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41.
Human prostate cancer (PC) cell lines possess epidermal growth factor (EGF) receptors and secrete EGF-related polypeptides. We used an EGF receptor-blocking antibody (anti-EGF.R) to demonstrate a functional autocrine loop, as well as the interaction between this and the effects of linoleic acid (LA), an omega-6 fatty acid, on PC cell growth. The anti-EGF.R competed effectively with [125I]EGF for receptors on DU145 PC cells, and on a high-passage DU145 variant (DU145M); when added to the culture medium, it suppressed both DU145 and DU145M cell growth in a dose-dependent manner. LA, a precursor for eicosanoid synthesis, had little effect on DU145 cell growth rate but stimulated DU145M growth in a concentration-related manner over a range of 0.25-2.0 micrograms/ml. anti-EGF.R (10(-9) M) caused suppression of LA-stimulated growth of DU145M cells in serum-free medium, which was prevented by the addition of 2 nM EGF. We conclude that an EGF.R-mediated autocrine loop is involved in PC cell growth regulation and that at least one site of action may be the synthesis of eicosanoids from their LA precursor. 相似文献
42.
急性颅脑损伤患者脑脊液中兴奋性和抑制性氨基酸含量改变及其临床意义 总被引:1,自引:0,他引:1
采用氨基酸自动分析仪检测了18例急性颅脑损伤患者脑脊液中谷氨酸、天门冬氨酸、牛磺酸、甘氨酸、丙氨酸、γ-氨基丁酸、脯氨酸含量的动态变化。结果发现,伤情越重、预后越差的患者,脑脊液中牛磺酸、γ-氨基丁酸、丙氨酸含量伤后早期升高越明显,恢复至正常的时间也越长;其中2例早期死于急性弥漫性脑肿胀、脑水肿的患者,伤后当天脑脊液中牛磺酸含量分别为92.6和51.5μmol/L,是对照值的9.6倍和5.4倍,γ-氨基丁酸含量分别为119.8和246.2μmol/L,是对照值的2.7倍和5.5倍。表明伤后脑脊液中牛磺酸、γ-氨基丁酸和丙氨酸含量的动态变化可初步反映颅脑损伤的严重程度及颅脑损伤患者的脑功能恢复状况,并可能与急性脑水肿、脑肿胀的病理生理过程有关。 相似文献
43.
M. AXELSEN P. LO¨NNROTH R. ARVIDSSON LENNER & U. SMITH 《European journal of clinical investigation》1997,27(2):157-163
The aim of the present study was to examine the effects of a large dose of slow-release carbohydrates (CHOs) at bedtime on the nocturnal glucose, insulin and free fatty acid (FFA) levels, and to assess the putative effects on morning fasting and post-prandial glucose levels in patients with moderately controlled non-insulin-dependent diabetes mellitus (NIDDM). Unheated cornstarch (106 g of CHO) or a mixed equicaloric meal (58 g of CHO) was given at 22.00 hours to 10 NIDDM patients. For comparison, the patients were also given a smaller mixed meal at 22.00 hours on a third occasion (17 g of CHO). Compared with the mixed meals, cornstarch led to a slightly elevated early-morning plasma insulin level and a suppression of the nocturnal FFA level ( P < 0.05), as well as to a reduced incremental glucose level (IAUC) after breakfast the next morning by approximately 30% ( P < 0.05). There was a significant and linear relationship between the nocturnal FFA level and the glucose IAUC after breakfast ( r = 0.44, P < 0.02), indicating that the effect may have been mediated by the suppressive effect of cornstarch on nocturnal lipolysis. In summary, bedtime intake of unheated cornstarch in NIDDM subjects is associated with a suppression of the nocturnal FFA levels and a reduced glucose IAUC after breakfast. As the treatment did not improve overall glucose control, studies of the effects of an individually titrated amount of cornstarch are proposed to further explore the putative favourable effects of bedtime cornstarch in the treatment of NIDDM. 相似文献
44.
