芬太尼与瑞芬太尼用于小儿气管异物取出术的对比研究

目的比较丙泊酚复合芬太尼或瑞芬太尼的全静脉麻醉用于小儿气管异物取出术的安全性和有效性。方法选择280例择期行气管异物取出术的患儿,年龄1~3岁,随机分为两组:芬太尼组(F组,n=140),给予丙泊酚2.00~3.00 mg/kg、芬太尼2.00μg/kg行麻醉诱导,丙泊酚200.00~500.00μg/(kg·min)泵注维持麻醉;瑞芬太尼组(R组,n=140),给予丙泊酚2.00~3.00 mg/kg、瑞芬太尼1.00~1.50μg/kg行麻醉诱导,丙泊酚200.00~500.00μg/(kg·min)、瑞芬太尼0.10~0.20μg/(kg·min)维持麻醉。两组患儿均保留自主呼吸。观察置镜前(T_1)、置镜后1 min(T_2)、3 min(T_3)、退镜后3 min(T_4)、10 min(T_5)的脉搏氧饱和度(Sp O_2)及退镜后(T_6)的呼气末二氧化碳分压(P_(ET)CO_2),记录置镜过程中体动、呛咳、屏气、低氧血症的发生情况以及诱导时间、手术时间、苏醒时间和静脉药物用量。结果两组的Sp O_2在各时点均在正常范围,但R组Sp O_2在T_(2~5)明显高于F组(P<0.05)。T_6时R组P_(ET)CO_2低于F组(P<0.05)。R组置镜过程中体动、呛咳的发生率与F组相比差异无统计学意义(P>0.05),而屏气、低氧血症发生率均低于F组(P<0.05)。R组诱导和苏醒时间均明显低于F组(P<0.05),手术时间和丙泊酚用量两组比较差异无统计学意义(P>0.05),芬太尼用量明显多于瑞芬太尼(P<0.05)。结论丙泊酚复合芬太尼或瑞芬太尼在气管异物取出术中安全有效,但丙泊酚复合瑞芬太尼可提供更稳定的氧合、诱导苏醒更快及减少术中不良反应的发生。

右美托咪定用于小儿内镜下腺样体切除术的临床效果

目的探讨右美托咪定用于小儿腺样体切除术中患儿的应激反应和对术后镇痛、镇静效果的影响。方法选择择期行内镜下腺样体切除术的患儿91例,年龄3~7岁,随机分为右美托咪定组(D组,n=45)和生理盐水组(C组,n=46)。在麻醉诱导前D组给予右美托咪定0.50μg/kg静脉泵注10 min,C组给予同等体积生理盐水静脉泵注10 min。记录右美托咪定给药前(T_(0))、气管插管时(T_(1))、手术开始即刻(T_(2))、气管拔管时(T_(3))的平均动脉压(MAP)、心率(HR),以及拔管后5 min(T_(4))、拔管后30 min(T_(5))、拔管后1 h(T_(6))的小儿术后疼痛评分(CHIPPS)和Ramsay镇静评分。统计麻醉过程中丙泊酚、舒芬太尼和瑞芬太尼的使用量。结果T_0时点两组患儿MAP和HR比较,差异无统计学意义,T_(1)~T_(3)时点D组的MAP和HR均低于C组(P<0.05);与C组比较,T_(4)~T_(6)时点D组的CHIPPS疼痛评分明显降低(P<0.05),而T_(4)~T_(6)时点D组的Ramsay镇静评分明显增高(P<0.05)。两组患者丙泊酚、舒芬太尼和瑞芬太尼用量比较,差异均无统计学意义(P>0.05)。结论术前给予0.50μg/kg右美托咪定可减轻内镜下腺样体切除术患儿的应激反应、缓解术后疼痛并维持良好的镇静效果,值得临床推广应用。

