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排序方式: 共有1162条查询结果,搜索用时 609 毫秒
171.
LP Morssink BT de Wolf LH Kornman JR Beekhuis TP van der Hall A Mantingh 《Canadian Metallurgical Quarterly》1996,103(8):779-783
To disclose the cytoprotective mechanism of 1,6-dihydro-2[2-(2-methyoxypropoxy)anilino]-6-oxo-5-pyrimidinecarb oxylic acid (CAS 98772-05-5, MAR-99), the effect of this compound on the microvascular injury in gastric mucosa induced by 99.5% ethanol in rats was studied. In this experiment, it was found that the elevation of vascular permeability observed at the early state of ethanol-induced gastric mucosal injury was closely correlated with the combined action of histamine and slow reacting substance (leukotriene C4, LTC4). MAR-99 (0.3-10 mg/kg p.o.) prevented dose-dependently the increase in vascular permeability. Furthermore, MAR-99 (10 mg/kg p.o.) improved the decrease in the number of histamine containing cells and histamine content, and prevented the production of LTC4. These results suggest that MAR-99 exerts its anti-microvascular injury effect by regulating the release of histamine and the production of LTC4 in glandular stomach against ethanol, and this effect may contribute to the anti-lesion effect of this compound. 相似文献
172.
AN Viktorov ND Novikova EA Deshevaia MP Bragina AV Shnyreva TP Sizova IuT D'iakov 《Canadian Metallurgical Quarterly》1998,32(5):57-62
Results of many years of the survey of highly specific evolution of quantitative and species composition of microflora of the MIR environment are reviewed. Analysis of the data enabled listing of microorganisms-declinous fungi with the ability of residential colonization of structural materials of the interior and equipment of habitable modules of the space station. Results of the studies of variability and level of similarity/affinity on the basis of DNA, polymorphism of strains isolated in space flight, convincingly confirmed this characteristic in the Penicillium chrysogenum cultures. In view of the common origin determined from the signs of genetic alliance, the P. chrysogenum strains isolated on MIR in 1995 can be considered descendants of the cultures found at the beginning of the MIR operation. This ecological expansion of P. chrysogenum in the space station environment gains in prominence due to the fact that representative of this particular species known for its active biodestructive nature were, as a rule, detected in the areas where structural materials of the SALYUT and MIR space stations incurred biological degradation. 相似文献
173.
174.
The vestibulo-ocular reflex (VOR) of 125 healthy subjects was examined over the frequency range of 0.5-5 Hz with the head autorotation test (HART). During the HART the subjects fixated at a steady target while moving their heads horizontally from side to side with increasing frequencies according to auditory signals. The gain was determined as the ratio between the amplitude of the eye and head movements in five frequency bands between 0.5 and 5 Hz. The phase difference between the eye and head movements was determined in both degrees and milliseconds. The ability to reach high-frequency bands was evaluated. The mean gain was close to unity up 5 Hz, when it decreased to 0.91. The mean phase difference showed a lead of approximately 5 degrees at frequencies below 2 Hz, and at frequencies above 2 Hz there was no phase difference within the resolution of the test. The frequency band of 5 Hz was reached by 78% of the subjects, and that of 4 Hz was reached by 94% of the subjects. In summary, the HART is a new approach with which to study VOR function and determine accurately the VOR for healthy subjects. The normal upper frequency limit is 4 Hz in the HART. 相似文献
175.
Enhancement of DNA vaccine immunogenicity is a current topic of high priority in the field of applied immunology, especially as a means of controlling HIV infection. The adjuvant effect of Ubenimex (UBX), an anti-cancer immunomodulator, on a DNA AIDS vaccine which we developed was examined in a murine model. UBX was formulated into a preparation containing DNA plasmids encoding env and rev genes of HIV-1 strain III(B), and was inoculated intramuscularly into BALB/c mice. The sera obtained with this mixture had 2(3)-2(5) times higher specific IgG titres than those obtained without the use of the adjuvant. UBX also elicited both a stronger HIV-1-specific DTH reaction, as measured by the footpad swelling test, and stronger cytotoxic T lymphocyte activity, as assayed by the 51Cr-release method, compared with responses using DNA alone. The cytokine secretion profile of restimulated immune lymphoid cells showed that UBX raised IL-2 and interferon-gamma levels and decreased IL-4 production. HIV-1-specific immunoglobulin subtype analysis demonstrated that UBX stimulated IgG2a production but suppressed synthesis of IgG1 and IgE. These results indicate that activation of the T-helper type 1 subset was induced by UBX, suggesting a mechanism of immunomodulation mediated by this agent. We conclude that UBX acts as an immunologic adjuvant for DNA vaccination against HIV-1. UBX may be a suitable adjuvant for clinical use because of its lack of antigenicity and low toxicity. 相似文献
176.
