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排序方式: 共有363条查询结果,搜索用时 15 毫秒
91.
Abbassy MM Shaheen HI Dykstra EA Beavers GM Hoel DF Hanafi HA Afifi MM Ibrahim MO Karim KA 《The Egyptian journal of immunology / Egyptian Association of Immunologists》2007,14(1):43-54
Insecticide use continues to be the primary control strategy to reduce insect vector populations. Concerns about insecticide resistance in target organisms, environmental degradation, and possible deleterious impact on human health have led researchers to seek a variety of alternative control strategies. We tested a relatively new method for controlling mosquitoes using host immune response. New Zealand White (NZW) rabbits (Oryctolagus cuniculus) were immunized with salivary gland (SGE), midgut (MGE), or ovary (OVE) extracts from female Culex pipiens L. Immunized rabbits were then exposed to unfed adult mosquitoes which were subsequently observed for changes in survival, fecundity, and hatch success. Parents that fed upon MGE- (P<0.001), SGE- (P<0.018) and OVE- (P<0.018) immunized rabbits experienced significantly higher mortality within 48 hours than parents fed on control rabbits. Midgut extract elicited the strongest effects upon survival (P<0.001), oviposition activity (P<0.001), and hatch success (P<0.001) in the parent generation. Survival (P<0.018), oviposition activity (P<0.001), and hatch success (P<0.001) were likewise strongly reduced in parents fed on SGE-immunized rabbits. Ovary extract-fed parents experienced less pronounced, but significant reductions, in survival (P<0.018) and hatch success (P<0.034). Surviving progeny were most strongly impacted by feeding upon MGE-immunized rabbits. Our study suggests that manipulating host immune response may be a suitable technique for reducing Cx. pipiens mosquito survival and fecundity, and subsequently the potential risk of disease transmission by this species. 相似文献
92.
Role of morphine maintenance dose in the development of tolerance and its attenuation by an NMDA receptor antagonist 总被引:1,自引:0,他引:1
Rationale: Current research shows that N-methyl-d-aspartate (NMDA) receptor antagonists attenuate the development of morphine tolerance in rodent antinociceptive assays. Objective: The purpose of this study was to determine the role of morphine maintenance dose in the attenuation of morphine tolerance
by the competitive NMDA receptor antagonist, LY235959. Methods: A rat warm-water tail-withdrawal procedure was used to measure the antinociceptive effects of morphine and LY235959. In this
procedure, the distal 8 cm of each rat’s tail is immersed in 40° (non-noxious) and 55°C (noxious) water, and the latency to
remove the tail is recorded. Results: Morphine (0.3–10 mg/kg, SC) produced dose-dependent increases in tail-withdrawal latencies from the 55°C water. Following
determination of the morphine dose-effect curves, rats were administered chronically one of three doses of morphine (10, 20,
or 40 mg/kg) either alone or in combination with LY235959 (1.0, 3.0, or 5.6 mg/kg, SC) twice daily for 7 days. Chronic administration
of 10, 20, and 40 mg/kg morphine produced rightward shifts in the morphine dose-effect curves of approximately 3-, 6-, and
12-fold, respectively. When LY235959 (1.0–5.6 mg/kg) was co-administered with 10 mg/kg morphine, the development of morphine
tolerance was attenuated in a dose-dependent manner, with complete prevention observed following 3.0 mg/kg LY235959. LY235959
(1.0, 3.0 mg/kg) also attenuated the development of tolerance to 20 and 40 mg/kg morphine; however, tolerance was not completely
prevented. Administering 3.0 mg/kg LY235959 along with 20 and 40 mg/kg morphine was functionally equivalent to treating rats
with half the amount of morphine. Conclusion: These data suggest that the maintenance dose of morphine, and thus the magnitude of tolerance, can determine the effectiveness
of an NMDA receptor antagonist to attenuate morphine tolerance.
Received: 5 April 1999 / Final version: 23 July 1999 相似文献
93.
Chauret C Volk C Stover L Dykstra TS Andrews RC Gagnon GA 《Journal of water and health》2005,3(4):359-369
This research was conducted to assess the impact of various disinfectants on bacterial water quality within model distribution systems (i.e. annular reactors). After colonization with non-disinfected water, annular reactors were treated with relatively low doses of chlorine (0.4 mg/l), chlorine dioxide (0.15 mg/l), or chloramines (0.9 mg/l). Under the tested conditions, bacterial inactivation varied as a function of disinfectant type (ranking by efficiency per mg of oxidant: ClO2 > Cl2 > ClNH2) and sample type (bulk water vs. biofilm). Depending on the disinfectant, the log inactivation of suspended and attached bacteria were 0.7-1.2 and 0.5-1.0, respectively. The characterization of microbial communities in drinking water can be performed using biochemical and/or molecular methods. In this study, biochemical tests were used, showing that pseudomonad and pseudomonad-like bacteria, as in other studies, were the most predominant micro-organisms (e.g. Pseudomonas fluorescens, Brevundimonas vescularis). The ratio Gram-positive to Gram-negative organisms was 1 to 3. No drastic differences were observed between the non-treated and disinfected pipes. Based on the bacteriological data presented in these experiments, chlorine dioxide represents an alternative to chlorine for certain distribution systems. 相似文献
94.