围术期不同保温措施对新生儿复苏质量的影响

目的比较围术期常规保温措施与综合保温措施对新生儿复苏质量的影响。方法纳入60例骶管阻滞复合全身麻醉下择期手术的足月新生儿,将其分为常规保温措施组(C组30例)和综合保温措施组(I组30例)。记录两组术前、术中及术后的肛温值,同时评估两组低体温发生情况;记录手术时间、麻醉后复苏室(PACU)的复苏时间及拔管后相关并发症的发生情况。结果两组术前肛温值比较差异无统计学意义(P>0.05),术中及术后肛温值I组高于C组(P <0.05)。与术前肛温值比较,两组术中、术后肛温值均降低(P <0.05)。I组围术期未发生低体温,而C组术中、术后均发生轻、中度低体温。两组手术时间比较差异无统计学意义(P>0.05),I组PACU复苏时间短于C组(P <0.05)。两组相关并发症(如舌根后坠、呼吸暂停、低血压)比较,差异无统计学意义(P>0.05),而寒战发生率C组高于I组(P <0.05)。结论骶管阻滞联合全麻手术的新生儿对体温变化极为敏感,围术期需采用综合保温措施来改善新生儿PACU麻醉复苏质量。

丙泊酚联合骶管阻滞对下腹部麻醉患儿的影响

目的探究丙泊酚联合骶管阻滞对下腹部麻醉患儿血流动力学及血清人β淀粉样蛋白1-42(Aβ_(1-42))、人β淀粉样蛋白1-40(Aβ_(1-40))的影响。方法选取2016年2月-2017年4月在儿童医院行下腹部手术的患儿73例作为研究对象,根据随机数字表法分为对照组(36例)和观察组(37例)。对照组患儿采用氯胺酮﹑丙泊酚复合静脉麻醉的麻醉方式,观察组患儿采用丙泊酚联合骶管阻滞的麻醉方式。比较两组患儿的麻醉效果﹑血流动力学指标﹑血清Aβ_(1-42)和Aβ_(1-40)水平及不良反应的发生情况。结果观察组患儿的麻醉诱导时间、苏醒时间均短于对照组(P<0.05);观察组与对照组收缩压、舒张压及心率组内、组间及时间变化趋势有差异(P<0.05),观察组变化趋势较小;麻醉前后两组患儿Aβ_(1-40)和Aβ_(1-42)水平的比较,差异均无统计学意义(均P>0.05);观察组患儿各种不良反应的发生率均低于对照组(P<0.05)。结论丙泊酚联合骶管阻滞对行下腹部手术的患儿进行麻醉时,麻醉效果好,对血流动力学及血清Aβ_(1-42)、Aβ_(1-40)的影响小,因而发挥作用更为平稳、且不良反应的发生率低,值得推广应用。

肥胖对全身麻醉手术患儿罗库溴铵药效动力学指标的影响研究

目的研究肥胖对全身麻醉手术患儿罗库溴铵药效动力学指标的影响研究。方法选取2014年12月—2015年12月南京医科大学附属儿童医院进行手术治疗的96例患儿,按体重指数(BMI)分为肥胖组(A组,BMI≥95%)、正常组(B组,BMI 50%～95%)及低体重组(C组,BMI≤50%),每组32例。3组注入巴比妥钠建立静脉通道后,进行诱导麻醉,5 s内推注罗库溴铵。记录患儿苏醒指标(首次自主恢复指数、第1次不自主体动时间及首次睁眼时间)、肌松监测指标起效时间、无反应期及恢复指数,观察其不良反应情况。结果3组3项苏醒指标和恢复指数比较,差异无统计学意义(P>0.05);A组起效时间最短(P <0.05),C组无反应期最短、肌松药用量最少(P <0.05);3组均无不良反应发生,恢复良好。结论肥胖症能加快全身麻醉手术患儿罗库溴铵的药物起效时间、延长作用时间,是影响肌松药药效的重要因素之一;在治疗过程中应注意对患儿体重指标的监测,进行个体化治疗。

Clinical features and outcomes of patients with severe acute pancreatitis complicated with gangrenous cholecystitis

BACKGROUND: The effects of gangrenous cholecystitis (GC) and consequent surgical interventions on the clinical outcomes and prognosis of patients with severe acute pancreatitis are not clear. The present study was to characterize the clinical outcomes of patients with severe acute pancreatitis complicated with GC. METHODS: We retrospectively analyzed 253 consecutive patients hospitalized for acute pancreatitis in intensive care unit. Among them, 68 were diagnosed as having severe acute pancreatitis; 10 out of the 68 patients had GC. We compared these 10 patients with GC and 58 patients without GC. The indices analyzed included sepsis/septic shock, pancreatic encephalopathy, acute respiratory distress syndrome, acute renal failure, multiple organ dysfunction syndrome, and death. RESULTS: Specific CT images of GC in patients with severe acute pancreatitis included enlarged and high-tensioned gallbladder, wall thickening, lumenal emphysema, discontinuous and/or irregular enhancement of mucosa, and pericholecystic effusion. The rates of severe sepsis/septic shock (70.0% vs 24.1%, P<0.01), pancreatic encephalopathy (50.0% vs 17.2%, P<0.05), acute respiratory distress syndrome (90.0% vs 41.4%, P<0.01), multiple organ dysfunction syndrome (70.0% vs 24.1%, P<0.01), acute renal failure (40.0% vs 27.6%, P<0.05), and death (40.0% vs 13.8%, P<0.05) were significantly higher in patients with GC than in those without GC.CONCLUSION: CT scans can help to identify early GC in patients with severe acute pancreatitis; early diagnosis and intervention for patients with GC can reduce morbidity and mortality.