兴奋性氨基酸类神经毒剂与粉防己碱(tetrandrine,Tet)共同作用于原代培养胎鼠大脑皮层神经元24小时,发现107,106mol·L1Tet明显降低50μmol·L1谷氨酸(glutamate,Glu),300μmol·L1βNmethylaminoLalanine(BMAA,NMDA受体激动剂)和20μmol·L1βNoxalylaminoLalanine(BOAA,nonNMDA受体激动剂)导致的培养液乳酸脱氢酶(lactatedehydrogenase,LDH)活性的增高;细胞形态损害减轻,细胞数量增加。对20μmol·L1NMDA介导的神经元损伤改变无影响。提示Tet对某些Glu类神经毒剂引起的胎鼠大脑皮层神经元损伤有一定保护作用,其机制可能是抑制细胞膜上的Na+通道开放,阻止膜去极化而影响电压依赖性Ca2+通道启动。对NMDA受体可能亦有一定作用。 相似文献
45.
Thoracic epidural analgesia in aortocoronary bypass surgery II: effects on the endocrine metabolic response 总被引:3,自引:0,他引:3
R. STENSETH L. BJELLA E. M. BERG O. CHRISTENSEN O. W. LEVANG S. E. GISVOLD 《Acta anaesthesiologica Scandinavica》1994,38(8):834-839
Thoracic epidural analgesia (TEA) may offer haemodynamic benefits for patients with coronary heart disease going through major surgery. This may – in part – be secondary to an effect on the endocrine and metabolic response to surgery. We therefore investigated the effect of TEA on the endocrine metabolic response to aortocoronary bypass surgery (ACBS).
Thirty male patients (age < 65 years, ejection fraction > 0.5) were randomized into 3 groups; the HF group receiving a high dose fentanyl (55 μg–kg-1 ) anaesthesia, the HF + TEA group with the same fentanyl dose + TEA with 10 ml bupivacain 5 mg ml-1 , followed by 4 ml every hour, and the LF + TEA group receiving fentanyl 15 μg kg-1 + TEA. Adrenalin, noradrenalin, systemic vascular resistance (SVR), glucose, Cortisol, lactate and free fatty acids were followed during the operation and for 20 h postoperatively.
A significant increase in adrenalin, noradrenalin and SVR was found in the HF group whereas this increase was blocked in both epidural groups. An increase in glucose and Cortisol was noticed in all groups, but the increase was delayed in the epidural groups.
Our results suggest that a more effective blockade of the stress response during ACBS is obtained when TEA is added to general anaesthesia than with high dose fentanyl anaesthesia alone. 相似文献
Thirty male patients (age < 65 years, ejection fraction > 0.5) were randomized into 3 groups; the HF group receiving a high dose fentanyl (55 μg–kg
A significant increase in adrenalin, noradrenalin and SVR was found in the HF group whereas this increase was blocked in both epidural groups. An increase in glucose and Cortisol was noticed in all groups, but the increase was delayed in the epidural groups.
Our results suggest that a more effective blockade of the stress response during ACBS is obtained when TEA is added to general anaesthesia than with high dose fentanyl anaesthesia alone. 相似文献
46.
In the cortex only a few of the available NMDA receptors must be activated to evoke maximal release of adenosine. In fact, maximal adenosine release occurs at 30 μM NMDA, a concentration at which noradrenaline release is only 20% maximal. NMDA-evoked noradrenaline release appears to require the generation of propagated action potentials, while adenosine release does not. Noncompetitive block of NMDA-evoked release of adenosine, but not noradrenaline, can be overcome by increasing NMDA concentrations. The above findings are consistent with the possibility that there are spare receptors for NMDA-evoked adenosine release, but not for nor-adrenaline release. These spare receptors are not due to elevated levels of glycine in the vicinity of those NMDA receptors mediating adenosine release. Functionally, it appears that low level NMDA receptor activation provides a purinergic inhibitory threshold against higher level NMDA receptor mediated processes. This could provide inhibitory tone and selectivity for critical functions, such as learning, memory, and synaptic plasticity in the cortex. © 1993 Wiley-Liss, Inc. 相似文献
47.
