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291.
292.
KA Peace SM Orme JP Sebastian AR Thompson S Barnes A Ellis PE Belchetz 《Canadian Metallurgical Quarterly》1997,46(4):445-450
The effect of 50 days of streptozotocine-induced diabetes mellitus (blood glucose 20 mmol/l) on contraction and relaxation of isolated renal and intrarenal arteries in rats were examined. Strong and similar contractions were induced by potassium (60 mM), 5-hydroxytryptamine (5-HT) and endothelin-1 (ET-1) in renal and intrarenal arteries in diabetic and control rats. The vasodilatory reactivity, after precontraction with 5-HT, of neuropeptide Y (NPY) was similar to that of acetylcholine (ACh), calcitonin gene-related peptide (CGRP) and vasoactive intestinal polypeptide (VIP) and was similar in diabetic and control rats. The relaxing effect of NPY was decreased (40%) only in the diabetic group by blockade of nitric oxide synthase with NG-nitro-L-arginine methyl ester (10(-4) M) and by blockade (50%) of NPY with alpha-trinositol (10(-6) M). In conclusion, the present study showed that diabetes mellitus in the rat is associated with normal vasoconstrictive and vasodilatory capacities. However, the vasodilatory response to NPY was largely eliminated by blockade of nitric oxide synthesis only in the diabetic animals. This indicates that the vasodilatory effect of NPY in diabetes mellitus may be dependent on nitric oxide synthesis. 相似文献
293.
The induction of Fas ligand (FasL) mRNA expression and FasL-mediated cytotoxicity in CD8+ CTL is a rapid and transient response to activation via the TCR. This response can also be initiated by pharmacologic activation of two major TCR signaling pathways using phorbol ester (PMA) and calcium ionophore (ionomycin). In these experiments using CD8+ alloreactive cell lines, we demonstrate that induction of FasL mRNA can occur in response to either PMA or ionomycin independently. However, only the ionomycin pathway is sensitive to inhibition by cyclosporine A. Both pathways are blocked by genistein, a general protein tyrosine kinase inhibitor. The magnitude of induction of FasL mRNA is not proportional to the manifested FasL-dependent cytotoxicity. We also found a calcium requirement for cytotoxicity that is unrelated to FasL mRNA induction. In addition to the positive effects of constitutive and induced calcium levels on FasL-mediated cytotoxicity, calcium may play a role in the rapid down-regulation of the response. We also present data suggesting that CD2 and LFA-1 contribute to FasL-mediated cytotoxicity. Together these results suggest pathways by which partial TCR activation could, among the many activation-induced functions of a T cell, selectively lead to the induction of FasL-mediated cytotoxicity that can be regulated by lineage/ activation-dependent accessory molecules on the target. 相似文献
294.
In contrast to the many neural studies into the mechanisms of sleep onset and maintenance, few studies have focused specifically on awakening from sleep. However, the abrupt electrographic changes and large brief cardio-respiratory activation at awakening suggest that a distinct, transiently aroused, awake state may exist compared to later wakefulness. To test this hypothesis we utilized the acoustic startle reflex, a standard un-conditioned reflex elicited by a sudden loud noise. This reflex is modulated under specific conditions, one being a diminution of startle when a quieter pre-stimulus is presented immediately before the loud stimulus. This pre-pulse inhibition (PPI) is used as a measure of sensorimotor gating, with smaller PPI indicating less filtering of sensory inputs and increased responsiveness to external stimuli. Eight rats with electrodes for recording sleep-wake state were studied. An accelerometer measured startle responses. The startle reflex was elicited by 115 dB, 40 ms tones. PPI was produced by 74 dB, 20 ms tones preceding the 115 dB tone by 100 ms. Responses within 100 ms were measured. Stimuli were applied either 3-10 s after spontaneous awakenings, or in established wakefulness (> 30 s). Responses to the startle stimuli alone were similar in the different awake states (P = 0.821). However, PPI was smaller at awakening from non-REM sleep compared to established wakefulness (45.4 +/- 7.5% vs. 74.3 +/- 6.1%, P = 0.0002). PPI after awakening from REM sleep (52.8 +/- 17.9%) was not significantly different than established wakefulness (P = 0.297). Reduced PPI of the startle reflex at awakening from non-REM sleep supports the hypothesis that wakefulness immediately after spontaneous sleep episodes is neurophysiologically distinct from later wakefulness and associated with reduced gating of motor responses to sensory inputs. Spontaneous activation of this distinct, transiently aroused, state upon awakening may serve a protective function, preparing an animal to respond immediately to potentially threatening stimuli. 相似文献
295.
