[A multicenter, double-blind, randomized controlled clinical trial comparing ergometrine with oxytocin and oxytocin alone for prevention of postpartum hemorrhage at cesarean section].

Objective: To compare oxytocin combined with ergometrine with oxytocin alone in terms of primary prophylaxis for postpartum hemorrhage (PPH) at the time of cesarean section (CS). Methods: This was a multicenter double-blind randomized controlled interventional study comparing ergometrine combined with oxytocin and oxytocin alone administered at CS. From December 2018 to November 2019, a total of 298 parturients were enrolled in 16 hospitals nationwide. They were randomly divided into experimental group (ergometrine intra-myometrial injection following oxytocin intravenously; 148 cases) and control group (oxytocin intra-myometrial injection following oxytocin intravenously; 150 cases) according to 1∶1 random allocation. The following indexes were compared between the two groups: (1) main index: blood loss 2 hours (h) after delivery; (2) secondary indicators: postpartum blood loss at 6 h and 24 h, placental retention time, incidence of PPH, the proportion of additional use of uterine contraction drugs, hemostatic drugs or other hemostatic measures at 2 h and 24 h after delivery, the proportion requiring blood transfusion, and the proportion of prolonged hospital stay due to poor uterine involution; (3) safety indicators: nausea, vomiting, dizziness and other adverse reactions, and blood pressure at each time point of administration. Results: (1) The blood loss at 2 h after delivery in the experimental group [(402±18) ml] was less than that in the control group [(505±18) ml], and the difference was statistically significant (P<0.05). (2) The blood loss at 6 h and 24 h after delivery in the experimental group were less than those in the control group, and the differences were statistically significant (all P<0.05). There were no significant differences between the two groups in the incidence of PPH, the proportion of additional use of uterine contraction drugs, hemostatic drugs or other hemostatic measures at 2 h and 24 h after delivery, the proportion requiring blood transfusion, and the proportion of prolonged hospital stay due to poor uterine involution (all P>0.05). (3) Adverse reactions occurred in 2 cases (1.4%, 2/148) in the experimental group and 1 case (0.7%, 1/150) in the control group. There was no significant difference between the two groups (P>0.05). The systolic blood pressure within 2.0 h and diastolic blood pressure within 1.5 h of drug administration in the experimental group were higher than those in the control group, and the differences were statistically significant (P<0.05), but the blood pressure of the two groups were in the normal range. Conclusion: The use of ergometrine injection in CS could reduce the amount of PPH, which is safe and feasible.

Circle RNA FOXP1 promotes cell proliferation in lung cancer by regulating miR-185-5p/Wnt1 signaling pathway.

OBJECTIVE: It is reported that circular RNA plays an important role in various cancers in recent years. However, there is less investigation reported in lung adenocarcinoma (LUAD) about circRNA. This study aims to explore the role and molecular mechanism of circle RNA FOXP1 in LUAD procession. PATIENTS AND METHODS: The levels of circFOXP1 and miR-185-5p in LUAD cell lines and LUAD cancer samples were examined by RT-PCR. The functions of circFOXP1 and miR-185-5p at LUAD cells were detected by cell transfection of the overexpression or repression. The A549 and H1299 cell proliferation were detected by MTT assay and colony formation assay. And the cell apoptosis was detected by TUNEL assay. The expression levels WNT1 were measured by Western blot in A549 and H1299 cells. Furthermore, the luciferase assay detected the direct interaction between circFOXP1 and miR-185-5p or miR-185-5p and WNT1. RESULTS: The circFOXP1 expression was increased in LUAD patients and LUAD cell lines. The downregulation of circFOXP1 significantly repressed LUAD cell proliferation and promoted cell apoptosis. Moreover, the luciferase assay results confirmed that circFOXP1 directly interacted with miR-185-5p. Overexpression of miR-185-5p could reverse the effect of circFOXP1 in LUAD cell. Besides, the luciferase results showed that miR-185-5p directly interacted with WNT1. miR-185-5p overexpression inhibited the WNT1 expression, while circFOXP1 repression decreased the WNT1 level in LUAD cell lines. The downregulating WNT1 could reverse the effects of miR-185-5p inhibition in LUAD cell lines. Furthermore, WNT1 was significantly upregulated in LUAD cancer tissues. In addition, circFOXP1 level was negatively correlated with miR-185-5p expression and positively correlated with WNT1 expression in LUAD cancer tissues. CONCLUSIONS: These data suggested that circFOXP1 promoted cell proliferation and repressed cell apoptosis in LUAD by regulating miR-185-5p/WNT1 signaling pathway. It provides a novel potential therapeutic agent for the treatment of LUAD.