Activation of paternally expressed imprinted genes in newly derived germline-competent mouse parthenogenetic embryonic stem cell lines

单性生殖的胚胎的茎(足) 细胞为学习位于印的 genomic 下面的分子的机制提供一个珍贵试管内模型系统。然而，足房间的 thepluripotency 和父亲一般地表示的印的基因的表示侧面一直不是充分探索了。在这研究，三根老鼠足房间线被建立，在扩大文化的这些房间的区别潜力被评估。无差别的房间有正常核型和同型结合的染色体，并且表示了 ES-cell-specific 分子的标记。房间在超过 50 个段落以后仍然保持无差别并且展出了 pluripotentdifferentiation 能力。确定的 ES 房间的所有三根线生产了 teratomas；ES 房间的二根线生产了怪物和细菌线传播。而且，在这些房间的父亲一般地表示的印的基因 Snrpn， U2af1-rs1， Peg3，影响， Zfp127， Dlk1 和 Mest 的激活被检测。父亲一般地表示的印的基因被发现在单性生殖的联盟者的胚囊阶段被表示的一些激活胚胎试管内，他们的表示水平与扩大的足细胞培养增加了。而且，我们在足房间的这些父亲一般地表示的印的基因的激活在 ther 的甲基化与一个变化被联系的数据表演鼓舞了差别 methylated 区域。这些调查结果为足房间的 thepluripotency 提供直接证据并且在足房间表明在脱氧核糖核酸甲基化模式和父亲一般地表示的印的基因的激活之间的协会。因此，确定的 ES 房间线为在哺乳动物的开发学习 epigenetic 规定提供一个珍贵模型。

γ-Aminobutyric acid transporter (GAT1) overexpression in mouse affects the testicular morphology

γ-Aminobutyric acid and GABAergic receptors were previously reported to be distributed in reproductive systems besides CNS and predicted to participate in the modulation of testicular function. γ-Aminobutyric acid transporter was implicated to be involved in this process. However, the potential role of γ-aminobutyric transporter in testis has not been explored. In this study, we investigated the existence of mouse γ-aminobutyric acid transporter subtype I (mGAT1) in testis. Wild-type and transgenic mice, which overexpressing mGAT1 in a variety of tissues, especially in testis, were primarily studied to approach the profile of mGAT1 in testis. Mice with overexpressed mGAT1 develop normally but with reduced mass and size of testis as compared with wild-type. Testicular morphology of transgenic mice exhibited overt abnormalities including focal damage of the spermatogenic epithelium accompanied by capillaries proliferation and increased diameter of seminiferous tubules lumen. Reduced number of spermatids was also found in some seminiferous tubules. Our results clearly demonstrate the presence of GAT1 in mouse testis and imply that GAT1 is possibly involved in testicular function.

A mRNA molecule encoding truncated excitatory amino acid carrier l(EAAC1)protein(EAAC2)is transcribed from an independent promoter but not analternative splicing event

Glutamate transporter EAAC1 removes excitatory neurotransmitter in central nervous system, and alsoabsorbs glutamate in epithelia of intestine, kidney, liver and heart for normal cell growth. When a mousecDNA was screened using EAAC1 cDNA fragment as probe in our lab, a transcript (GenBank U75214)encoding an EAAC1 protein with 148 residues truncated at N-terminal was cloned and named as EAAC2.Sequence analysis shows that EAAC2 has it's own start code and unique 5'UTR that is different from that ofEAAC1. A mouse genomic library was screened and a positive clone including EAAC1 CDS was sequenced(GenBank AF 322393) and indicates that normal EAAC1 transcript (GenBank U73521) is transcribed from10 exons in terms of exon I, II, III, IV, V, VI, VII, VIII, IX, X, and EAAC2 transcript is consisted by exonsfrom IV to IX as same as that of EAAC1 and with its unique exonβ upstream to exon IV and exon δdownstream to IX. EAAC2 transcript has a cluster of transcriptional start sites not overlapping with thetranscriptional start sites of EAAC1. These results indicate that EAAC2 is transcribed from an independentpromoter but not an alternative splicing event.

