SU-1.
View Article and Find Full Text PDFBackground: Long noncoding RNAs (lncRNAs) are an emerging class of relatively underexplored oncogenic molecules with biological and clinical significance. Current inadequacies for stratifying patients with aggressive disease presents a strong rationale to systematically identify lncRNAs as clinical predictors in localized prostate cancer.
Objective: To identify RNA biomarkers associated with aggressive prostate cancer.
Overt sexual prejudice is declining, but heterosexuals who report little to no prejudice may still harbor subtle biases against gay men and lesbians. We examined implicit prejudice in a sample of 37 heterosexual college students who reported little or no sexual prejudice, using the Affect Misattribution Procedure (AMP) and psychophysiological measures of affect. Skin conductance, heart rate, and facial electromyographic responses were recorded as participants viewed photos of mixed- and same-sex couples kissing and rated them on valence, arousal, and disgustingness.
View Article and Find Full Text PDFFungal pathogens need regulated mechanical and morphological fine-tuning for pushing through substrates to meet their metabolic and functional needs. Currently very little is understood on how coordinated colony level morphomechanical modifications regulate their behavior. This is due to an absence of a method that can simultaneously map, quantify, and correlate global fluctuations in physical properties of the expanding fungal colonies.
View Article and Find Full Text PDFPrevious studies have shown that social rejection leads to impaired performance on a variety of tasks that require self control, including the Stroop color-word interference task; however, mechanisms underlying the effect remain to be elucidated. We attempted to clarify the effects of social rejection on self control resources by measuring event-related potentials (ERPs) during a computerized Stroop test. Stroop performance and ERPs from 54 participants in rejected, control, and accepted groups were analyzed.
View Article and Find Full Text PDFModafinil is a psychostimulant approved for treating excessive sleepiness in adults; off-label uses (e.g., treatment of cognitive impairment in schizophrenia, ADHD and age-related dementias) are currently being explored.
View Article and Find Full Text PDFAuditory neuropathy is a hearing disorder characterized by normal function of outer hair cells, evidenced by intact cochlear microphonic (CM) potentials and otoacoustic emissions (OAEs), with absent or severely dys-synchronized auditory brainstem responses (ABRs). To determine if selective lesions of inner hair cells (IHCs) and auditory nerve fibers (ANFs) can account for these primary clinical features of auditory neuropathy, we measured physiological responses from chinchillas with large lesions of ANFs (about 85%) and IHCs (45% loss in the apical half of the cochlea; 73% in the basal half). Distortion product OAEs and CM potentials were significantly enhanced, whereas summating potentials and compound action potentials (CAPs) were significantly reduced.
View Article and Find Full Text PDFThe goals were to study the physiological effects of auditory nerve myelinopathy in chinchillas and to test the hypothesis that myelin abnormalities could account for auditory neuropathy, a hearing disorder characterized by absent auditory brainstem responses (ABRs) with preserved outer hair cell function. Doxorubicin, a cytotoxic drug used as an experimental demyelinating agent, was injected into the auditory nerve bundle of 18 chinchillas; six other chinchillas were injected with vehicle alone. Cochlear microphonics, compound action potentials (CAPs), inferior colliculus evoked potentials (IC-EVPs), cubic distortion product otoacoustic emissions and ABRs were recorded before and up to 2 months after injection.
View Article and Find Full Text PDFCarboplatin produces progressive damage to auditory nerve fibers, spiral ganglion neurons (SGNs) and inner hair cells (IHC) in the chinchilla cochlea but leaves outer hair cells intact. Within 1 h after injection, many afferent terminals beneath IHCs and myelin lamellae surrounding SGN processes are vacuolated. One day after injection, approximately half of the nerve fibers are missing.
View Article and Find Full Text PDFPurpose: To determine whether children with a nonverbal learning disability (NVLD) have a higher incidence of auditory processing disorder (APD), especially in the tolerance-fading memory type of APD, and what associations could be found between performance on neuropsychological, intellectual, memory, and academic measures and APD.