ERα-dependent stimulation of LCN2 in uterine epithelium during mouse early pregnancy.

Maintenance of a suitable uterine milieu is important for embryo development and subsequent implantation during early pregnancy. High estrogen level in proestrous and estrous stages is essential for uterine anti-bacterial activity during preimplantation period. Lipocalin-2 is an essential molecule which prevents bacterial infection by sequestering iron. In this study, the highest expression of lipocalin-2 is observed in the endometrial epithelium on day 1 of normal pregnancy and pseudopregnancy, which exhibit a similar hormone scenario. By injecting the agonists for estrogen receptor α and estrogen receptor ß in ovariectomized mice, we found estrogen receptor α is the dominant member for estrogen regulation on lipocalin-2 expression. Estrogen treatment in estrogen receptor α-knockout mice further confirmed the role of estrogen receptor α. Using published data from whole-genome estrogen receptor α binding site assay, significant estrogen receptor α recruitment peaks are found at the downstream of lipocalin-2 gene after estrogen treatment. Furthermore, to study the anti-bacterial activity of lipocalin-2 in uterus, Escherichia coli is injected to mimic bacterial infection. Our results showed an obvious induction of lipocalin-2 in Escherichia coli-treated group. Taken together, this study indicates estrogen regulation of lipocalin-2 in uterine epithelium is mediated by estrogen receptor α, and lipocalin-2 may have anti-bacterial activity during early pregnancy.

[Meta analysis on HBsAg-positive rate among general populations aged 1-59 years, 2007-2016, China].

Objective: To perform a Meta-analysis on hepatitis B surface antigen (HBsAg)-positive rates among general Chinese population aged 1-59 years. Methods: We systemically reviewed the related data (January 2007 to August 2016) published from Chinese National Knowledge Infrastructure (CNKI), VIP, and PubMed. We also assessed the HBsAg-positive rates among general Chinese populations aged 1-59 years, using a random effects regression model with the comprehensive Meta-analysis software 2.2. Results: A total of 46 papers were finally included, with a total sample size of 625 053 individuals. Results from the Meta-analysis showed that the overall combined HBsAg-positive rate was 5.7% (95%CI: 4.8%-6.6%) among general Chinese populations aged 1-59 years. When comparing the HBsAg-positive rates in different regions, data showed that the HBsAg-positive rate of was higher in the mid-western areas (6.3%, 95%CI: 4.9%-8.0%) than in the eastern areas (5.5%, 95%CI: 4.4%-6.8%). Results showed that HBsAg-positive rates was higher in males (6.1%, 95%CI: 5.3%-7.0%) than in females (4.8%, 95%CI: 4.2%-5.5%). As for the HBsAg-positive rates in different time periods, data showed positive rate of 6.3% (95%CI: 5.5%-7.2%) in 2007-2009, 5.9% (95%CI: 4.4%-8.0%) in 2010-2012 and 3.5% (95%CI: 2.0%-6.1%) in 2013- 2016, respectively. Conclusion: The prevalence of hepatitis B virus infection was decreasing between 2007 and 2016 in China, making the country an intermediate endemic area on HBV.

[An investigation on immunological effect of hepatitis B vaccine amongst adult population in high-labor-export rural regions, under 4 different strategies].

