A comparison of CFU-GM, BFU-E and endothelial progenitor cells using ex vivo expansion of selected cord blood CD133+ and CD34+ cells

BACKGROUND

CD133 is a newly developed hematopoietic stem cell marker but little is known about its function. Whether CD133(+) cell selection provides any advantage over CD34(+) selection for hematopoietic stem cell isolation and transplantation is unclear. The present study compared colony formation and endothelial cell differentiation of these two cell types from umbilical cord blood (UCB).

METHODS

Mononuclear cells from the same UCB samples were used for both CD133(+) and CD34(+) cell selection. Cells with 97.1% purity were incubated in semi-solid culture medium containing stem cell growth factor (SCGF) and G-CSF or erythropoietin (EPO). Purified cells were also cultured in M199 containing vascular endothelial growth factor (VEGF), basic fibroblast growth factor (bFGF), and insulin-like growth factor-1 (IGF-1).

RESULTS

CD34(+) and CD133(+) cells produced similar numbers of CFU-GM colonies (median 43.25 and 30.5, respectively; P>0.2). However, a greater than four-fold difference in BFU-E colony formation was observed from CD34(+) cells compared with CD133(+) cells (median 35 and 8, respectively; P<0.04). CD34(+) cells gave rise to endothelial-like cells when stimulated with VEGF, bFGF and IGF-1. CD133(+) cells were unable produce this cell type under the same conditions.

DISCUSSION

CD133(+) cells produced smaller BFU-E colonies and were unable to differentiate into mature endothelial cells. CD34(+) cells contained endothelial progenitors that could differentiate into mature cells of this lineage. Based on these data, it appears that CD133 offers no distinct advantage over CD34 as a selective marker for immunoaffinity-based isolation of hematopoietic stem cells and endothelial progenitor cells.

Structure-activity relationship studies on ADAM protein-integrin interactions

The ADAM (a disintegrin and metalloprotease) family of proteins possess multi-domain structures composed of a signal peptide, a prodomain, a metalloprotease domain, a disintegrin-like domain, a cysteine rich domain, an epidermal growth factor-like domain, a transmembrane domain and cytoplasmic tail. The disintegrin-like domain shares sequence similarity with the soluble venom disintegrins, a family of proteins which are potent inhibitors of integrin-mediated platelet aggregation and cell adhesion. Several ADAMs have been reported to interact with integrins, and the disintegrin-like domain may be crucial part in this respect. A description of structure-activity relationship of ADAM proteins interacting with integrin is outlined in this review. The review highlights recent reports on potential integrin family for ADAMs and how ADAMs selectively modulate interaction for integrin mediated cell function. Lastly, it describes progress in understanding the structural features and functional roles of the ADAMs in normal and pathological conditions and how this insight may assist the development of new therapeutic approaches.

Selective depletion of activated T cells by recombinant immunotoxin containing anti-CTLA-4 single-chain fragment of variable antibody and N-terminal fragment of perforin

We constructed a novel immunotoxin, hS83P34, by fusing the fragment containing the N-terminal 34 amino acids of human perforin to the C-terminal of humanized anti-CTLA-4 single chain fragment of variable antibody. In vitro cytotoxicity assays demonstrated that CTLA-4-positive activated human T cells and 6T-CEM were sensitive to hS83P34, while CTLA-4-negative resting T cells and endothelial cell ECV-304 were resistant to hS83P34. The IC50s of hS83P34 for activated T cells and 6T-CEM were about 0.2 micromol/L and 1.0 micromol/L, there was no obvious cytotoxicity of ECV-304 as detected at 8 micromol/L of hS83P34. In tumor graft rejection models, after treatment with 1.2 mg/kg immunotoxin every day for 12 days, the transplanted tumor cells were rescued by immunotoxin. The tumor weights of grafts of the rejection control group, nonrejection control group, and test group were 0.006 +/- 0.014 g, 0.261 +/- 0.048 g, and 0.135 +/- 0.056 g, respectively. In the early 3 days posttransplantation, there were a lot of CD4- and CD8-positive T cells infiltrating into the tumor grafts of the rejection control group, while only a few T cells were detected in the tumor grafts of the test group. According to these results, we concluded that immunotoxin hS83P34 selectively depleted activated T cells in vitro as well as in vivo in an acute rejection model.

