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Intermittent Injection (intermittent + injection)

Distribution by Scientific Domains
Medical Sciences50%

Selected Abstracts

ChemInform Abstract: Persistent Photoconductivity under Atmospheric Pressure in Uniformly Doped n-GaAs Prepared by Intermittent Injection of (CH3)3Ga/AsH3.

CHEMINFORM, Issue 2 2002
Yutaka Oyama
Abstract ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a "Full Text" option. The original article is trackable via the "References" option. [source]

Chronic Intermittent Injections of High-Dose Ethanol During Adolescence Produce Metabolic, Hypnotic, and Cognitive Tolerance in Rats

ALCOHOLISM, Issue 10 2003
Janelle M. Silvers
Background: Many humans are first exposed to ethanol during adolescence, the time at which they are most likely to binge drink ethanol. Chronic intermittent ethanol (CIE) exposure produces ethanol tolerance in adolescent rodents. Recent studies suggested that adolescent animals administered CIE experienced increased cognitive impairment following an ethanol challenge. These studies further explore development of ethanol tolerance caused by CIE in adolescence, and whether CIE during adolescence leads to altered ethanol response in adulthood. Methods: Beginning postnatal day (P) 30, adolescent rats were administered 5.0 g/kg ethanol or saline every 48 hours for 20 days. In experiment I, animals were tested for differential weight gain. In experiment II, loss of righting reflex (LORR) was observed after each injection, then at completion of pretreatment all animals were tested with 5.0 g/kg ethanol and LORR was observed. In experiment III, blood ethanol levels were observed and elimination rates calculated after the first and fifth pretreatments. All animals were tested with 5.0 g/kg at completion of pretreatment and elimination rates were recalculated. In experiment IV, animals were trained on the spatial version of the Morris Water Maze Task (MWMT) on non-treatment days. Following completion of pretreatment and training, animals were tested after receiving an ethanol (1.0, 1.5, or 2.0 g/kg), or saline. Tests for experiments II, III, and IV were repeated in the same animals following 12 ethanol-free days. Results: Chronic intermittent ethanol exposure during adolescence caused differential weight gain (experiment I). Adolescent rats developed tolerance to ethanol-induced LORR (experiment II) and metabolic tolerance to ethanol (experiment III). This tolerance was seen after 12 ethanol-free days. CIE also attenuated ethanol-induced spatial memory deficits in the MWMT (experiment IV). This effect was not long-lasting. Conclusions: Following CIE pretreatment during adolescence, tolerance developed to the hypnotic and cognitive impairing effects of ethanol, along with increased metabolic rate and decreased weight gain. These results further emphasize the ability of CIE to produce a variety of effects during adolescence, some having long-lasting consequences. [source]

Tunneling in quantum confined GaAs ultrashallow sidewall tunnel junctions

PHYSICA STATUS SOLIDI (C) - CURRENT TOPICS IN SOLID STATE PHYSICS, Issue 3 2006
Takeo Ohno
Abstract Temperature dependence of current-voltage (I - V ) characteristics of quantum-confined GaAs ultra-shallow sidewall p+n+ tunnel junctions has been investigated. The sidewall tunnel junctions with junction depths ranging from 5 nm to 50 nm were achieved by the combination of intermittent injection of TEG/AsH3 in an ultra high vacuum and a wet etching process of the GaAs growth layer. From the I - V results, abrupt negative differential resistances (NDR) were observed, which relate to direct/indirect tunneling and sub-band formation. The change in the number instances of NDR and their voltage positions also depended on the junction depth. Mechanisms of tunneling in the present sidewall tunnel junction will be discussed from the point of the sub-band formation in conduction bands. (© 2006 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source]

Triptan-induced latent sensitization: A possible basis for medication overuse headache

ANNALS OF NEUROLOGY, Issue 3 2010
Milena De Felice PhD
Objective Identification of the neural mechanisms underlying medication overuse headache resulting from triptans. Methods Triptans were administered systemically to rats by repeated intermittent injections or by continuous infusion over 6 days. Periorbital and hind paw sensory thresholds were measured to detect cutaneous allodynia. Immunofluorescent histochemistry was employed to detect changes in peptidic neurotransmitter expression in identified dural afferents. Enzyme-linked immunoabsorbent assay was used to measure calcitonin gene-related peptide (CGRP) levels in blood. Results Sustained or repeated administration of triptans to rats elicited time-dependent and reversible cutaneous tactile allodynia that was maintained throughout and transiently after drug delivery. Triptan administration increased labeling for CGRP in identified trigeminal dural afferents that persisted long after discontinuation of triptan exposure. Two weeks after triptan exposure, when sensory thresholds returned to baseline levels, rats showed enhanced cutaneous allodynia and increased CGRP in the blood following challenge with a nitric oxide donor. Triptan treatment thus induces a state of latent sensitization characterized by persistent pronociceptive neural adaptations in dural afferents and enhanced responses to an established trigger of migraine headache in humans. Interpretation Triptans represent the treatment of choice for moderate and severe migraine headaches. However, triptan overuse can lead to an increased frequency of migraine headache. Overuse of these medications could induce neural adaptations that result in a state of latent sensitization, which might increase sensitivity to migraine triggers. The latent sensitization could provide a mechanistic basis for the transformation of migraine to medication overuse headache. ANN NEUROL 2010;67:325,337 [source]