Val 70, Phe 72 and the last seven amino acid residues of C-terminal are essential to the function of norepinephrine transporter

The norepinephrine transporter(NET) is a member of the Na+/Cl- dependent neurotransmitter transporter family and constitutes the target of several clinically important antidepressants. To delineate the critical amino acid residues and the function of C-terminal in regulating transport activity of NET, here we constructed two site mutants (V70F, F72V; V70I, F72V) and one C-terminal truncated mutant (△611-617). The wild type and mutants of NET were expressed in Xenopus oocytes by injection of their cRNA. We found that all of these mutants lost their transport activity. These results indicate that the amino acid residues of V70 and F72 3 and the last seven amino acids of C-terminal are essential to the transport activity of NET.

Transgenic mice overexpressingγ-aminobutyric acid transporter subtypeⅠ develop obesity

Transgenic mice ubiquitously overexpressing murine γ aminobutyric acid transporter subtype Ⅰ were created. Unexpectedly, these mice markedly exhibited heritable obesity, which features significantly increased body weight and fat deposition. Behavioral examination revealed that transgeinc mice have slightly reduced spontaneous locomotive capacity and altered feeding pattern. Tills preliminary finding indicates that the inappropriate level of γ-aminobutyric acid transporters may be directly or indirectly involved in the pathogenic mechanism underlying certain types of obesity.

Analysis of the 5' flanking sequence of the human norepinephrine transporter gene

The human norepinephrine transporter(NET) gene was cloned and structurally analyzed. The far 5’ fragment containing exon 1 (a non-coding exon) and exon 2 was sequenced. The transcription start site of the gene in human brain stem tissue was determined by primer extension analysis. It was found that the gene could be transcribed from multiple starting points. The 5’ flanking sequence contains a proximal G-C rich region, one possible GSG elemeflt and several SP1 sites. However it does not contain TATA box and CAAT box motifS. Gel shift analysis with nuclear extracts from different tissues of mouse shows that the G-C rich region may be involved in tissue specific expression of the gene.

Deletion of Gpr128 results in weight loss and increased intestinal contraction frequency

AIM:To generate a Gpr128 gene knockout mouse model and to investigate its phenotypes and the biological function of the Gpr128 gene.METHODS:Bacterial artificial chromosome-retrieval methods were used for constructing the targeting vector.Using homologous recombination and microinjection technology,a Gpr128 knockout mouse model on a mixed 129/BL6 background was generated.The mice were genotyped by polymerase chain reaction(PCR)analysis of tail DNA and fed a standard laboratory chow diet.Animals of both sexes were used,and the phenotypes were assessed by histological,biochemical,molecular and physiological analyses.Semi-quantitative reverse transcription-PCR and Northern blotting were used to determine the tissue distribution of Gpr128mRNA.Beginning at the age of 4 wk,body weights were recorded every 4 wk.Food,feces,blood and organ samples were collected to analyze food consumption,fecal quantity,organ weight and constituents of the blood and plasma.A Trendelenburg preparation was utilized to examine intestinal motility in wild-type(WT)and Gpr128-/-mice at the age of 8 and 32 wk.RESULTS:Gpr128 mRNA was highly and exclusively detected in the intestinal tissues.Targeted deletion of Gpr128 in adult mice resulted in reduced body weight gain,and mutant mice exhibited an increased frequency of peristaltic contraction and slow wave potential of the small intestine.The Gpr128+/+mice gained more weight on average than the Gpr128-/-mice since 24 wk,being 30.81±2.84 g and 25.74±4.50 g,respectively(n=10,P<0.01).The frequency of small intestinal peristaltic contraction was increased in Gpr128-/-mice.At the age of 8 wk,the frequency of peristalsis with an intraluminal pressure of 3 cmH2O was 6.6±2.3 peristalsis/15 min in Gpr128-/-intestine(n=5)vs 2.6±1.7peristalsis/15 min in WT intestine(n=5,P<0.05).At the age of 32 wk,the frequency of peristaltic contraction with an intraluminal pressure of 2 and 3 cmH2O was 4.6±2.3 and 3.1±0.8 peristalsis/15 min in WT mice(n=8),whereas in Gpr128-/-mice(n=8)the frequency of contraction was 8.3±3.0 and 7.4±3.1peristalsis/15 min,respectively(2 cmH2O:P<0.05 vs WT;3 cmH2O:P<0.01 vs WT).The frequency of slow wave potential in Gpr128-/-intestine(35.8±4.3,36.4±4.2 and 37.1±4.8/min with an intraluminal pressure of 1,2 and 3 cmH2O,n=8)was also higher than in WT intestine(30.6±4.2,31.4±3.9 and 31.9±4.5/min,n=8,P<0.05).CONCLUSION:We have generated a mouse model with a targeted deletion of Gpr128 and found reduced body weight and increased intestinal contraction frequency in this animal model.

