Flunarizine in Migraine Prophylaxis: An Indian Trial

Flunarizine, a calcium channel blocker is considered useful in migraine prophylaxis. We report the first Indian trial with this drug. Fifteen patients with migraine were studied in a 6 months double-blind, placebo-controlled crossover trial. Flunarizine was superior to placebo in reducing the severity and duration of the individual attacks though there was no statistically significant effect on frequency of migraine attacks. The side effects most frequently caused by flunarizine were weight gain and daytime sleepiness.     

The effect of chronic hexarelin administration on the pituitary–adrenal axis and prolactin

OBJECTIVE: With the development of growth hormone (GH) releasing agents and their use in human subjects, it is clear that these agents are not specific for GH release. More recent studies in humans have demonstrated acute increases in adrenocorticotrophic hormone (ACTH), cortisol and prolactin (PRL) after boluses of intravenous or subcutaneous GHRPs. The potential adverse effects of repeated episodes of transient hyperprolactinaemia and hypercortisolaemia during long-term therapy with growth hormone releasing peptides (GHRPs) and similar agents have raised concern. We have therefore assessed the impact of chronic hexarelin administration on the pituitary-adrenal axis and serum prolactin levels. DESIGN: Each subject received twice-daily subcutaneous hexarelin therapy (1.5 micrograms/kg body weight) for 16 weeks. The ACTH, cortisol and PRL responses to the morning subcutaneous injection of hexarelin were assessed. Hexarelin was administered at time 0 and blood samples were taken at -10, 0, 10, 20, 30, 40, 50, 60, 90, 120, 170 and 180 min. The ACTH and PRL responses were assessed at baseline and after 16 weeks of therapy. The cortisol response was assessed at baseline, 16 weeks and also 4 weeks after completion of hexarelin therapy. Basal levels of cortisol binding globulin (CBG), 24-h urinary free cortisol (UFC) estimations, thyroid stimulating hormone (TSH) and total thyroxine (TT4) were performed at baseline, weeks 16 and 20. RESULTS: The mean (+/- SEM) area under the cortisol curve (AUCCORT) at baseline, week 16 and week 20 were 1506 (+/- 77) nmol/l/h, 1222 (+/- 92) nmol/l/h and 1586 (+/- 58) nmol/l/h, respectively. There was a significant change in AUCCORT over the study period (P = 0.008). Compared with baseline, AUCCOPRT had decreased significantly (P < 0.05) after 16 weeks of hexarelin therapy. Four weeks after completion of hexarelin therapy, the AUCCORT increased significantly compared with AUCCORT at week 16 (P < 0.01) and was no longer significantly different from baseline values. There were no significant changes in UFC (P = 0.3), basal cortisol measurements (P = 0.19), area under the ACTH curve (AUCACTH) (P = 0.24) or CBG (P = 0.6) over the study period. The mean (+/- SEM) area under the PRL curve (AUCPRL) at the baseline and week 16 were 624 (+/- 82) mU/l/h and 641 (+/- 83) mU/l/h, respectively. There was no significant change in AUCPRL over the study period (P = 0.35). CONCLUSION: The present study demonstrates clearly that in this hexarelin dosage regimen, over-stimulation of the pituitary adrenal axis and prolactin secretion do not occur. In fact the impact of chronic hexarelin therapy on the pituitary-adrenal axis, i.e. decreased AUCCORT, contradict the findings reported after acute hexarelin administration and cannot be explained by changes in CBG. The lack of change in UFC, however, suggests that these changes are unlikely to be of clinical significance although the underlying mechanism requires further study.     

Jimson Weed Extract as a Protective Agent in Severe Organophosphate Toxicity

Treatment of patients following an organophosphate (OP) exposure can deplete a hospital's entire supply of atropine. Given the possibility of multiple severe exposures after a terrorist attack using OP nerve agents, there exists a need for either greater atropine stores or the development of alternative antidotes. Jimson weed (Datura stramonium) contains atropine and other anticholinergic compounds and is common and readily available. It is used recreationally for its central anticholinergic effects and is made easily into an extract by boiling the crushed seeds. The extract has rapid onset of effects and may be useful for treatment of OP poisoning. OBJECTIVES: To determine whether pretreatment with an easily stored and prepared Datura seed extract (DSE) will increase survival following a severe OP poisoning. METHODS: Datura stramonium seeds were collected, crushed, and then heated in water to make a 2-mg/mL atropine solution (100 seeds contain approximately 6 mg of atropine or 0.007 mg/seed). Male rats were randomized to pretreatment with either saline (n = 10) or 7.5 mg/kg DSE (n = 10) given as a single intraperitoneal injection 5 minutes prior to a subcutaneous injection of 25 mg/kg of dichlorvos. The endpoint was time to death recorded by a blinded observer. RESULTS: The Kaplan-Meier estimates of the 24-hour survival rate was 90% (95% CI = 56% to 100%) for the DSE-pretreated group and 10% (95% CI = 0% to 45%) for the control group. The log-rank test revealed a statistically significant longer survival for the Datura-treated animals (p = 0.0002). Median survival time was 22 minutes 30 seconds for the control group and greater than 24 hours for the DSE-pretreated group. CONCLUSIONS: Pretreatment with DSE significantly increases survival following severe dichlorvos exposure.     