Objective: To grope for an ideal immune strategy in grown-ups via comparison of immunological effects under 4 different vaccination schemes. Methods: Study population was selected by stratified random cluster sampling. A total of 4 different vaccination proposals, including Strategy A (3 doses, 10 µg, administrated repeatedly into the unilateral deltoid muscle at 0-1-6 months), Strategy B (2 doses, 20 µg, administrated into the bilateral deltoid muscles simultaneously), Strategy C (3 doses, 10 µg, administrated repeatedly into the unilateral deltoid muscle at 0-1-2 months) and Strategy D (2 doses, 10 µg, administrated to the bilateral deltoid muscles at the same time), were conducted in Liangzhou, Minqin Gulang, and the Tianzhu Tibetan Autonomic county respectively, in Wuwei city, Gansu province. Under 4 different strategies, post-vaccination immunological effectiveness was evaluated when blood samples of participants collected in the eighth months, post-first injection and in the third year, and tested by enzyme-linked immunoassays and electro-chemiluminescence immunoassay. Chi-squared test and Fisher exact test were used to evaluate the immunological differences between the 4 strategies. Wilcoxon' s signed rank test and Kruskal-Waillis H test were conducted to compare the differences of the geometric mean titers (GMTs) of antibody against HBV surface antigen (anti-HBs) titers. Results: A total of 1 621 eligible participants aged 16 to 60 years old, were recruited for the study. Numbers of administration and gender were testified as the presuming factors for influencing immune effectiveness. The vaccination completion rates were 53.97% and 79.82% in Strategy A and C, respectively, and the difference statistically significant (P<0.05). In the first year, the protective antibody sero-conversion rates (standardization rate) were 89.21%, 54.88%, 92.11%, and 41.63%, in Strategy A, B, C and D, respectively, and the significant statistically differences emerged (P<0.05) if Strategy B, C and D were compared with Strategy A (as the gold standard). Over a 3-year follow-up period, the levels of GMTs on protective antibody declined from 179.2 IU/L, 51.6 IU/L, 277.1 IU/L and 10.1 IU/L to 61.3 IU/L, 21.2 IU/L, 31.8 IU/L and 6.0 IU/L in Strategy A, B, C and D, respectively, and the differences of declination on GMTs showed statistically significant differences (P<0.05) when compared within or between the 4 strategies. Conclusion: The 0-1-2 months' prophylactic schedules (Strategy C) seemed superior to the others, in terms of effectively inducing the protective antibody, with shorter duration of vaccination, persisting longer immunity and having higher rate of completive vaccination, so is worth to be recommended as a feasible immune programme for adults, especially for migrants from the rural regions.

Huntingtin gene CAG repeat numbers in Chinese patients with Huntington's disease and controls.

BACKGROUND AND PURPOSE: Huntington's disease is due to a CAG triplet repeat elongation in the huntingtin gene. Boundaries in CAG numbers have been found between healthy people with and without risk to pass the disorder to the next generation, and between people without, with a mild, or with a fully penetrant phenotype. These data have been generated in western populations and it is not clear whether they are also valid amongst Chinese. METHODS: In order to establish normative data in the huntingtin gene for Chinese people, 966 chromosomes from normal controls were tested. Further, the range of CAG repeats was examined in a cohort from six centres and a total of 368 patients with the disease were included. RESULTS: The CAG triplet repeat range in normal controls was between 9 and 35 (mean 18.9, SD 2.57). Triplets in the range between 26 and 35 were found in 2.5%. In the patient cohort, triplet repeats in the shorter allele were between 8 and 37 (mean 17.7, SD 1.6). In the longer allele, a range between 36 and 120 was found. There was a negative correlation (-0.65, r = 0.42) between age at onset and the number of triplet repeats in the larger allele. The mean age at onset was 38 years, with a range between 2 and 70 years. In 23 patients (6%) a childhood or juvenile onset was noted. CONCLUSION: These data show comparable ranges of huntingtin gene CAG triplet repeats in normal people and in patients with Huntington's disease as in western populations.

Identification of inhibitors of bacterial transcription/translation machinery utilizing a miniaturized 1536-well format screen.