Molecular cloning and structural analysis of human norepinephrine transporter gene(NETHG)

A cDNA molecule encoding a major part of the hu-man Norepinephrine transporter(hNET) was synthesized by means of Polymerase Chain Reaction(PCR) technique and used as a probe for selecting the human genomic NET gene. A positive clone harbouring the whole gene was ob-tained from a human lymphocyte genomic library through utilizing the "genomic walking" technique. The clone, des-ignated as phNET, harbours a DNA fragment of about 59 kb in length inserted into BamH Ⅰ site in cosmid pWE15.The genomic clone contains 14 exons encoding all amino acid residues in the protein. A single exon encodes a dis-tinct transmembrane domaill, except for transmembrane domain 10 and 11, which are encoded by part of two ex-ons respectively, and exon 12, which encodes part of do-main 11 and all of domain 12. These results imply that there is a close relationship between exon splicing of a gene and structural domains of the protein, as is the case for the human γ-aminobutyric acid transporter(hGAT) and a number of other membrane proteins.

Papillary thyroid microcarcinoma with contralateral lymphatic skip metastasis and breast cancer: A case report

BACKGROUND The recognized pattern of cervical lymph node metastasis(CLNM)of papillary thyroid carcinoma involves a stepwise route.Contralateral lymph node skip metastasis is very rare.In addition,the patient in our case report also suffered from a breast carcinoma accompanied by left supraclavicular lymphadenopathy,which made it difficult to distinguish the origin of the CLNM.Based on this case,we recommended that more detailed physical and imaging examinations are needed for patients with uncommon cervical lymphatic metastasis of primary cancer.CASE SUMMARY A 53-year-old women was admitted to the hospital for a neck mass in the left cervical region that had existed for 2 mo.The neck mass was suspected to be an enlarged lateral LN originating from papillary thyroid microcarcinoma of the contralateral thyroid lobe,according to ultrasound and ultrasound-guided fine needle aspiration biopsy.The patient underwent total thyroidectomy and radical cervical LN dissection.Postoperative pathology confirmed the diagnosis of papillary thyroid microcarcinoma with contralateral lymphatic skip metastasis.Unfortunately,a breast cancer was discovered 4 mo later,which was accompanied by ipsilateral supraclavicular LN metastasis.She accepted neoadjuvant chemotherapy and subsequent left modified radical mastectomy for treatment.The patient is currently receiving postoperative radiotherapy,and no local recurrence was observed in the 6-mo follow-up after surgery.CONCLUSIONWe present a rare case of papillary thyroid microcarcinoma with contralateral lymphatic skipmetastasis and breast cancer with supraclavicular lymphatic metastasis.

Comparative Analysis of Protein Expression Concomitant with DNA Methyltransferase 3A Depletion in a Melanoma Cell Line

DNA methyltransferase 3A (Dnmt3a), a de novo methyltransferase, has attracted a great deal of attention for its important role played in tumorigenesis. We have previously demonstrated that melanoma is unable to grow in-vivo in conditions of Dnmt3a depletion in a mouse model. In this study, we cultured the Dnmt3a depletion B16 melanoma (Dnmt3a-D) cell line to conduct a comparative analysis of protein expression con-comitant with Dnmt3a depletion in a melanoma cell line. After two-dimensional separation, by gel electro-phoresis and liquid chromatography, combined with mass spectrometry analysis (1DE-LC-MS/MS), the re-sults demonstrated that 467 proteins were up-regulated and 535 proteins were down-regulated in the Dnmt3a-D cell line compared to the negative control (NC) cell line. The Genome Ontology (GO) and KEGG pathway were used to further analyze the altered proteins. KEGG pathway analysis indicated that the MAPK signaling pathway exhibited a greater alteration in proteins, an interesting finding due to the close relation-ship with tumorigenesis. The results strongly suggested that Dnmt3a potentially controls the process of tu-morigenesis through the regulation of the proteins (JNK1, p38α, ERK1, ERK2, and BRAF) involved in tu-mor-related pathways, such as the MAPK signaling pathway and melanoma pathway.

