Interaction of metal oxide nanoparticles with lung surfactant protein A

The alveolar lining fluid (ALF) covering the respiratory epithelium of the deep lung is the first biological barrier encountered by nanoparticles after inhalation. We here report for the first time significant differences for metal oxide nanoparticles to the binding of surfactant protein A (SP-A), the predominant protein component of ALF. SP-A is a physiologically most relevant protein and provides important biological signals. Also, it is involved in the lung’s immune defence, controlling e.g. particle binding, uptake or transcytosis by epithelial cells and macrophages. In our study, we could prove different particle-protein interaction for eight different nanoparticles, whereas particles of the same bulk material revealed different adsorption patterns. In contrast to other proteins as bovine serum albumin (BSA), SP-A does not seem to significantly deagglomerate large agglomerates of particles, indicating different adsorption mechanisms as in the well-investigated model protein BSA. These findings may have important consequences for biological fate and toxicological effects of inhaled nanomaterials.     

Protective effects of Passiflora alata extract pretreatment on carbon tetrachloride induced oxidative damage in rats.

The leaf extract of Passiflora alata Dryander (P. alata) has been demonstrated to possess antioxidant activity in vitro. The aim of this study was to investigate the effects of P. alata leaf extract pretreatment on carbon tetrachloride-treated rats. Male Wistar rats were randomly allocated into four groups: group 1 (control - vehicle), group 2 and 3 (P. alata extract - 1 and 5mg/kg, respectively) and group 4 (trolox - 0.18mg/kg). Rats received daily pretreatment by oral gavage for 30 days followed by a single dose of CCl(4) (3ml/kg i.p. in vegetable oil) on the 30th day and were killed after 6h. The pretreatment with the P. alata extract provided significant protection to liver, evidenced by lower degree of necrosis, decreased lipid peroxidation (TBARS) and higher catalase and superoxide dismutase activities. Additionally, pretreated-rats with P. alata (5mg/kg) showed significantly decreased cardiac TBARS levels. Our results indicate that a low oral dose of P. alata leaf extract has both hepato and cardioprotective effects on rats treated with CCl(4).     

新生儿缺氧缺血性脑病患儿外周单个核细胞CD25 mRNA表达

目的:探讨新生儿缺氧缺血性脑病(HIE)患儿外周血单个核细胞(PBMC)中CD25 mRNA表达。方法:以管家基因甘油醛-3-磷酸脱氢酶(GAPDH)为参照,应用Real-time PCR法检测新生儿HIE患儿及足月正常新生儿出生后第1、7天外周血CD25 mRNA水平,以lg cDNA/lg GAPDH比值代表其最终mRNA水平。结果:HIE患儿生后第1天静息期和诱导期CD25 mRNA水平分别为0.72±0.19和1.12±0.23,与正常对照组相比,差异有显著性(P<0.05);随着通气、换气等综合性治疗时间的延长,患儿缺氧缺血症状逐步改善,生后第7天静息期和诱导期CD25 mRNA水平分别为1.02±0.22和2.02±0.32,与正常对照组相比,差异无显著性(P>0.05)。其中HIE(重度)患儿静息期和诱导期CD25 mR-NA水平均较低,与正常对照组相比,差异有显著性(P<0.05)。结论:HIE患儿存在一定程度的细胞免疫功能紊乱,主要表现为外周血CD25 mRNA水平降低,并与HIE严重程度有关。     

Structure-activity relationship of neurokinin A(4-10) at the human tachykinin NK(2) receptor: the effect of amino acid substitutions on receptor affinity and function

A structure-activity study of the neurokinin A (NKA) fragment NKA(4-10) was performed to investigate the importance of amino acid residues for receptor efficacy, potency and affinity at the NK(2) receptor in human colon circular muscle. Fourteen analogs of NKA(4-10) were produced with substitutions at positions 4, 5, 7, 9 and/or 10 of NKA. Their potencies were determined by in vitro contractile responses and affinities by radioligand binding using [125I]NKA. Functional potency was enhanced 8-fold by single amino acid substitutions with Lys(5) and MeLeu(9) but not significantly altered by substitutions Glu(4), Arg(5), His(5) and Nle(10). The multiply-substituted analogs [MeLeu(9),Nle(10)]NKA(4-10), [Lys(5),MeLeu(9),Nle(10)]NKA(4-10) and [Lys(5),(Tyr(7)),MeLeu(9),Nle(10)]NKA(4-10) displayed 6-9-fold increase in potency. Although [Arg(5),Nle(10)]NKA(4-10) was similar in potency to NKA(4-10), it was the only analog to show significantly reduced efficacy. All analogs were able to compete fully for [125I]NKA binding. [Lys(5),MeLeu(9)]NKA(4-10), [MeLeu(9),Nle(10)]NKA(4-10), [Lys(5),Nle(10)]NKA(4-10) and analogs containing single substitutions with Glu(4), Arg(5), Lys(5) and MeLeu(9) displayed significantly higher affinity, whereas those with Nle(10) and [Glu(4),Nle(10)] substitutions showed significantly lower affinity than NKA(4-10). There was a positive correlation (r=0.63) between binding affinity and functional potency, which was markedly improved (r=0.95) by removal of three analogs: [Lys(5),MeLeu(9),Nle(10)]NKA(4-10), [Lys(5),Tyr(7),MeLeu(9),Nle(10)]NKA(4-10) and [Lys(5),Tyr(I(2))(7),MeLeu(9),Nle(10)]NKA(4-10). These exhibited similar binding affinities to that of NKA(4-10) but were more potent in functional studies, possibly indicating a different mechanism of receptor interaction. In conclusion, substitution of Ser(5) with Lys, and/or N-methylation of Leu(9), were the most effective changes to increase functional and binding potency of NKA(4-10) at the human colon NK(2) receptor.     

Reverse geometrical selectivity in glucuronidation and sulfation of cis- and trans-4-hydroxytamoxifens by human liver UDP-glucuronosyltransferases and sulfotransferases

The phenolic active metabolites, cis-4-hydroxytamoxifen (cis-HO-TAM) and trans-4-hydroxytamoxifen (trans-HO-TAM), of the anti-breast-cancer drug, trans-tamoxifen (TAM), were geometrically selectively glucuronidated in the manner of cis>trans by microsomes and sulfated in the manner of trans>cis by cytosol from the liver of 10 human subjects (7 females and 3 males). There was a large individual difference in the microsomal glucuronidation of cis-HO-TAM, which correlated well with glucuronidation of 4-hydroxybiphenyl by human liver microsomes. However, there was only a slight correlation between the glucuronidation of cis-HO-TAM and trans-HO-TAM or 4-nitrophenol (NP). A small individual difference was observed for the human liver cytosolic sulfation of trans-HO-TAM, which correlated well with the sulfation of NP. Recombinant human UDP-glucuronosyltransferase (UGT)2B15 catalyzed the cis-selective glucuronidation of geometrical isomers of HO-TAM. UGTs1A1, 1A4, 1A9 and 2B7 had weak activity toward HO-TAMs with a much smaller cis-selectivity than did UGT2B15. UGTs1A3 and 1A6 had no detectable activity toward these substrates. Among the four known major sulfotransferases (SULTs) occurring in the human liver, SULT1A1 was strongly suggested to play the most important role in the hepatic cytosolic trans-selective sulfation of HO-TAM isomers. A good correlation was observed between the hepatic cytosolic sulfation of trans-HO-TAM and NP, a standard substrate for SULT1A1. SULT1E1 had slight activity toward the HO-TAMs. SULTs1A3 and 2A1 had no detectable activity toward HO-TAMs.