Correlation between augmentative effects of leucovorin on 5-fluorouracil and thymidylate synthase inhibition

Background We studied the relationship between the augmentative effects of leucovorin (LV) on 5-fluorouracil (5-FU) and the inhibition rate of thymidylate synthase (TS) activity in Colon 26 murine colon carcinoma cells and L1210 murine leukemia cells. Methods In cytotoxic and TS inhibition studies, cells were exposed for 24 hours to varied concentrations of 5-FU alone or in combination with 1 or 10 μmol/L LV. Cytotoxicity was determined by colony forming efficiency or trypan blue dye exclusion, and TS inhibition rate was determined by [6-³H]-5-FdUMP binding assay. A growth inhibition curve was constructed for longer exposures. Results For tumor cell growth inhibition and cytotoxicity, the augmentative effect was observed when the lower 5-FU concentrations (0.1 μg/mL) were used. There was no difference in the effects between the low (1 μmol/L) and high (10 μmol/L) LV doses. Normally, TS enzyme levels rise acutely when cells are exposed to 5-FU. Both cell lines displayed an increase in TS after exposure to 5-FU. This exposure to 5-FU resulted in the maintenance of free enzyme. LV was able to increase the ternary complex and TS inhibition rate with little induction of TS, however, the inhibition rate was not dependent on doses of LV. Conclusions It was concluded that the augmentative effect of LV at a concentration of 0.1 μg/mL 5-FU occurred at the clinically achievable levels of 1 μmol/L of LV, and there was no difference in the effect between the low and high doses. TS was inhibited effectively by 5-FU and the addition of LV, without a marked induction of TS.     

Modulation of 5-fluorouracil with methotrexate and low-dose N-(phosphon-acetyl)-L-aspartate (PALA) is inactive in advanced pancreatic carcinoma

Purpose: To evaluate the effect of biochemical modulation by PALA and methotrexate on the therapeutic activity of 5-fluorouracil (5-FU) in patients with advanced pancreatic adenocarcinoma.Patients and methods: The treatment protocol consisted of phosphonacetyl-L-aspartate (PALA) 250 mg/m² i.v. 15-minute infusion followed by methotrexate 200 mg/m² i.v. 30-minute infusion on day 1 and 5-FU 600 mg/m² i.v. push on day 2. Folinic acid was given at 15 mg/m² p.o. every six hours for eight doses, starting 24 hours after methotrexate infusion. Cycles were repeated every two weeks.Results: Thirty patients with advanced chemotherapy-naive pancreatic cancer were included; 26 had measurable disease. Median age 56 years (27–72); median PS 1 (0–2). One PR (3.9%) was achieved; nine patients had stable disease. Median time to progression was 91 days. Median survival was 177 days and one year survival was 13.3% (4 of 30 patients). Treatment was well tolerated; diarrhea WHO grade 2 or 3 occurred in six patients; stomatitis WHO grade 2 and 3 in nine patients.Conclusions: Modulation of 5-FU by PALA and MTX given in this dose and schedule appears to be ineffective in patients with advanced pancreatic adenocarcinoma.     

Randomized trial comparing monthly low-dose leucovorin and fluorouracil bolus with weekly high-dose 48-hour continuous-infusion fluorouracil for advanced colorectal cancer: A Spanish Cooperative Group for Gastrointestinal Tumor Therapy (TTD) study

Purpose: The objective of this multicenter study was to compare the efficacy and toxicity profiles of a combination of 5-fluorouracil (5-FU) given by bolus injection together with intravenous leucovorin (LV) versus high-dose 5-FU in continuous infusion (CI) in the treatment of advanced colorectal cancer.Patients and methods: A total of 306 patients were randomized to receive either 5-FU 425 mg/m² given by bolus injection on days 1–5 plus intravenous (i.v.) LV 20 mg/m² every four to five weeks or 5-FU 3.5 g/m²/week in a 48-hour CI. Therapy was continued until disease progression. Second-line chemotherapy was allowed in both arms.Results: The response rates in 306 patients with measurable lesions were 19.2% (modulated arm) and 30.3% (CI arm, P < 0.05). The median progression-free survival times were 23.5 weeks (modulated arm) and 25 weeks (CI arm, P = NS). Median survival times were 42.5 weeks (modulated arm) and 48 weeks (CI arm, P = NS). There were no significant differences in grade 3–4 toxicity profiles but if we consider all grades we observed more mucositis in the modulated arm and more hand-foot syndrome in the CI arm.Conclusions: In terms of response rate, the continuous infusion regimen was more effective than the modulated regimen. There was no significant difference in survival and time to progression, and none in grade 3–4 toxicity.     