Phenotypic features with p53 alterations related to human papillomavirus and prognostic evaluation in cervical cancer

Cervical cancer is one of the most common tumor affecting women worldwide. Human papillomavirus (HPV) was found to have a causal relationship with cervical cancer and its precursors. The interaction between HPV E6 protein and p53 was identified in in vitro studies. The aim of the study was to evaluate the prevalence of p53 alterations related to HPV infection and the prognostic significance of p53 alterations in cervical cancer. Studies were identified by a MEDLINE search, and all relevant articles were retrieved from 1991 to March 2004. The prevalence of p53 mutations is a rare event in cervical cancer. The correlation between p53 mutations and HPV or prognosis is controversial. Loss of heterozygosity (LOH) of p53 is more commonly found in cervical cancer and is related with the prognosis of this disease. There is no significant correlation between p53 polymorphism and development of cervical cancer. The p53 mutations were not commonly found in cervical cancer. LOH of p53 may contribute to the progression of this malignancy. p53 polymorphism failed to be an independent prognostic factor in predicting the outcome of patients with cervical cancer. Further, epidemiologic surveys should be undertaken in larger populations and in different geographical regions.

Reduction of leucocyte telomere length in radiographic hand osteoarthritis: a population-based study

BACKGROUND

Although age is the strongest predictor of osteoarthritis, the exact mechanism underlying this disorder remains elusive.

OBJECTIVE

To examine the association between leucocyte telomere length (LTL), a bio-indicator of ageing, and radiographic hand osteoarthritis.

METHODS

An unselected, predominantly female sample from the TwinsUK Adult Twin Registry (Twin Research and Genetic Epidemiology Unit, St Thomas Hospital, London, UK) was studied. Radiographs of both hands were obtained with a standard posteroanterior view and assessed for radiographic osteoarthritis according to the Kellgren/Lawrence (K/L) score. Individual radiographic features including osteophytes and joint space narrowing (JSN) were also assessed on a four-point scale using a standard atlas. Hand osteoarthritis was defined radiographically as having >or=3 osteoarthritis-affected joints of both hands (K/L score>or=2). Severity of hand osteoarthritis was indicated semiquantitatively by total K/L scores, osteophytes, JSN scores and proportion of joints affected. Mean LTL was measured by the terminal restriction fragment length using the Southern blot.

RESULTS

A total of 1086 Caucasian subjects (mean (SD) age 55 (8.0) years) were studied. LTL was 6.95 (0.64) kb and was inversely correlated with age. After adjustment for age, sex, body mass index and smoking, LTL was significantly shorter by 178 bp in subjects with hand osteoarthritis (n = 160) than in those without (n = 926; p = 0.04). LTL was also significantly associated with semicontinuous measures of osteoarthritis (eg, total K/L score, JSN score, osteophyte score and proportion of joints affected) after adjustment (all p<or=0.02) in a dose-response fashion.

CONCLUSION

Shorter LTL equivalent to around 11 years of annual loss in normal people is associated with radiographic hand osteoarthritis and disease severity, suggesting potential shared mechanisms between osteoarthritis and ageing, and implicating oxidative stress and low-level chronic inflammation in both conditions.

Quantitative structure-property relationship studies on electrochemical degradation of substituted phenols using a support vector machine

A quantitative structure-property relationship (QSPR) model has been developed for the electrochemical degradation of substituted phenols using a support vector machine (SVM). Thirty descriptors, including quantum chemical parameters, steric effect descriptors and half wave potential (E1/2), were used for describing twelve substituted phenols, including mono- and multi-substituent phenols. A leave-one-out (LOO) cross validation procedure resulted in the selection of three descriptors, the total of electron and nuclear energies of the two-center terms for the carbon-chlorine or carbon-nitrogen bond (TE2), the net atomic charges on the chlorine or nitrogen (qx), and the largest negative atomic charge on an atom (q-). The model based on SVM yielded a Q2 value of 0.892, indicating a high predictive ability. Compared with models developed with partial least squares (PLS) and multiple linear regression (MLR), where Q2 were 0.804 and 0.799 respectively, SVM showed higher performances.