Method: Eighteen children with NVLD ranging in age from 6 to 18 years received a central auditory processing test battery to determine incidence and subtype of APD. Psychological measures for assessment of NVLD included the Wechsler Scales, Wide Range Assessment of Memory and Learning, and Wechsler Individual Achievement Test.
Contemp Top Lab Anim Sci
November 2005
Thyroid and embedded parathyroid glands were surgically removed (thyroparathyroidectomized) from adult chinchillas (Chinchilla laniger) to create an animal model of hypothyroidism. Thyroxine (T4) levels were measured at the time of surgery and one or two times after surgery from 10 thyroparathyroidectomized chinchillas and five sham controls to establish baseline serum T4 levels and to assess the degree and duration of hypothyroidism in this animal model. Baseline T4 levels ranged from 3.
View Article and Find Full Text PDFDBA/2J (D2) mice, which exhibit very early progressive sensorineural hearing loss, were treated nightly with an augmented acoustic environment (AAE) initiated before the onset of hearing, and consisting of repetitive bursts of a 70-dB sound pressure level (SPL), 4-25 kHz noise band. At 55 days of age, AAE-treated mice exhibited less elevation of auditory brainstem response thresholds, fewer missing hair cells, and greatly reduced loss of anteroventral cochlear nucleus (AVCN) volume and neuron number compared to untreated control mice. It was hypothesized that the central neuroprotective effect was associated with increased afferent input to AVCN neurons evoked by the AAE as well as a healthier cochlea.
View Article and Find Full Text PDFVitamin C (ascorbate) is a water-soluble, low molecular weight antioxidant that works in conjunction with glutathione and other cellular antioxidants, and is effective against a variety of reactive oxygen species, including superoxide and hydroxyl radicals that have been implicated in the etiology of noise-induced hearing loss (NIHL). Whereas most animals can manufacture their own vitamin C, humans and a few other mammals such as guinea pigs lack the terminal enzyme for vitamin C synthesis and must obtain it from dietary sources. To determine if susceptibility to NIHL could be influenced by manipulating dietary levels of vitamin C, albino guinea pigs were raised for 35 days on a diet with normal, supplemented or deficient levels of ascorbate, then exposed to 4 kHz octave band noise at 114 dB SPL for 6 h to induce permanent threshold shifts (PTS) of the scalp-recorded auditory brainstem response.
View Article and Find Full Text PDFSome forms of ototoxicity appear to be mediated primarily by the superoxide radical; however, the exact role the superoxide radical plays in cochlear damage is not well understood because most ototoxic drugs produce multiple reactive oxygen species. To characterize the role of the superoxide radical in cochlear damage and the protective effect of compounds that inactivate superoxide, we treated mouse cochlear organotypic cultures for 24 h with paraquat, an herbicide that produces high levels of superoxide. M40403, a highly specific, nonpeptidyl mimetic of superoxide dismutase, was added to some cultures to inactivate the superoxide radical generated by paraquat.
View Article and Find Full Text PDFEthacrynic acid (EA) is known to interact with aminoglycoside antibiotics such as gentamicin (GM). In the chinchilla, co-administration of GM and EA can produce hair cell lesions ranging from a small loss of outer hair cells (OHCs) in the base of the cochlea to complete destruction of all hair cells, depending on dosing parameters. Although hair cell loss has been characterized, little is known about the fate of efferent fibers or spiral ganglion neurons (SGNs) in this model.
View Article and Find Full Text PDFA key factor in the well-known interaction between ethacrynic acid (EA) and aminoglycoside antibiotics (AABs) is disruption of the blood-labyrinth barrier (BLB), leading to rapid entry of EA and AABs into the cochlear fluids. The idea that the blood-labyrinthine fluid concentration gradient might be utilized in a protective manner was tested in the current experiment. We hypothesized that administering EA when gentamicin (GM) levels are higher in the cochlea than in the blood might actually reduce cochlear damage by permitting efflux of GM from the cochlear fluids into the bloodstream, down a concentration gradient and across a temporarily disrupted BLB.