The effects of acute and repeated nicotine administration on the stress response of rat mesoprefrontal dopaminergic pathways were examined. Rats were given daily injections of nicotine (0.15 or 0.60 mg/kg, s.c., freebase) or saline for 4 days, then challenged with either nicotine or saline. A regimen of inescapable electrical footshocks or no footshocks was then administered. Thirty minutes after final injection, rats were sacrificed, brains removed and dopamine (DA) and its metabolite dihydroxy-O-phenylacetic acid (DOPAC) were extracted from medial prefrontal cortex (mPFC), nucleus accumbens septi (NAS) and dorsolateral striatum and quantified by high performance liquid chromatography with electrochemical detection. Acute administration of low dose nicotine (0.15 mg/kg) produced an increase in DA utilization (increased DOPAC/DA ratio) in mPFC and NAS, but not striatum. High dose nicotine (0.60 mg/kg) produced activation in NAS, but not mPFC or striatum. Repeated low dose nicotine pre-treatment produced tolerance to the effects of nicotine challenge in the mPFC, and reduced its effects in NAS. Footshock stress preferentially increased DA utilization in mPFC and associated footshock stress-induced immobility responses, and these were reduced by low, but not high, dose repeated nicotine pre-treatment. Further, a single dose of the nicotinic acetylcholine receptor (nAChR) antagonist mecamylamine (MCA) 30 min prior to nicotine challenge dose-dependently blocked the reduction of mesoprefrontal DA stress responsivity and immobility responses produced by repeated nicotine pre-treatment. These results indicate that: (1) there are dose-dependent differential effects of acute and repeated nicotine pre-exposure on regional DA utilization; (2) low, but not high, dose repeated nicotine reduces both the mesoprefrontal DA and behavioral effects of acute footshock stress; and (3) these effects of repeated nicotine may depend on mecamylamine-sensitive nAChR stimulation. These results may have relevance to acute stress and nicotine dependence, particularly in schizophrenic disorders, which have high prevalence rates of co-morbid nicotine dependence, stress-induced symptom exacerbation and prefrontal cortical dysfunction. 相似文献
177.
WF Gee HL Holtgrewe ML Blute BJ Miles MJ Naslund RE Nellans MP O'Leary R Thomas MR Painter JJ Meyer TJ Rohner TP Cooper R Blizzard RB Fenninger L Emmons 《Canadian Metallurgical Quarterly》1998,160(5):1804-1807
PURPOSE: The American Urological Association first commissioned the Gallup Organization to conduct a study to assess urologist practice patterns in 1992. We present the results of the 1997 survey, the sixth consecutive Gallup survey performed for the Association. MATERIALS AND METHODS: A random sample of 502 American urologists who had completed urological residency and practiced at least 20 hours weekly in 1996 was interviewed by telephone in February and March 1997. RESULTS: Emerging trends showed significant changes since 1994 in how urologists diagnosed and treated prostate cancer. The survey revealed a significant change in the tests routinely ordered to stage newly diagnosed prostate cancer and for diagnostic evaluation of patients with benign prostatic hyperplasia. CONCLUSIONS: Urologists are becoming more cost conscious and effective in ordering pretreatment testing. Urologists are becoming more oriented toward medical treatment for the management of benign prostatic hyperplasia, and less laser surgery is being performed. 相似文献
178.
179.
TP Ma 《Canadian Metallurgical Quarterly》1996,7(15-17):2713-2716
The zona incerta contains GABAergic neurons projecting directly on to collicular efferent neurons. This study examined the physiological characteristics of incertal neurons and their relationship to saccades. Cells in the zona incerta have moderate rates of activity and pause during saccades. These pauses begin prior to the start of saccades and activity resumes after the end of saccades in all directions and for all amplitudes. This perisaccadic pause is positively correlated with the duration of the saccade such that the longer the saccade is, the longer a pause is observed. These physiological data, in conjunction with anatomical observations, suggest that the zona incerta might normally function by inhibiting the superior colliculus and then by disinhibiting the superior colliculus for saccades. 相似文献
180.
Leukocyte transfusion-associated granulocyte responses in a patient with X-linked hyper-IgM syndrome
TP Atkinson CA Smith YM Hsu E Garber L Su TH Howard JT Prchal MP Everson MD Cooper 《Canadian Metallurgical Quarterly》1998,18(6):430-439
X-linked hyper-IgM syndrome (XHIM) is a severe congenital immunodeficiency caused by mutations in CD154 (CD40 ligand, gp39), the T cell ligand for CD40 on B cells. Chronic or cyclic neutropenia is a frequent complicating feature that heightens susceptibility to severe infections. We describe a patient with a variant of XHIM who produced elevated levels of serum IgA as well as IgM and suffered from chronic severe neutropenia. Eight of ten leukocyte transfusions with cells from a maternal aunt, performed because of mucosal infections, resulted in similar episodes of endogenous granulocyte production. Transfection studies with the mutant CD154 protein indicate that the protein is expressed at the cell surface and forms an aberrant trimer that does not interact with CD40. The data suggest that allogeneic cells from the patient's aunt, probably activated T cells bearing functional CD154, may interact with CD40+ recipient cells to produce maturation of myeloid precursors in the bone marrow. 相似文献