Proteomic Analysis of the Genotoxicant Methylazoxymethanol (MAM)-Induced Changes in the Developing Cerebellum

The genotoxicant methylazoxymethanol (MAM) is a widely used developmental neurotoxin, and its glucoside is an etiological factor for western Pacific amyotrophic lateral sclerosis-parkinsonism-dementia complex (ALS/PDC). Identification of global protein expression changes that occur in response to MAM in the developing cerebellum could provide valuable insight into the potential mechanisms involved in the neurodegeneration process. We have utilized fluorescence 2-dimensional differential gel electrophoresis (2D-DIGE), to determine the protein expression changes that occur during normal cerebellar development and in response to MAM. Three day-old postnatal C57BL/6 mice (PND3) received a single injection of MAM, and the cerebella of postnatal day 4 (PND4) and day 22 (PND22) were analyzed. Approximately, 1400 unique spots were matched and quantified in all samples. Comparison of PND4 and PND22 developing cerebellum showed that a significant fraction of the proteome (approximately 68%) changes at this stage. The immediate response of the developing cerebellum to MAM was minimal (approximately 10%). However, significant differences (27%) were noted 14 days after MAM exposure. In contrast, the transcriptome changes were more pronounced at 24 h compared to 14 days. MAM targeted several proteins networks including transport (e.g., alpha-synuclein), cytoskeletal (e.g., beta-tubulin, vimentin), and mitochondrial (e.g., Atp5b) proteins. Immunochemistry confirmed several of the changes in protein expression (alpha-synuclein). Comparison with gene expression changes revealed that the temporal changes observed in the transcriptome and proteome are not correlative. These studies demonstrate for the first time the potential networks involved during neuronal development and neurodegenerative processes that are perturbed by MAM.

Identification of the Critical Role of Tyr-194 in the Catalytic Activity of a Novel N-Acyl-Homoserine Lactonase from Marine Bacillus cereus Strain Y2

Enzymatic disruption of quorum-sensing (QS) pathways in pathogenic organisms is a promising anti-infection therapeutic strategy. AHL-lactonase, a potent tool for biocontrol, can hydrolyze QS signal molecule N-acyl-homoserine lactones (AHLs) into inactive products, thereby blocking the QS systems. A marine bacterial isolate Y2, identified as a Bacillus cereus subsp., was found capable of inactivating AHLs. The aiiA gene encoding the AHL-degrading enzyme from bacterial strain Y2 was cloned and expressed in Escherichia coli. The 28-kDa recombinant Y2-AiiA protein was purified and showed strong AHL-degrading activity. Sequence comparisons of Y2-aiiA with known AHL-lactonases revealed high identities in the deduced amino-acid sequences. Functional determination of a potential catalytic residue Tyr-194 of AHL-lactonases was performed by site-directed mutagenesis. As judged by AHL-degrading bioassay, substitution of Tyr-194 with Ala resulted in a dramatic decrease of activity compared with wild-type (WT) recombinant Y2-AiiA, although the expression level of the mutated Y2-AiiA protein was equivalent to that of WT Y2-AiiA. These results suggested that the conserved residue Tyr-194 is critical for catalytic function of the novel AHL-lactonase.

Long-Term Results of Surgical Treatment of Tetralogy of Fallot in Adults

BACKGROUND

The long-term results of patients with tetralogy of Fallot surgically treated in adulthood were evaluated to define the real benefit of surgical correction.

METHODS

Between August 1990 and February 2004, 57 patients older than 18 years of age with tetralogy of Fallot received total correction. Forty-two patients (73.7 %) required transannular patch.

RESULTS

Hospital and late mortality were 7.0 % (n = 4) and 5.7 % (n = 3), respectively. One patient was reoperated on to close residual ventricular septal defect. Four patients were lost. Of the remaining 49 patients, the mean follow-up was 65 +/- 38 months (range 11 - 173 months). Actuarial survival was 97.4 +/- 2.5 %, 91 +/- 7 % and 72.8 +/- 17.1 % at 5, 10 and 14 years, respectively. At the latest follow-up, 35 (76.1 %) of the surviving patients presently have NYHA functional class I ( P < 0.01).