This report presents the miniaturization of a HTS screen to identify inhibitors of prokaryotic transcription-translation in a 1536-well format. The in vitro assay design utilized the bacterial expression machinery to drive expression of a firefly luciferase reporter gene, which was read as an endpoint luminesence measurement. This multicomponent system permits identification of inhibitors at different steps in this pathway. Successful miniaturization required integration of homogeneous assay formats, robust liquid-handling workstations, and second-generation imaging systems. Comparison of data from a triplicate 1536-well screen of a subset of a target library that had been previously validated and followed up for hit confirmation in a 384-well plate format confirmed that triplicate screening yields data of higher confidence and quality, eliminates the time-consuming and potentially error-prone step of cherry-picking, and reduces the number of false positives and negatives. The substantial savings of reagents and reduction of the numbers of plates to process obtained in a 1536-well format as compared to a 384-well format allowed a full triplicate evaluation of the entire library of 183,000 compounds at lower cost and in less time. The triplicate-screen statistics are consistent with a highly reliable data set with a coefficient of variation of 14.8% and Z' and Z values of 0.57 and 0.25, respectively. This screen resulted in the identification of 1,149 hits (0.63% hit rate), representing a compound population at 2.5 standard deviations from the mean cutoff. Furthermore, the data demonstrate good agreement between IC(50) values derived for this assay in a 1536-well format and 384-well format.

Role of placental tissues in the intrauterine transmission of hepatitis B virus.

OBJECTIVE: The purpose of this study was to determine the mechanism of intrauterine transmission of hepatitis B virus. STUDY DESIGN: Placental tissues from 158 pregnant women who tested positive for hepatitis B surface antigen were examined for hepatitis B virus markers, Fc gamma receptors, and hepatitis B surface antigen-anti-hepatitis B surface antigen in different layers of cells. RESULTS: It was shown that the hepatitis B virus infection rate among different layers of placental cells gradually decreased from the maternal side to the fetal side. Furthermore, the closer the infected cell layer was to the fetal side, the higher the risk of intrauterine hepatitis B virus infection. Fc gamma receptors were found on cells of both hepatitis B surface antigen positive and negative placentas; Fc gamma receptors III were found on trophoblastic cells and villous mesenchymal cells, and Fc gamma receptors II were found on only villous mesenchymal cells. Hepatitis B surface antigen-antibodies to hepatitis B surface antigen was detected in the cytoplasm and on the membrane of trophoblastic cells and villous mesenchymal cells in 2 hepatitis B surface antigen-positive placentas. CONCLUSION: The results support the hypothesis that intrauterine hepatitis B virus transmission could be caused through "cellular transfer" in the placenta. One of the means of cellular transfer could be through Fc gamma receptor III-mediated entry of hepatitis B surface antigen-antibodies to hepatitis B surface antigen into cells.

Oxazolidinones mechanism of action: inhibition of the first peptide bond formation.

Oxazolidinones are potent inhibitors of bacterial protein biosynthesis. Previous studies have demonstrated that this new class of antimicrobial agent blocks translation by inhibiting initiation complex formation, while post-initiation translation by polysomes and poly(U)-dependent translation is not a target for these compounds. We found that oxazolidinones inhibit translation of natural mRNA templates but have no significant effect on poly(A)-dependent translation. Here we show that various oxazolidinones inhibit ribosomal peptidyltransferase activity in the simple reaction of 70 S ribosomes using initiator-tRNA or N-protected CCA-Phe as a P-site substrate and puromycin as an A-site substrate. Steady-state kinetic analysis shows that oxazolidinones display a competitive inhibition pattern with respect to both the P-site and A-site substrates. This is consistent with a rapid equilibrium, ordered mechanism of the peptidyltransferase reaction, wherein binding of the A-site substrate can occur only after complex formation between peptidyltransferase and the P-site substrate. We propose that oxazolidinones inhibit bacterial protein biosynthesis by interfering with the binding of initiator fMet-tRNA(i)(Met) to the ribosomal peptidyltransferase P-site, which is vacant only prior to the formation of the first peptide bond.

Detection of elevated serum beta-chemokine levels in seronegative Chinese individuals exposed to human immunodeficiency virus type 1.

The mutations in the CCR5 coding region, such as CCR5Delta32 and CCR5m303, that suppress the transmission of human immunodeficiency virus (HIV) type 1 do not exist in Chinese people. However, 9 Chinese subjects in Taiwan with histories of multiple sexual exposures to HIV remained uninfected, suggesting that certain anti-HIV factors do indeed exist. Experiments were therefore designed to investigate the immune mechanism that protects this cohort against HIV infection. Peripheral blood samples from these 9 subjects and 7 healthy people who had not been exposed to HIV were obtained for the quantitation of the levels for beta-chemokines and interleukin 16 (IL-16) in serum samples or secreted by peripheral blood lymphocytes. Significantly higher serum levels for nearly all 3 beta-chemokines, regulation on activation, normal T cell-expressed and secreted, macrophage inflammatory protein (MIP)-1alpha, and MIP-1beta (P<.05, P<.05, and P=.05, respectively), but not IL-16, were detected in the 9 HIV-uninfected subjects as compared with control subjects. The result suggests that among the host genes and cellular factors thus far identified, beta-chemokines are the major HIV-suppressive factors that protect Chinese people from infection with HIV.