Toll样受体4(TLR4)基因剔除小鼠构建及初步表型分析

目的:利用CRISPR/Cas9技术构建Toll样受体4(TLR4)基因敲除小鼠模型,并观察突变小鼠对革兰氏阴性细菌脂多糖(LPS)刺激响应的变化。方法:针对TLR4基因外显子2设计并合成1对sgRNA片段,与编码Cas9的mRNA混合后通过受精卵显微注射方法,建立TLR4基因敲除小鼠,通过繁育获得基因敲除纯合子小鼠(TLR4-/-小鼠);通过LPS刺激,分析TLR4-/-小鼠对炎症应激的反应情况,并在分子和病理水平上和野生型对照(WT)进行比较。结果:PCR及测序检测表明TLR4基因外显子2在小鼠基因中被成功敲除;给予LPS刺激后,IL1β、IL6、My D88、i NOS及TNFa等炎症因子的表达在野生型小鼠的心、肝和肺组织中显著上调,而在TLR4-/-小鼠中则几乎没有变化;血生化指标显示LPS刺激后WT小鼠血清中的尿素(Urea)和肌酐(Cre)水平显著升高,而TLR4-/-小鼠刺激前后无显著变化,病理分析同样发现TLR4-/-小鼠能够抵抗LPS对肾组织的损伤。结论:利用CRISPR/Cas9技术成功构建了TLR4基因剔除小鼠模型,TLR4的缺失能够降低IL1β、IL6、My D88、i NOS及TNFa炎症因子对LPS刺激的响应,抑制LPS引起的炎症反应及对组织的损伤。

Rdh13 deficiency weakens carbon tetrachloride-induced liver injury by regulating Spotl4 and Cyp2e1 expression levels

Mitochondrion-localized retinol dehydrogenase 13 (Rdh13) is a short-chain dehydrogenase/reductase involved in vitamin A metabolism in both humans and mice. We previously generated Rdh13 knockout mice and showed that Rdh13 deficiency causes severe acute retinal light damage. In this study, considering that Rdh13 is highly expressed in mouse liver, we further evaluated the potential effect of Rdh13 on liver injury induced by carbon tetrachloride (CC14). Although Rdh13 deficiency showed no significant effect on liver histology and physiological functions under regular culture, the Rdh13^-/- mice displayed an attenuated response to CCl4-induced liver injury. Their livers also exhibited less histological changes and contained lower levels of liver-related metabolism enzymes compared with the livers of wild-type (WT) mice. Furthermore, the Rdhl3 1 mice had Rdh13 deficiency and thus their liver cells were protected from apoptosis, and the quantity of their proliferative cells became lower than that in WT after CC14 exposure. The ablation of Rdhl3 gene decreased the expression levels of thyroid hormone-inducible nuclear protein 14 (Spot14) and cytochrome P450 (Cyp2el) in the liver, especially after CC14 treatment for 48 h. These data suggested that the alleviated liver damage induced by CC14 in Rdh13^-/- mice was caused by Cyp2el enzymes, which promoted reductive CC14 metabolism by altering the status of thyroxine metabolism. This result further implicated Rdhl3 as a potential drug target in preventing chemically induced liver injury.

Studies of substrate binding region of mEAAC1 and mASCT1 by constructing chimeras

The cDNA chimeras between two subtypes of mouse excitatory amino acid transporter family, mouse excitatory amino acid carrier 1 （mEAAC1） and mouse alanine serine cysteine transporter 1 （mASCT1）, were constructed by recombinant PCR. After transcription in vitro, the cRNA was injected and expressed in Xenopus laevis oocytes. 3H-Glu and 3H-Ser were used as isotopic tracer to measure the flux of amino acids. The results showed that there might not be the key amino acids responsible for substractive specificity in the NH2-terminal and its adjacent regions of these two transporters, which probably supported the formation of the substrata binding sites.