CONCLUSION

The overall survival of surgically treated adult patients with tetralogy of Fallot is acceptable. The greatest benefit of total correction at this age is the functional improvement.

Integrins in Drug Targeting-RGD Templates in Toxins

Integrins are a family of heterodimeric receptors, which modulate many cellular processes including: growth, death (apoptosis), adhesion, migration, and invasion by activating several signaling pathways. Integrin-binding RGD (arginine-glycine-aspartic acid) is found in several important extracellular matrix proteins which serve as adhesive integrin ligands. The RGD motif has also been found in many toxins from snake venom and other sources that specifically inhibit integrin binding function and serve as potent integrin antagonists, particularly of platelet aggregation and integrin-mediated cell adhesion. Many of these proteins have potential as therapeutic agents which can target integrins directly. Structural and functional studies of several RGD-containing toxins suggest that the inhibitory potency of these proteins lies in subtle positional requirements of the tripeptide RGD at the tip of a flexible loop, a structural feature for binding to integrins. In addition, amino acid residues in this loop in close vicinity to the RGD-motif determine the integrin-binding specificity and selectivity. This review will present a review of integrin structure and function, and of disintegrin structural features responsible for their activity as antagonists of integrin function. The use of integrins in drug targeting and integrins as targets for drug delivery by using the RGD as a template structure will also be discussed.

The tumour-suppressor protein ASPP1 is nuclear in human germ cells and can modulate ratios of CD44 exon V5 spliced isoforms in vivo

The ASPP1 (Apoptosis Stimulating Protein of p53) protein is an important tumour-suppressor. We have detected a novel protein interaction between the human ASPP1 (hASPP1) protein and the predominantly nuclear adaptor protein SAM68. In the human testis, full-length endogenous hASPP1 protein is located in the nucleus like SAM68, predominantly within meiotic and postmeiotic cells. Mouse ASPP1 (mASPP1) protein is mainly expressed in the brain and testis. The interaction with nuclear SAM68 is likely to be restricted to human germ cells, since endogenous mASPP1 protein is exclusively cytoplasmic. The C-terminal region of hASPP1 efficiently targeted a fused GFP molecule to the nucleus, whereas the N-terminus of hASPP1 targeted GFP to the cytoplasm. In the context of the full-length molecule this cytoplasmic targeting sequence is dominant in HEK293 and Saos-2 cells, since full-length hASPP1-GFP is almost exclusively cytoplasmic. Despite its predominantly cytoplasmic location, we show that ASPP1-GFP expression in HEK293 cells can regulate the ratio of alternative spliced isoforms derived from a pre-mRNA regulated downstream of cytoplasmic signalling pathways, and our data suggest that ASPP1 may operate in this case downstream or parallel to RAS signalling pathways.

Frameless Cyberknife radiosurgery for metastatic and primary brain tumors

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Background: Cyberknife delivers image-guided stereotactic radiation to intracranial and extracranial skull base tumors without a frame. This frameless feature makes Cyberknife a completely non-invasive procedure and allows non-surgical neuro-oncology personnel to treat patients with tumors in the neuraxis. Methods: Patients with intracranial tumors were selected from our Brain Tumor Clinic if they were not surgical candidates or had residual tumors after neurosurgery. The decision for Cyberknife radiosurgery was made after careful review of all available treatment options in our multidisciplinary brain tumor conference based on patients’ history and neurologic findings, neuroimaging data, and pathology. All patients signed informed consent prior to fusion head MRI and CT scanning. They were pre-medicated with 4 mg of dexamethasone and 500 mg of levetiracetam twice daily. All dose plans were calculated based on CT images acquired from 1.25-mm slices with an inverse planning technique. Dynamic tracking software monitored patient movements and adjusted the robotic arm accordingly, compensating for patient motion up to 10 mm in translation and 5 degree in rotation. Results: Nine subjects with 15 treatment targets, including 4 meningiomas, 1 high-grade glioma, 1 plasmacytoma, and 3 melanomas, were treated with single-fraction or 5 fractions of Cyberknife radiosurgery. No acute toxicity was seen during or within 24 hours of treatment. One subject developed subacute onset of cerebral edema 2 weeks after the procedure but his symptoms were quickly reversed with dexamethasone. Conclusions: Cyberknife radiosurgery is a well-tolerated procedure for intracranial and extracranial tumors in the skull base. Neuro-oncologist, with the appropriate training, could perform Cyberknife radiation planning with radiation oncologists and physicists.