Identification of the epitopes on HCV core protein recognized by HLA-A2 restricted cytotoxic T lymphocytes.

AIM: To identify hepatitis C virus(HCV) core protein epitopes recognized by HLA-A2 restricted cytotoxic T lymphocyte (CTL). METHODS: Utilizing the method of computer prediction followed by a 4h(51)Cr release assay confirmation. RESULTS: The results showed that peripheral blood mononuclear cells (PBMC) obtained from two HLA-A2 positive donors who were infected with HCV could lyse autologous target cells labeled with peptide "ALAHGVRAL (core 150-158)". The rates of specific lysis of the cells from the two donors were 37.5% and 15.8%, respectively. Blocking of the CTL response with anti-CD4 mAb caused no significant decrease of the specific lysis. But blocking of CTL response with anti-CD8 mAb could abolish the lysis. CONCLUSION: The peptide (core 150-158) is the candidate epitope recognized by HLAA2 restricted CTL.

Aminohexanoic hydroxamate is a potent inducer of the differentiation of mouse neuroblastoma cells.

Deoxyhypusine synthase is the key enzyme for modifying a lysine residue to hypusine in the cellular protein eukaryotic initiation factor 5A (eIF-5A). Deletion of the deoxyhypusine synthase or the eIF-5A gene in yeast produces lethal phenotype. Inhibition of deoxyhypusine synthase by 1-guanidino-7-aminoheptane (GC7) suppresses tumor cell growth. Hypusine formation represents one of the most specific polyamine-dependent biochemical reactions. In view of the importance of polyamines in growth regulation and cancer biology, deoxyhypusine synthase has been considered to be a good target for chemotherapeutic drug design. Using GC7 as a prototype we have synthesized and tested three classes of diamine analogs, namely, guanidino-, pyrimidino-, and hydroxamate derivatives, as potential inhibitors for deoxyhypusine synthase. Our study shows that (i) among all the compounds tested, GC7 remained to be the most potent inhibitor for deoxyhypusine synthase; (ii) N,N'-bispyrimidino-1, 9-diaminononane, although a poor inhibitor of deoxyhypusine synthase, was a potent growth inhibitor; and (iii) one of the hydroxamate derivatives, 6-aminohexanoic hydroxamate (HC6), prominently induced the differentiation of mouse neuroblastoma cells at sub-millimolar concentrations. Interestingly, other hydroxamates with different chain length were not nearly as effective as HC6 in inducing neuroblastoma cell differentiation. The effect of HC6 was also unique in that it could induce neurite outgrowth and the expression of neuron-specific genes such as synapsin I and MAP-2 in neuroblastoma cells in the absence of other promoting agents such as cAMP. The effect of HC6 on neuroblastoma cell differentiation was comparable with, or better than that of N(6),O(2)'-dibutyryl cAMP (Bt(2)cAMP), a standard reagent commonly used for inducing the differentiation of mouse and human neuroblastoma cells in culture.

Cutaneous blood vessels in scent pigs.

The purpose of this study was to systematically provide anatomic data for flap research in plastic surgery on the cutaneous blood vessels. Seven scent pigs used in this study were killed anesthetically, and their carotid vessels were intubated and injected with a black liquid rubber. Twenty-four hours later, the integument of the scent pig was removed, and the perforating points of the cutaneous vessels were recorded. The different-sized pieces of integument became transparent. Part of this transparent skin tissue was cut into cross-sectional strips. There were three types of the cutaneous vascular source, the same as in humans. Six division levels of vessels in the skin were identified, which formed five vascular plexuses and two systems (the perforating vessel system and the cutaneous vessel system). There were two sets of vein systems: the concomitant vein and the oscillating vein; the latter can be divided into regular and irregular types. The structures of the perforating vessel system and the cutaneous vessel system were the morphological basis for choosing flaps. Two anatomic points have been emphasized: the preserved vascular plexus in thin flaps (not the subcutaneous vascular network reported previously) and the dependency of vascular structure on its location. Otherwise, this study has also provided two new kinds of flaps used in experimental study: the arterial loop flap and the intermuscular septal perforator flap. Although there were differences as well as similarities in skin vasculature between humans and the scent pig, the scent pig is still suitable for flap research.