Activation of mouse microglial cells affects P2 receptor signaling

Microglial cells are the immunocompetent cells of the CNS, which are known to exist in several activation states. Here we investigated the impact of microglial activation on the P2 receptor-mediated intracellular calcium ([Ca(2+)](i)) signaling by means of fluo-3 based Ca(2+)-imaging. Cultured mouse microglial cells were treated with either astrocyte-conditioned medium to induce a ramified morphology or LPS to shift the cells toward the fully activated stage. The extracellular application of ATP (100 microM) induced a [Ca(2+)](i) elevation in 85% of both untreated and ramified microglial cells, whereas only 50% of the LPS-activated cells responded to the stimulus. To characterise the pharmacological profile of microglial P2 receptors we investigated the effects of various P2 agonists on [Ca(2+)](i) in cultured microglial cells. Untreated and ramified microglial cells demonstrated a very similar sensitivity to the different P2 agonists. In contrast, in LPS-activated microglia, a sharp decrease of responses to P2 agonist stimulation was seen. This indicates that microglial activation influences the capability of microglial cells to generate [Ca(2+)](i) signals upon P2 receptor activation.     

益生菌对急性胰腺炎大鼠肠道微生态及紧密连接的影响

目的 探讨经肠道补充益生菌对急性胰腺炎（AP）大鼠肠上皮细胞紧密连接、屏障功能及微生态的影响.方法 经胰管注射3%牛磺胆酸钠造成大鼠AP后,分别给予肠外营养（PN组）和PN＋益生菌（益生菌组）,持续5天;第6天处死大鼠,取腔静脉血、肺及肝组织和肠系膜淋巴结匀浆作细菌培养测细菌易位率;取末段回肠和结肠,采用免疫组织化学法测定其跨膜结合蛋白表达,电镜观察肠上皮细胞紧密连接超微结构;取盲肠内粪便作厌氧培养及细菌种群DNA指纹图谱分析.结果 益生菌组大鼠肠道内乳杆菌和双歧杆菌数量高于PN组（P＜0.05）,而潜在致病菌产气荚膜梭菌低于PN组（P＜0.05）,DNA指纹图谱也显示益生菌组优势菌群的基因条带和正常大鼠具有较高一致性,与PN组相比则有明显差异;益生菌组小肠和大肠跨膜结合蛋白的表达明显优于PN组（P=0.001,P=0.036）,肠上皮细胞紧密连接、微绒毛较完整;益生菌组大鼠的血、肺、肝、肠系膜淋巴组织的细菌易位率低于PN组（P=0.0413）.结论 益生菌能纠正AP大鼠PN时肠道菌群紊乱,增加肠上皮跨膜结合蛋白表达,维持肠上皮紧密连接,减少细菌易位。     

谷氨酰胺和重组人生长激素对门静脉高压症患者术后肠黏膜屏障功能的影响

目的研究单独或联合应用谷氨酰胺（Gln）和重组人生长激素（rhGH）对门静脉高压症患者术后肠黏膜屏障功能的影响。方法将29例肝硬化门静脉高压症接受手术治疗的患者随机分为4组：Gln组（n=6）、rhGH组（n=8）、Gln＋rhGH组（n=7）和对照组（n=8）。术后3天开始进行等氮、等热量的全胃肠外营养（TPN）支持，持续7天。对患者手术前、后的尿乳果糖／甘露醇（L／M）、十二指肠降段黏膜绒毛高度及陷窝深度进行测定。结果Gln＋rhGH组L／M升高的幅度显著小于对照组（P〈0．05），Gln和rhGH组与对照组比较差异无显著性。Gln＋rhGH组肠黏膜绒毛高度和陷窝深度均大于对照组（P〈0．05），Gln和rhGH组与对照组比较差异无显著性（P〉0．05）。Gln＋rhGH组术后绒毛高度及陷窝深度均显著大于术前（P〈0．05）；对照组术后绒毛高度小于术前（P〈0．05），陷窝深度差异无显著性（P〉0．05）；Gln和rhGH组手术前、后绒毛高度及陷窝深度差异无显著性（P〉0．05）。结论联合应用Gln和rhGH能降低门静脉高压症患者术后肠壁通透性并维护肠黏膜形态学完整性，单独应用Gln或rhGH无此作用。     