No significant financial relationships to disclose.

Molecular typing of human adenoviruses by PCR and sequencing of a partial region of the hexon gene

Human adenoviruses (Ads) are responsible for a substantial disease burden. Type-specific identification of Ads can help guide therapeutic and disease prevention strategies and aid epidemiological investigations. Immunotyping of Ads by serum neutralization (SN) is laborious and time consuming and depends upon type-specific antisera that are in short supply. A rapid molecular typing assay based on polymerase chain reaction (PCR) amplification and sequencing of Ad hexon gene hyper-variable regions 1-6 (HVR(1-6)) known to contain type-specific epitopes was evaluated as an alternative to SN. Deduced amino acid sequences of HVR(1-6) obtained from all 51 currently recognized Ad prototype strains were well resolved, with the exception of types 15 and 29, which were identical. Of 192 temporally and geographically diverse Ad field isolates sequenced in this study, and 111 previously published sequences, all more closely matched their predicted prototype strains. Ads were also detected and correctly identified directly from 24 clinical specimens positive by culture or antigen detection. PCR and sequencing of HVR(1-6) offers a practical alternative to SN for typing most Ads and can be readily adapted for use in laboratories with molecular capabilities.

Mediation of endothelial cell damage by serine proteases, but not superoxide, released from antineutrophil cytoplasmic antibody–stimulated neutrophils

OBJECTIVE

To evaluate potential mediators of endothelial cell injury in systemic vasculitis associated with antineutrophil cytoplasmic antibodies (ANCAs), we investigated the factors controlling the neutrophil respiratory burst and endothelial release of von Willebrand factor (vWF) during neutrophil-endothelial cell interactions.

METHODS

Superoxide release from neutrophils binding to purified P-selectin or to tumor necrosis factor-activated endothelial cells was measured under flow or static conditions using the superoxide dismutase (SOD)-inhibitable reduction of ferricytochrome c. Neutrophils were activated with fMLP, normal IgG, or ANCA IgG. Enzyme-linked immunosorbent assay was used to measure vWF. Serine protease activity was measured enzymatically.

RESULTS

ANCA IgG or fMLP induced superoxide release when perfused over neutrophils that were rolling over P-selectin, but not those that were binding to endothelial cells. In static assays, endothelial cells inhibited superoxide production by neutrophils. Adenosine inhibited the respiratory burst, and, in cocultures, adenosine deaminase overcame the inhibitory effects of endothelial cells. Serine proteases were released during activated neutrophil-endothelial cell coculture. There was enhanced release of vWF during activated neutrophil-endothelial cell coculture; this was not inhibited by diphenyleneiodonium or by SOD plus catalase, but was inhibited by diisopropylfluorophosphate.

CONCLUSION

Endothelial cells inhibit superoxide generation by fMLP and ANCA-activated neutrophils. The release of vWF occurs during coculture and is sensitive to serine protease, but not NADPH oxidase inhibition. Serine proteases may play a more important role than reactive oxygen species as mediators of endothelial injury during ANCA-associated systemic vasculitis.

Control of filamentation induced by femtosecond laser pulses propagating in air

Filamentation formed by self-focusing of intense laser pulses propagating in air is investigated. It is found that the position of filamentation can be controlled continuously by changing the laser power and divergence angle of the laser beam. An analytical model for the process is given.