Purification, cDNA cloning and function assessment of BmK abT, a unique component from the Old World scorpion species.

A new neurotoxic component named BmK abT was purified from the venom of Chinese scorpion Buthus martensi Karsch. The molecular weight of BmK abT was determined to be 7212 Da on a mass spectrum. The minimum lethal dose of BmK abT was tested to be about 1.5 microg per mouse by intracerebroventricular injection, and the dose induced significant paralysis effect on cockroach was about 5 microg by i.p. injection. The partial amino acid sequence indicated that it was a distinctive polypeptide in the scorpion neurotoxin family. Thereafter, the whole amino acid sequence of mature BmK abT was deduced from cDNA sequence by 5'- and 3'-rapid amplification of cDNA ends. Finally, it was defined to be composed of 63 residues with amidation at the C-terminal residue. By sequence comparison, BmK abT was found to be most similar to Ts VII, a beta-toxin from the New World scorpion. The patch-clamp recording on DRG neurons, unexpectedly, showed this toxin could prolong the action potential and increase the amplitude of the peak Na+ currents, which are the typical characters of alpha-toxin. These results suggested that BmK abT was a new toxic component found in the Old World scorpion species structurally similar to beta-toxins, but functionally similar to alpha-toxins.

Influence of nucleotide polymorphisms in the CCR2 gene and the CCR5 promoter on the expression of cell surface CCR5 and CXCR4.

Polymorphisms in the CCR2 gene (CCR2-64I) and the CCR5 promoter (pCCR5-59029G) have been correlated with slower HIV-1 disease progression. How these polymorphisms influence the rate of AIDS progression has remained unclear. We have therefore investigated whether these nucleotide polymorphisms will reduce the expression levels of surface CCR5 and CXCR4, and thus lead to slower AIDS progression. For this, a cohort of Chinese volunteers in Taiwan was subjected to the determination of CCR2 and pCCR5 genotypes followed by analysis of the surface CCR5 and CXCR4 expression on five cell types derived from peripheral blood mononuclear cells by flow cytometry. Several significant associations were detected between genotypes and expression levels of the proteins. The most important finding was that an increased number of CD4(+) cells expressing CCR5 correlated with pCCR5-59029A homozygosity without the interference of both the CCR2-64 and the CCR5 delta 32 (deleted 32 bp) mutations (P: = 0.0453), which is consistent with the previous data on the association of the genotype to AIDS progression. Since different genetic polymorphisms co-exist in human beings, the rate of AIDS progression as well as the risk of rheumatoid arthritis may be governed by the interplay of the array of nucleotide changes and their affected proteins.

Hydroxyl radical formation in chondrocytes and cartilage as detected by electron paramagnetic resonance spectroscopy using spin trapping reagents.

Chondrocytes have been shown to produce superoxide and hydrogen peroxide, suggesting possible formation of hydroxyl radical in these cells. In this study, we used electron spin resonance/spin trapping technique to detect hydroxyl radicals in chondrocytes. We found that hydroxyl radicals could be detected as alpha-hydroxyethyl spin trapped adduct of 4-pyridyl 1-oxide N-tert-butylnitrone (4-POBN) in chondrocytes stimulated with phorbol 12-myristate 13-acetate in the presence of ferrous ion. The formation of hydroxyl radical appears to be mediated by the transition metal-catalyzed Haber-Weiss reaction since no hydroxyl radical was detected in the absence of exogenous iron. The hydroxyl radical formation was inhibited by catalase but not by superoxide dismutase, suggesting that the hydrogen peroxide is the precursor. Cytokines, IL-1 and TNF enhanced the hydroxyl radical formation in phorbol 12-myristate 13-acetate treated chondrocytes. Interestingly, hydroxyl radical could be detected in unstimulated fresh human and rabbit cartilage tissue pieces in the presence of iron. These results suggest that the formation of hydroxyl radical in cartilage could play a role in cartilage matrix degradation.