Dykstra DD Wieting JM McGuire J Kowalkowski T 《Archives of physical medicine and rehabilitation》2002,83(11):1638-1640
OBJECTIVES: To determine the residual botulinum toxin remaining in vials after using 3 different extraction methods and to analyze the different techniques for measuring extraction efficacy. DESIGN: Multicentered comparative study. SETTING: Three academic movement disorder clinics. PARTICIPANTS: Thirty physicians were randomly surveyed for their botulinum toxin extraction methods. Three physicians evaluated the most common methods. INTERVENTIONS: Not applicable. MAIN OUTCOME MEASURE: Amount of toxin left in vials after each extraction method. RESULTS: Toxin was least successfully extracted by using the vial inversion method. More toxin was extracted by using the 2-in needle method. The top removal method produced the least waste of toxin but is considered unsafe. CONCLUSIONS: The best and safest method for consistently extracting the most botulinum toxin from its vial was to use a long 21-gauge 2-in needle attached to a 3-mL syringe. 相似文献
95.
A treatment planning inter-comparison of proton and intensity modulated photon radiotherapy. 总被引:2,自引:0,他引:2
A J Lomax T Bortfeld G Goitein J Debus C Dykstra P A Tercier P A Coucke R O Mirimanoff 《Radiotherapy and oncology》1999,51(3):257-271
PURPOSE: A comparative treatment planning study has been undertaken between standard photon delivery techniques,b intensity modulated photon methods and spot scanned protons in order to investigate the merits and limitations of each of these treatment approaches. METHODS: Plans for each modality were performed using CT scans and planning information for nine patients with varying indications and lesion sites and the results have been analysed using a variety of dose and volume based parameters. RESULTS: Over all cases, it is predicted that the use of protons could lead to a reduction of the total integral dose by a factor three compared to standard photon techniques and a factor two compared to IM photon plans. In addition, in all but one Organ at Risk (OAR) for one case, protons are predicted to reduce both mean OAR dose and the irradiated volume at the 50% mean target dose level compared to both photon methods. However, when considering the volume of an OAR irradiated to 70% or more of the target dose, little difference could be shown between proton and intensity modulated photon plans. On comparing the magnitude of dose hot spots in OARs resulting from the proton and IM photon plans, more variation was observed, and the ranking of the plans was then found to be case and OAR dependent. CONCLUSIONS: The use of protons has been found to reduce the medium to low dose load (below about 70% of the target dose) to OARs and all non-target tissues compared to both standard and inversely planned photons, but that the use of intensity modulated photons can result in similar levels of high dose conformation to that afforded by protons. However, the introduction of inverse planning methods for protons is necessary before general conclusions on the relative efficacy of photons and protons can be drawn. 相似文献
96.
Linda Kirschen Mcloon Jon H. Falkenberg Dennis Dykstra Paul A. Iaizzo 《Muscle & nerve》1998,21(11):1457-1464
The sternocleidomastoid muscle (SCM) is one of the major muscles involved in producing abnormal head position in cervical dystonia patients. This study tested whether doxorubicin chemomyectomy, direct injection of doxorubicin into the SCM to permanently remove muscle fibers, has the potential to be a nonsurgical, permanent treatment for cervical dystonia. The right SCM of rabbits was injected with either 1 or 2 mg doxorubicin. Animals were sacrificed 1–2 months postinjection. The SCM was prepared for histological examination of muscle fiber loss and fiber type composition. In all cases, direct injection of doxorubicin resulted in significant decreases in total muscle cross-sectional areas ranging from 75% up to 98%. Individual myofiber cross-sectional areas were smaller than normal after 2 mg doxorubicin treatment, but similar to normal fiber size after 1 mg doxorubicin. There were increased numbers of myofibers that expressed slow and neonatal myosin heavy chain isoforms in these remaining muscle fibers compared to the untreated SCM on the contralateral side. Developmental myosin heavy chain (MHC) was also present in 53% of the remaining myofibers of the treated muscles. The fiber type composition of muscles contralateral to the doxorubicin injections was compared to the fiber type composition of SCM from normal, untreated controls; no difference was seen in the proportions of fast, slow, and neonatal MHC fiber types in these SCM muscles. In summary, the direct injection of doxorubicin into the SCM resulted in significant muscle loss. This supports the use of doxorubicin chemomyectomy as a potential permanent, nonsurgical treatment for cervical dystonia. © 1998 John Wiley & Sons, Inc. Muscle Nerve 21: 1457–1464, 1998 相似文献
97.
This paper examines cognitive antecedents of non-smoking among adolescents who reported smoking less than 1–2 times a week, and reported non-smoking intentions and willingness, in the framework of the Prototype/Willingness model. Two waves of data were obtained from a nation-wide sample of 760 Norwegian adolescents who responded to a school-based survey on smoking. Structural equation modelling was used to evaluate the predictive power of the social reaction pathway (prototype and willingness) of the P/W model, and in addition, the constructs from the Theory of Reasoned Action (subjective norm, attitude and intention). Results demonstrated the unique importance of the social reaction path when examining smoking behaviour among non-smoking adolescents. Implications of the findings and possible applications are discussed. 相似文献
98.