反相高压液相色谱法测定血清中部分氨基酸 总被引:8,自引:0,他引:8
目的:建立测定血清中精氨酸含量的方法。方法:反相高压液相色谱法。HypersilBDS柱,邻苯二甲醛柱前衍生化、萤光检测法检测。结果:精氨酸线性范围为383μmol/L~4789μmol/L,8种氨基酸的最低检测限为2μmol/L,日内变异系数为275%~1193%,日间变异系数为705%~1239%,5种氨基酸的回收率为9633%~10078%。正常人血清精氨酸水平为9277±1790μmol/L,糖尿病患者血清精氨酸水平则为7861±3303μmol/L(P>005)。结论:本方法简单易行,方法学实验结果满意,适用于临床测定相关氨基酸的需要 相似文献
48.
LAURENT MICLO EMMANUEL PERRIN ALAIN DRIOU MICHEL MELLET GUY LINDEN 《Chemical biology & drug design》1995,46(2):186-192
A method for the simultaneous determination of the ratios of the three aromatic amino-acid residues in peptides was set up in acidic conditions. Binary and ternary mixtures of these amino acids were prepared, and first- and second-derivative spectra then calculated from their 0.1 nm resolution spectra between 240 and 320 nm. Certain spectral bands were chosen to differentiate tyrosine from tryptophan on the first-derivative spectra, and phenylalanine from tyrosine and tryptophan on the second-derivative spectra. Variation of the amplitude of the chosen bands was shown to be a linear function of the ratio of the aromatic amino acids in the mixture. This technique was validated with peptides whose sequence was known. The difference between theoretical and experimentally determined ratios was lower than 10%. Since the results are obtained as ratios, neither the concentration nor the nature of the peptide has to be known. The feasibility of application using a photodiode array detector with high resolution in reversed-phase high-performance liquid chromatography is discussed. © Munksgaard 1995. 相似文献
49.
James T. Winslow Thomas R. Insel 《Progress in neuro-psychopharmacology & biological psychiatry》1991,15(6):745-757
1. Rat pups emit ultrasonic calls during brief episodes of social separation. These calls have been variously described as “distress” calls and may be related to the separation cries expressed by the young of many mammalian species.
2. Ultrasonic call of rat pups are modulated by environmental stimuli such as ambient temperature, olfactory and tactile stimuli associated with the nest.
3. Calls are also sensitive to a variety of purported anxiolytic and anxiogenic drugs, including the benzodiazepines, serotonin agonists, and ligands at the NMDA-glycine receptor complex.
4. In addition to providing a simple test for the anxiolytic properties of drugs, this model may also provide new insights about the development and neurobiology of anxiety. 相似文献
50.
The synthesis is of Tyr(P)-containing peptides by the use of Fmoc-Tyr(PO3Me2)-OH in Fmoc/solid phase synthesis is complicated since, firstly, piperidine causes cleavage of the methyl group from the -Tyr(PO3 Me2)-residue during peptide synthesis and, secondly, harsh conditions are needed for its final cleavage. A very simple method for the synthesis of Tyr(P)-containing peptides using t-butyl phosphate protection is described. The protected phosphotyrosine derivative, Fmoc-Tyr(PO3tBu2)-OH was prepared in high yield from Fmoc-Tyr-OH by a one-step procedure which employed di-t-butyl N,N-diethyl-phosphoramidite as the phosphorylation reagent. The use of this derivative in Fmoc/solid phase peptide synthesis is demonstrated by the preparation of the Tyr(P)-containing peptides, Ala-Glu-Tyr(P)-Ser-Ala and Ser-Ser-Ser-Tyr(P)-Tyr(P). 相似文献