Altered expression of glutamate transporter GLAST mRNA in rat brain after photochemically induced focal ischemia.

BACKGROUND: The neurotransmitter glutamate is involved in fast excitatory synaptic transmission in the mammalian brain. Glutamate released from presynaptic terminals must be removed rapidly from the synaptic cleft by high affinity, sodium-dependent glutamate transporters to keep the extracellular glutamate concentration low to protect neuron from glutamate excitotoxicity, which is the major pathological mechanism of brain ischemia. GLAST is one of the identified four subtypes of the glutamate transporter system and has been suggested to play an important role in some pathological conditions. But until recently, very little information existed the concerning relationship between GLAST expression and cerebral ischemia. METHODS: Nonradioactive in situ hybridization was employed to evaluate the changes of glutamate transporter GLAST mRNA expression in rat cerebral cortex and hippocampus following photochemically induced focal cortical ischemia. RESULTS: GLAST mRNA expression in cerebral pyramid cells below the infarcted area did not change at 3 h, significantly decreased at 12 h, recovered to the control level at 24 h, and significantly increased at 72 h following the ischemic lesion. No changes in GLAST mRNA expression were observed in all subfields of the hippocampal complex. CONCLUSIONS: The present findings suggest that the time-course changes of GLAST mRNA expression after ischemia may be correlated with the pathogenesis of photosensitive ischemic brain damage.

Effect of glutamate transporter on neuronal damage induced by photochemical thrombotic brain ischemia.

To study the effects of glutamate transporters on the pathogenesis of brain infarct, pharmacological and histological analyses were carried out on the thrombotic focal ischemic model. Expression of mRNA coding for the glutamate transporter GLAST increased significantly in the penumbra at 72 h following the ischemia. Combined with confocal laser scanning microscopic analysis, double staining showed expression of GLAST mRNA in both neurons and glial cells in the penumbra. L-trans-Pyrrolidine-2,4-dicarboxylate (L-trans-PDC), a glutamate uptake inhibitor, dose-dependently enhanced the volume of the infarct induced by the ischemia. The results suggest that a compensatory increase in the activity of glutamate transporter may accompany pathological changes after ischemic injury.

Interaction of eukaryotic initiation factor 5A with the human immunodeficiency virus type 1 Rev response element RNA and U6 snRNA requires deoxyhypusine or hypusine modification.

Hypusine formation on the eukaryotic initiation factor 5A (eIF-5A) precursor represents a unique posttranslational modification that is ubiquitously present in eukaryotic cells and archaebacteria. Specific inhibition of deoxyhypusine synthase leads to growth arrest and cell death. The precise cellular function of eIF-5A and the physiological significance of hypusine modification are not clear. Although the methionyl-puromycin synthesis has been suggested to be the functional assay for eIF-5A activity in vitro, the role of eIF-5A in protein synthesis has not been established. Recent studies have suggested that eIF-5A may be the cellular target of the human immunodeficiency virus type 1 Rev and human T cell leukemia virus type 1 Rex proteins. Motif analysis suggested that eIF-5A resembles a bimodular RNA-binding protein in that it contains a stretch of basic amino acids clustered at the N-terminal region and a leucine-rich stretch at the C-terminal region. Using Rev target RNA, RRE, as a model, we tested the hypothesis that eIF-5A may be an RNA-binding protein. We found that both deoxyhypusine and hypusine-containing eIF-5A can bind to the 252-nt RRE RNA, as determined by a gel mobility shift assay. In contrast, the unmodified eIF-5A precursor cannot. Deoxyhypusine-containing eIF-5A, but not its precursor, could also cause supershift of the Rev stem-loop IIB RRE complex. Preliminary studies also indicated that eIF-5A can bind to RNA such as U6 snRNA and that deoxyhypusine modification appears to be required for the binding. The ability of eIF-5A to directly interact with RNA suggests that deoxyhypusine formation of eIF-5A may be related to its role in RNA processing and protein synthesis. Our study also suggests the possibility of using a gel mobility shift assay for eIF-5A-RNA binding as a functional assay for deoxyhypusine and hypusine formation.