ASPP1 and ASPP2 are new transcriptional targets of E2F

The E2F family of transcription factors regulates the expression of a number of genes whose products are involved in cell cycle control, DNA replication and apoptosis. We show here that E2F-1 binds in vivo the promoters of ASPP1 and ASPP2 genes, two activators of p53-mediated apoptosis, E2F-1, E2F-2 and E2F-3 all activate the isolated ASPP1 and ASPP2 promoters. Overexpression or deregulation of E2F-1 increased the expression levels of ASPP1 and ASPP2 mRNA and proteins. The identification of ASPP1 and ASPP2 genes as transcriptional targets of E2F provides another mechanism by which E2F cooperates with p53 to induce apoptosis.

Role of galanin receptor 1 and galanin receptor 2 activation in synaptic plasticity associated with 3',5'-cyclic AMP response element-binding protein phosphorylation in the dentate gyrus: studies with a galanin receptor 2 agonist and galanin receptor 1 knockout mice

The neuropeptide galanin was shown to impair cognitive performance and reduce hippocampal CA1 long-term potentiation (LTP) in rodents. However, the contribution of the two main galanin receptors; GalR1 and GalR2, present in the hippocampus to these effects is not known. In the present study, we determined the protein expression levels of GalR1 and GalR2 in the mouse dentate gyrus (DG) and used galanin (2-11), a recently introduced GalR2 agonist, and GalR1 knockout mice to examine the contribution of GalR1 and GalR2 to the modulation of LTP and 3',5'-cyclic AMP response element-binding protein (CREB)-dependent signaling cascades. In the DG, 57+/-5% of the galanin binding sites were GalR2, and the remaining population corresponded to GalR1. In hippocampal slices, galanin (2-11) fully blocked the induction of DG LTP, whereas galanin (1-29), a high affinity agonist for both GalR1 and GalR2, strongly but not fully attenuated the late phase of LTP by 80+/-1.5%. Application of galanin (1-29) or galanin (2-11) after LTP induction caused a transient reduction in the maintenance phase of LTP, with the larger effect displayed by superfusion of galanin (2-11). The induction and maintenance of DG LTP was not altered in the GalR1 knockout mice. Superfusion of galanin (1-29) or galanin (2-11) blocked the LTP induction to the same degree indicating a role for GalR2 in the induction phase of DG LTP. Furthermore, we analyzed the effects of GalR1 and/or GalR2 activation on DG LTP-induced CREB phosphorylation, associated with the late transcriptional effects of LTP. In the lateral part of the granule cell layer, high-frequency trains stimulation caused a significant increase in the level of CREB phosphorylation, which was significantly reduced by application of either galanin (1-29) or galanin (2-11), indicating that both GalR1 and/or GalR2 can mediate some of their effects on LTP through inhibition of CREB-related signaling cascades.

Snake Venom Metalloproteinase Containing a Disintegrin-like Domain, its Structure-activity Relationships at Interacting with Integrins

Snake venom disintegrins represent a family of RGD (Arg-Gly-Asp) or KGD (Lys-Gly-Asp)-containing proteins which have been reported to be unique and potentially useful tools not only for investigating integrin-ligand interactions, but also for the development of anti-thrombotic agents in terms of their anti-platelet activities. Snake venom proteins containing a disintegrin-like domain represent another super-family of proteins in which many of them have been demonstrated to have similar ability to inhibit platelet aggregation and integrin-mediated cell adhesion as the disintegrins. This super-family includes a large number of snake venom metalloproteinases and disintegrin related, RGD-containing snake venom proteins (disintegrin-like proteins) such as dendroaspin. Recently, a family of homologues of the snake venom metalloproteinases have been found in a wide variety of mammalian tissues as well as in other eukaryotic organisms termed ADAM (a disintegrin-like and metalloproteinase) proteins. ADAMs are members of the metazincins that also include the related matrix metalloprotease (MMPs). Some of ADAM proteins have now shown to interact with integrins, and the disintegrin-like domain may be crucial part in their function as proteases. A description of structure-activity relationships of snake venom proteins containing a disintegrin-like domain is outlined in this review, along with reports of the modulation of protein activity by recombinant mutation. Comparison is also made of the structural and functional features of the metalloproteinases in snakes compared with those from other species. The review is intended to provide insights in which may assist the development of new therapeutic approaches.