We have explored a role for the adenovirus (Ad5) E1b58kDa/p53 protein complex in adenovirus replication. This was done by using virus mutants containing different defects in the E1b58kDa gene and cell lines that express either a wild-type p53 protein or a mutant p53 protein. We find that infection of wild-type p53-containing cells with wild-type Ad5 causes a shutoff of p53 and alpha-actin protein synthesis by distinct mechanisms, but neither occurs in mutant p53 cells. Our data also indicate that the shutoff is dependent on formation of the p53/E1b complex and may also involve another virus protein, E4ORF6. Following from these observations we asked whether failure to form the complex resulted in impaired adenovirus replication. Our experiments showed that neither wild-type Ad5 nor the E1b mutant dl338 could replicate in cells expressing a mutant p53 protein, but that wild-type adenovirus replicated well in wild-type p53-expressing cells. Collectively, our data suggest that the interaction between p53 and the E1b58kDa protein is necessary for efficient adenovirus replication. This is the first time such a direct link between the complex and virus replication has been demonstrated. These data raise serious questions about the usefulness of E1b-defective viruses in tumor therapy. 相似文献
296.
Hypocomplementemic urticarial vasculitis (HUV) is often misdiagnosed. The response to drug therapy may be unsatisfactory, and immunosuppressive therapy may be associated with significant side effects. A 35-year-old patient whose condition was resistant to cyclophosphamide, corticosteroids, pentoxyphylline, cyproheptadine, sulindac, and colchicine was maintained in remission with dapsone, which may be the drug of choice for HUV. Emphysema has been reported to complicate HUV, but this is the first account of vasculitis-related emphysema with no confounding history of tobacco smoke exposure. The relationship of proteolytic injury to the pulmonary and other manifestations is considered, as is the possible role for dapsone in reducing it. 相似文献
297.
M Castro Pazos AR Juncal Fondevila S Aldecoa Landesa JC Calvo Fernández 《Canadian Metallurgical Quarterly》1997,20(5):267-268
In order to investigate the function of epidermal growth factor (EGF), the following experiments were performed. Thirty white rats were chosen and divided into 3 groups. In the back of each rat, two 2 cm x 2 cm wounds were made bilaterally, the skin and subcutaneous tissue was removed. EGF were used in one of the two wounds randomly, while those without EGF usage in control. After 1, 2 and 3 weeks, the rats were sacrificed. The area of the wounds was measured, and the healing time of each wound was recorded. The results showed that the healing time of EGF group was 14.6 days while that of control group was 18.5 days (P < 0.01). Furthermore, the DNA, protein and hydroxyproline contents of EGF group were higher than those of the control group (P < 0.01). It was suggested the EGF could accelerate wound healing and shorten the healing time. 相似文献
298.
Affinity matured murine monoclonal antibody producing cell lines can now be rapidly generated using a novel repetitive, multiple site immunization strategy designated RIMMS. RIMMS capitalizes on rapid hypermutation and affinity maturation events which occur in B cell populations localized within secondary lymphatic tissue early in response to antigenic challenges. A murine myeloma cell line, P3XBcl-2-13, stably transfected with Bcl-2, enhances the outgrowth of hybridomas following somatic fusion with immune lymphocytes isolated from pooled peripheral lymph nodes (PLN) 8-14 days after the initial immunization. Immunizations somatic fusion, screening and isolation of affinity matured IgG secreting monoclonal antibody cell lines occur within a one month time period. By using RIMMS, we have been able to expedite the isolation of affinity matured monoclonal antibodies to numerous antigens, including a drug hapten. 相似文献
299.
300.
PURPOSE: To present an ultrasonographic finding that simulated an intraocular foreign body after repair of a ruptured globe. METHOD: Case report. An ultrasonogram of a post-trauma eye was correlated with a computed tomographic scan. RESULTS: B-scan ultrasonography was performed on an eye after repair of a corneoscleral laceration. The ultrasonogram showed a highly reflective echo source suggestive of a foreign body; however, an orbital computed tomographic scan demonstrated that the lesion was intraorbital air. CONCLUSION: Although a highly reflective echo source in the presence of a ruptured globe may suggest a foreign body, the presence of orbital air should also be considered when interpreting ultrasonograms used in the preoperative and postoperative management of globe trauma. 相似文献