胆汁胆固醇对胆囊收缩素受体表达的影响

目的：探讨胆汁胆固醇对胆囊收缩素受体（CCK－R）表达的影响。方法 采用放射免疫分析法和受体放射配基结合法检测对照组、高胆固醇组、自然恢复组及治疗组豚鼠门静脉血CCK水平、胆囊CCK－R的最大结合容量（Bmax）和亲和力（Kd），同时观察空腹胆囊体积（FV）、胆囊胆汁量（FB）和餐后胆囊体积（RV）、胆囊胆汁量（RB）及胆囊收缩率（E％）、胆汁胆固醇浓度的变化。结果 与对照组比较，高胆固醇组豚鼠FV、FB增大（P＜0.05），RV、RB也增大，胆囊收缩率下降（P＜0.01），胆汁胆固醇浓度升高（P＜0.05），门静脉血CCK水平及CCK－R的Kd无改变，而CCK－R的Bmax下降（P＜0.01）；治疗组上述各项指标正常。结论 胆汁中的高胆固醇通过下调胆囊CCK－R表达而导致胆囊收缩功能障碍，降低胆汁高胆固醇浓度可以促进胆囊动力功能的恢复。     

Regional extraction of circulating norepinephrine, DOPA, and dihydroxyphenylglycol in humans

Dihydroxyphenylglycol (DHPG) is the main intraneuronal metabolite of the sympathetic neurotransmitter, norepinephrine (NE), and dihydroxyphenylalanine (DOPA) the immediate product of the rate-limiting step in catecholamine biosynthesis. Simultaneous measurements of regional rates of appearance (spillovers) of NE, DOPA, and DHPG in plasma have the potential to provide unique information about aspects of sympathoneural function but have not actually been measured in humans. In the present study, spillovers of DHPG, DOPA, and NE in the heart, head, leg, and lungs, were estimated from regional extraction fractions of infused [3H]-1-NE, DHPG, and [13C6]DOPA or unlabelled DOPA in humans during cardiac catheterization. There was little cardiac extraction of DHPG (7 +/- SEM 2%) or DOPA (8 +/- 4%) but substantial extraction of NE (69 +/- 4%). Values for cardiac spillover of DHPG and DOPA therefore were similar to values for the arteriovenous increment times plasma flow (arteriovenous production rate), whereas the cardiac spillover of NE averaged about 7-times the NE arteriovenous production rate. Cardiac DHPG spillover (28 +/- 3 ng/min) exceeded the spillovers of NE (9 +/- 2 ng/min) and DOPA (15 +/- 4 ng/min). In contrast, cranial DOPA spillover (159 ng/min) exceeded those of NE and DHPG by 8- and 2-fold and accounted for about 1/10 of the total spillover of DOPA into arterial plasma. In the femoral vascular bed, arteriovenous production rates of NE and DHPG were unrelated to femoral spillovers of NE and DHPG. Arterial and regional clearances of [13C6]DOPA were similar to those of unlabelled DOPA. The results suggest that (1) endogenous NE, DOPA, and DHPG all are released into the bloodstream by the heart, head, and limbs of humans; (2) DHPG and DOPA are not co-released with NE; (3) cardiac arteriovenous production rates of DOPA and DHPG can be used to indicate cardiac spillover of these catechols, whereas the cardiac NE arteriovenous production rate substantially underestimates cardiac NE spillover; and (4) estimates of limb spillover of NE and DHPG require concurrent measurements of the corresponding regional clearances.     

Antimalarial action of alloxan and 5,6-diamino-2,4-dihydroxy-pyrimidine in Plasmodium berghei

Three hours after iv administration of alloxan and 5,6-diamino-2,4-dihydroxy-pyrimidine to mice infected with chloroquine-sensitive (CS) and chloroquine-resistant (CR) strains of Plasmodium berghei, the 2 compounds showed remarkable antimalarial actions. Parasitemia in CS and CR infected mice were reduced by about 50%. Slight hemolysis was seen in mice treated with alloxan but not in mice treated with 5,6-diamino-2,4-dihydro-pyrimidine. Alloxan did not inhibit glutathione reductase activity and no alloxan-glutathione complex was produced. No relationship between the antimalarial effects of alloxan and hemolysis or GSH content were found. It is suggested that the antimalarial effects of the two agents may be due to the inhibition of dihydroorotic acid dehydrogenase.     

河北省中药混乱品种鉴别研究——6.蕲蛇及其伪品的鉴别

按照中国药典1985年版蕲蛇为蝰科动物五步蛇除去内脏的干燥体。近年在河北省的药村商品中,发现有游蛇科动物滑鼠蛇混入其中,充当蕲蛇。作者应用解剖、组织切片的方法,研究了蕲蛇与滑鼠蛇在形态组织上的鉴别特征。它们的主要区别在于:鳞片、体表花纹、牙齿、鼻骨的形态;椎骨的形态与组织特征。据此可以鉴别蕲蛇与滑鼠蛇的真伪。     

Rapid hypertensinogenic effect of lead: studies in the spontaneously hypertensive rat.

Chronic lead exposure may cause hypertension in normotensive rats. This hypertensinogenic effect has been attributed to perturbations in the renin-angiotensin axis, the contractile response of the vascular smooth muscle, or the intracellular Ca2+ homeostasis as a consequence of the inhibition of Na(+)-K(+)-ATPase activity. In this study we examined the short-term effect of lead exposure on blood pressure, plasma renin activity, vascular contractility, and renal Na(+)-K(+)-ATPase activity and abundance in the spontaneously hypertensive rat. Our data indicate that modest lead exposure caused blood pressure elevation within two weeks in this rat strain that is genetically susceptible to the development of hypertension. This rapid blood pressure-elevating effect did not appear to depend on the mechanisms described in hypertension associated with more chronic lead exposure listed above. This acute model provides an additional approach to the study of lead-induced hypertension.     

High-efficiency stable gene transfection using chloroquine-treated Chinese hamster ovary cells

We describe a highly efficient stable gene transfection procedure for Chinese hamster ovary (CHO) cells using a modification of the calcium phosphate-DNA coprecipitation method. We have found that treatment of CHO cells with chloroquine increases the efficiency of gene transfer by up to 20-fold (from approx. 0.01% to approx. 0.2%) when transfection is done using the pSV2-neo plasmid. The optimized transfection procedure requires that CHO cells to be incubated with calcium phosphate-DNA coprecipitate and chloroquine (100 µM) for a total of 16 h. By using high-molecular-weight human genomic DNA as a DNA source for transfection, we show that this procedure is equally efficient for stably transferring a much larger gene, such as the 49-kb human hypoxanthine phosphoribosyltransferase gene.