Effects of tetrandrine on phenotypic modulation of vascular smooth muscle cells and expression of p38 MAPK as well as MKP-1 after intimal injury of rabbit carotid arteries

Objective： To study the effects of tetrandrine （Tet） on phenotypic modulation of vascular smooth muscle cells （VSMCs） and expression of p38 mitogen-activated protein kinase （p38MAPK） as well as mitogen-activated protein kinase phosphatase-1 （MKP-1） after vascular intimal injury. Methods： HE staining was used to analyze vascular morphology of sham-injured group, injured group and Tet-treated group at day 28. lmmunohistochemistry, Western blot and RT-PCR were respectively used to detect the expression change of smooth muscle a-actin （SMa-actin）, proliferation cell nuclear antigen （PCNA）, p38MAPK and MKP-1 of injured group and Tet group at days 7, 14 and 28 after balloon injury. Results： ① All layers of vascular wall in sham-injured group were intact at day 28. The neointimal area was significantly increased and the lumen area notably decreased in injured group at day 28. The neointimal proliferation in Tet treated group was less than that in injured group, and the lumen area of Tet group was significantly increased than that of injured group at day 28. ②Compared with the injured group, the expression of SMa-actin, PCNA, p38MAPK and MKP-1 of vascular wall in Tet group was no difference, and the neointimal proliferation condition was also basically as same as injured group at day 7 after injury. The expression of PCNA and p38MAKP in Tet group was obviously lower than that in injured group, and the expression of MKP-1 in Tet group was obviously higher than that in injured group at days 14 and 28 after injury. The expression of SMa-actin in Tet group was slightly higher than that in injured group at days 14 and 28 after injury. Conclusions： Tet could reduce neointimal proliferation by inhibiting VSMCs phenotypic modulation and p38MAPK signaling transduction pathway as well as its down regulation.     

Living donor small bowel transplantation: Literature review 2003–2006

The experience with living donors for intestinal transplantation is limited. However, Intestinal Registry data suggest that the outcomes of the procedure are comparable with those obtained with intestinal transplant from deceased donors. In selected cases, this strategy may have a role in the treatment of patients with irreversible intestinal failure suffering life-threatening complications from total parenteral nutrition. The present review covers most of the published data on this topic between 2003 and 2006, with special reference to living donor intestinal transplantation of pediatric recipients.     

Glucocorticoid enhancement of memory consolidation in the rat is blocked by muscarinic receptor antagonism in the basolateral amygdala

Glucocorticoid-induced memory enhancement is known to depend on beta-adrenoceptor activation in the basolateral amygdala (BLA). Additionally, inactivation of muscarinic cholinergic receptors in the rat amygdala blocks memory enhancement induced by concurrent beta-adrenergic activation. Together, these findings suggest that glucocorticoid-induced modulation of memory consolidation requires cholinergic as well as adrenergic activation in the BLA. Two experiments investigated this issue. The first experiment examined whether blockade of muscarinic cholinergic receptors in the BLA with atropine alters the memory-enhancing effects of the systemically administered glucocorticoid dexamethasone. Dexamethasone (0.3, 1.0 or 3.0 mg/kg, s.c.) administered to rats immediately after inhibitory avoidance training produced dose-dependent enhancement of 48-h retention. Concurrent bilateral infusions of the muscarinic cholinergic antagonist atropine (0.5 microg in 0.2 microL per side) into the BLA blocked the memory enhancement. The second experiment investigated whether the BLA is a locus of interaction between glucocorticoid and muscarinic activation. The specific glucocorticoid receptor (GR or type II) agonist RU 28362 (1.0, 3.0 or 10 ng) was infused into the BLA either alone or together with atropine immediately after training. The GR agonist produced dose-dependent memory enhancement and atropine blocked the memory enhancement. These findings indicate that muscarinic cholinergic activation within the BLA is critical for enabling glucocorticoid enhancement of memory consolidation and that enhancement of memory induced by GR activation in the BLA requires cholinergic activation within the BLA.     

针刺调节与G蛋白相关性探讨

目的:探讨针刺对机体调节与G蛋白呈相关性.方法:通过对针刺后机体内某些化学物质的改变,及针刺对镇痛、防卫免疫、对机体的调节作用与G蛋白的关系进行综合分析.结果:针刺经穴引起的化学物质的变化,继而产生的针刺调节和G蛋白亚型、数量的变化有密切关系.结论:针刺调节和G蛋白呈相关性,G蛋白的变化可能是针刺对机体良性调节的作用机制之一.