Carrier-directed anti-hapten responses by b-cell subsets

The capacity of the trinitrophenyl (TNP) haptenic group, coupled to a series of chemically dissimilar carriers, to cross-stimulate putative T- dependent and T-independent murine B-cell subpepulations was determined by using an in vitro limiting dilution technique to generate primary IgM responses. It was found that TNP-Ficoll and TNP-dextran, two T- independent antigens with little or no polyclonal mitogenicity, stimulate the same population of anti-TNP precursors, which is distinct from the precursor population activated by TNP-bacterial lipopolysaccharide (LPS), a T-independent polyclonal mitogen, or TNP-horse erythrocytes (HRBC), a T-dependent antigen. On the other hand, TNP-LPS and TNP-HRBC activate the same precursor population, indicating that LPS can substitute for the T- cell signal in T-dependent B-cell responses, whereas nonmitogenic T- independent antigens cannot. However, the cumulative evidence from this and other laboratories strongly indicates that LPS and T-dependent antigens activate B cells by different mechanisms. Of particular interest, LPS is incapable of activating B cells responsive to weakly- or nonmitogenic T-independent antigens. Based on clonal burst size, T-dependent antigens are capable of inducing greater antigen-specific B-cell proliferation than T-independent antigens. However, TNP conjugates of Ficoll and dextran, which are relatively poor inducers of polyclonal B-cell activation, induced larger anti-TNP clones than did TNP-LPS, a strong polyclonal mitogen. The findings reinforce the evidence favoring existence of multiple B- cell subpopulations with distinctive activation pathways. They also strengthen the proposition that a given B-cell subset can be activated by more than one mechanism.     

血管内皮细胞生长因子受体KDR基因靶向RNA干扰质粒的构建

目的:应用RNA干扰技术设计构建针对血管内皮细胞生长因子受体KDR的小干扰RNA,并观察脂质体转染肺癌细胞A549后的干扰效果。方法:实验于2005-03/2006-01在沈阳医学院生物化学及分子生物学教研室完成。①设计针对KDR编码区有短发夹结构的3条mRNA序列,经退火成互补双链,克隆到pGCsi.H1/neo/GFP载体中构建3个重组质粒,分别命名为KDR-siRNA1、KDR-siRNA2和KDR-siRNA3。②设立5组:小干扰RNA组,分别转染KDR-siRNA1、KDR-siRNA2和KDR-siRNA3;阳性对照组,转染pGCsi.H1/neo/siGFP,该质粒载体中的插入序列为针对绿色荧光蛋白的小干扰RNA,不干扰待研究的内源性基因;阴性对照组,转染pGCsi.H1/neo/GFP/NON,该载体为不干扰任何内源性基因的小干扰RNA;空白对照组,转染pGCsi.H1/neo/GFP空载体;正常对照组,不进行任何转染。③对重组质粒进行酶切鉴定、DNA测序分析;脂质体法转染质粒至肺癌A549细胞株后,实时定量PCR检测KDRmRNA的水平变化;细胞计数法绘制细胞生长曲线。结果:①小干扰RNA表达载体的鉴定:KDR-siRNA1、KDR-siRNA2和KDR-siRNA3表达载体用限制性内切酶NdeⅠ和SmaⅠ进行单酶切后,均产生约713bp、5480bp和2403bp、3790bp两个片段,与预期结果相同。测序结果与设计的编码相应短发夹状KDR-小干扰RNA的寡核苷酸序列一致,证明KDR-小干扰RNA真核表达载体构建成功。②KDR-小干扰RNA对A549细胞中KDRmRNA水平的影响:与阳性对照组、阴性对照组、空白对照组和正常对照组的A549细胞相比,KDR-siRNA1,2,3表达载体转染后的A549细胞KDR基因表达水平均明显受到抑制,抑制率分别为64%、81%和72%,其中以KDR-siRNA2抑制作用最为明显。③KDR-小干扰RNA对A549细胞生长的影响:阳性对照组、阴性对照组、空白对照组、正常对照组的A549细胞生长趋势较为一致,且生长速度均明显高于转染3种KDR-小干扰RNA表达载体的A549细胞,从接种第2天开始差异有显著性意义(t=15.29～17.65,P均<0.01)。结论:血管内皮细胞生长因子受体KDR靶向RNA干扰重组质粒构建成功,该载体能有效抑制肺癌A549细胞KDR基因表达与细胞增殖。