View Article and Find Full Text PDFThe protective effects of glutathione monoethylester (GEE) and GEE in combination with R-N6-phenylisopropyladenosine (R-PIA) were evaluated in the chinchilla when exposed to impulse (145 dB pSPL) or continuous (105 dB SPL, 4 kHz OB) noise. Six groups of 10 chinchillas were used as subjects. Before exposure to noise, the subjects were anesthetized, a 30 microl drop of drug was placed on the round window (GEE [50, 100, 150 mM], GEE 50 mM and R-PIA).
View Article and Find Full Text PDFIn spite of the differences in the nature of the insult, the hearing loss from ototoxic drugs and noise exposure share a number of similarities in cochlear pathology. This paper explores the common factors between noise-induced hearing loss and ototoxicity by experimentally manipulating cochlear glutathione (GSH). In the first experiment, chinchillas were treated with a drop of saline (50 &mgr;l) on the round window of one ear and a drop of buthionine sulfoximine (BSO, 50 &mgr;l of 200 mM) on the other ear.
View Article and Find Full Text PDFOne consequence of noise exposure is increased production of reactive oxygen species (ROS), such as superoxide, hydrogen peroxide, and hydroxyl radicals, in the cochlea. ROS can cause oxidative damage to diverse cellular components, including membranes, proteins, and DNA, if they are not "neutralised" by antioxidant defences. Two important enzymes of the cochlear antioxidant defense system are cytosolic copper/zinc superoxide dismutase (SOD1) and selenium-dependent glutathione peroxidase (GPx1).
View Article and Find Full Text PDFAcoustic overstimulation produces many anatomical, biochemical and physiological changes in the inner ear. However, the changes in gene expression that underlie these biological changes are poorly understood. Our approach to investigating this problem is to use gene microarrays to measure the changes in gene expression in the chinchilla inner ear following a 3 h or 6 h noise exposure (95 dB SPL, 707-1414 Hz).
View Article and Find Full Text PDFGentamicin, an aminoglycoside antibiotic, and cisplatin, a platinum-based anticancer drug, are two commonly used clinical drugs with ototoxic side effects. The ototoxicity of gentamicin and cisplatin has been linked to the production of reactive oxygen species (ROS), although the specific ROS pathways have not been identified. One ROS that might play a role in ototoxicity is the superoxide radical, which is enzymatically dismutated to molecular oxygen and hydrogen peroxide by endogenous superoxide dismutase (SOD) enzymes.
View Article and Find Full Text PDFAlthough it is well known that ethacrynic acid (EA) can enhance gentamicin (GM) ototoxicity, there has been no systematic study of the relationship between dosing parameters and inner ear pathology. We examined the effects of two parameters, GM dose and time delay between GM and EA administration, on cochlear and vestibular hair cell loss in chinchillas. 'No delay' groups received one injection of GM (125, 40, 20, or 10 mg/kg i.
View Article and Find Full Text PDFThe mechanisms underlying the ototoxicity of ethacrynic acid (EA) are not fully understood. Previous studies have focused on morphologic and enzymatic changes in the stria vascularis. The current experiment shows that one of the earliest effects of EA is ischemia, resulting from impaired blood flow in vessels supplying the lateral wall of the cochlea.
View Article and Find Full Text PDFNeurons containing gamma aminobutyric acid (GABA) are widely distributed throughout the primary auditory cortex (AI). We investigated the effects of endogenous GABA by comparing response properties of 110 neurons in chinchilla AI before and after iontophoresis of bicuculline, a GABA(A) receptor antagonist, and/or CGP35348, a GABA(B) receptor antagonist. GABA(A) receptor blockade significantly increased spontaneous and driven discharge rates, dramatically decreased the thresholds of many neurons, and constricted the range of thresholds across the neural population.
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