This study investigates support provided to older parents by non-resident children and compares older adults in various living
arrangements, based on a typology of current partner status, marital history and gender. Data come from the Dutch 1992 survey
on older adults living arrangements and social networks (NESTOR-LSN). The 4494 respondents constituted a random sample of
men and women born in the years 1903 to 1937. The findings, based on those with ADL- and/or IADL-limitations and with living
children (N=2182), point out that ever-divorced men, regardless of whether they have repartnered, receive only marginal help from their children.
Among those without new partners, 8 percent of the ever-divorced men and 22 percent of the ever-divorced women cite children
as sources of help, while this is so for 45 percent of the ever-widowed men and 53 percent of the ever-widowed women. Multivariate
analyses revealed that health, educational level, number of children and travel distance are significant predictors of support
from children, in addition to the significant and important contribution of marital history, partner status and gender.
is currently a Permanent Fellow of the Netherlands Institute for Advanced Study in the Humanities and Social Sciences (NIAS)
of the Royal Netherlands Academy of Arts and Sciences. In the period 1987 to 2000 she was director of the Netherlands Interdisciplinary
Demographic Institute (NIDI). Her main interest is the demographic and social aspects of ageing of the population.
Pearl A. Dykstra is a senior researcher at the Netherlands Interdisciplinary Demographic Institute (NIDI) and Professor of Family Demography
at Utrecht University. Her publications focus on late life families, and ageing and the life course. At present she is the
coordinator of the Netherlands Kinship Panel Study (NKPS), a longitudinal study of 10,000 individuals and their families funded
by the Netherlands Organization for Scientific Research (NWO). 相似文献
99.
Butorphanol, levallorphan, nalbuphine and nalorphine as antagonists in the squirrel monkey 总被引:2,自引:0,他引:2
L A Dykstra 《The Journal of pharmacology and experimental therapeutics》1990,254(1):245-252
The effects of several mixed-action opioid agonist/antagonists were examined alone and in combination with the mu-opioid agonist l-methadone and the kappa-opioid agonist, trans-3,4-dichloro-N-methyl-N[2-(1-pyrrolidinyl)cyclohexyl]benzeneace tam ide (U50,488). Effects were examined in squirrel monkeys responding under a schedule of shock titration. Under this procedure shock was scheduled to increase once every 15 sec from 0.01 to 3.7 mA in 30 steps. Five responses on a lever during the 15-sec shock period terminated the shock for 15 sec, after which the shock resumed at the next lower intensity. The intensity below which the monkeys maintained the shock 50% of the time (median shock level) was determined. l-Methadone and U50,488 produced dose-dependent increases in median shock level. Nalbuphine, butorphanol and levallorphan also increased median shock level, but these increases were much smaller than those observed with l-methadone or U50,488. Nalorphine and naltrexone did not increase median shock level. Butorphanol, levallorphan, nalbupine, nalorphine and naltrexone all produced parallel, rightward shifts in both the l-methadone and U50,488 dose-effect curves. The apparent pA2 values obtained for naltrexone in combination with l-methadone (7.7) were at least one log unit larger than those obtained for naltrexone in combination with U50,488 (6.5). Similar differences were revealed for nalbuphine in combination with l-methadone (6.1) and U50,488 (5.2) as well as for nalorphine in combination with l-methadone (6.0) and U50,488 (5.5).(ABSTRACT TRUNCATED AT 250 WORDS) 相似文献
100.
Richard M Allen Arthur L Granger Linda A Dykstra 《The Journal of pharmacology and experimental therapeutics》2002,300(2):435-441
Dextromethorphan (DXM) is a noncompetitive N-methyl-D-aspartate (NMDA) receptor antagonist shown to prevent the development of tolerance to the antinociceptive effects of morphine in rodents. DXM also potentiates the antinociceptive effects of the mu-opioid receptor agonist morphine under some conditions; however, the effect of DXM in combination with opioids other than morphine has not been well characterized. This study determined the antinociceptive effects of DXM administered alone or in combination with morphine or the delta-opioid receptor (DOR) agonist SNC80 using a squirrel monkey titration procedure. In this procedure, shock (delivered to the tail) increases in intensity every 15 s (0.01-2.0 mA) in 30 increments. Five lever presses during any given 15-s shock period produces a 15-s shock-free period after which shock resumes at the next lower intensity. This assay provides a measure of antinociception that is separable from motor effects [response rate (RR)]. Morphine (0.3-3.0 mg/kg i.m.) and SNC80 (1.0-10 mg/kg i.m.), but not DXM (1.0-10 mg/kg i.m.) dose- and time-dependently increased the intensity below which monkeys (n = 4) maintained shock 50% of the time [median shock level (MSL)]. Doses of morphine and SNC80 that alone did not increase MSL were potentiated by DXM. Importantly, these combinations did not significantly alter RR. These data support previous findings with other NMDA receptor antagonists and morphine using this procedure and also extend those findings to a DOR agonist. 相似文献