Microfabrication technology: organized assembly of carbon nanotubes

Nanoscale structures need to be arranged into well-defined configurations in order to build integrated systems. Here we use a chemical-vapour deposition method with gas-phase catalyst delivery to direct the assembly of carbon nanotubes in a variety of predetermined orientations onto silicon/silica substrates, building them into one-, two- and three-dimensional arrangements. The preference of nanotubes to grow selectively on and normal to silica surfaces forces them to inherit the lithographically machined template topography of their substrates, allowing the sites of nucleation and the direction of growth to be controlled.

Regulation of SDF-1 (CXCL12) production by osteoblasts; a possible mechanism for stem cell homing

Stromal derived factor-1 (SDF-1 or CXCL12) controls many aspects of stem cell function including trafficking and proliferation. Previously, it was demonstrated that DNA-damaging agents such as irradiation, cyclophosphamide or 5-fluorouracil increase the expression of SDF-1 by osteoblasts in murine marrow. Here, the production of SDF-1 by osteoblasts in vitro in response to cytokines known to be particularly important in bone physiology was examined using primary human osteoblasts (HOBs), mixed marrow stromal cells (BMSCs), and by, mouse, rat and human osteoblast-like cell lines. From these studies, it was determined that the expression of SDF-1 is an early feature of osteoblastic induction that may be modulated by IL-1beta, PDGF-BB, VEGF, TNF-alpha and PTH. Each of these factors increased SDF-1 synthesis, while TGF-beta1 decreased SDF-1 secretion. Of note, the biodistribution of SDF-1 in culture was equally distributed between the medium and detergent-soluble and -insoluble fractions of the cultures. Immunohistochemistry of developing bones demonstrated that SDF-1 was also a feature of early bone development first beginning in the perichondrium and moving into the marrow cavity of the developing bone analogue. As SDF-1 expression increases in response to PTH in vitro, animals were treated with an anabolic regime of PTH for 21 days. Under these conditions, significant increases in SDF-1 mRNA expression were observed near the growth plate and epiphysis regions of the long bones. Yet, in serum, immunodetectable SDF-1 levels were significantly reduced (24%) in the PTH-treated animals (Vehicle: 408 +/- 25 vs. PTH 308 +/- 20 SDF-1 pg/ml). Together, these data suggest a possible mechanism for localizing stem cells into a developing marrow where increased expression of SDF-1 in the local marrow environment along with decreased SDF-1 in the serum may create a homing gradient.

Ethanol diet increases the sensitivity of rats to pancreatitis induced by cholecystokinin octapeptide

BACKGROUND & AIMS

Although alcoholism is a major cause of pancreatitis, the pathogenesis of this disorder remains obscure. Failure to produce experimental alcoholic pancreatitis suggests that ethanol may only increase predisposition to pancreatitis. This study sought to develop a model of ethanol pancreatitis by determining if an ethanol diet sensitizes rats to pancreatitis caused by cholecystokinin octapeptide (CCK-8).

METHODS

Rats were fed intragastrically either control or ethanol diet for 2 or 6 weeks. The animals were then infused for 6 hours with either saline or CCK-8 at a dose of 3000 pmol. kg(-1). h(-1), which by itself did not induce pancreatitis. The following parameters were measured: serum amylase and lipase levels, pancreatic weight, inflammatory infiltration, number of apoptotic acinar cells, pancreatic messenger RNA (mRNA) expression of cytokines and chemokines, and nuclear factor (NF)-kappaB activity.

RESULTS

All measures of pancreatitis, as well as NF-kappaB activity and mRNA expression for tumor necrosis factor alpha, interleukin 6, monocyte chemotactic protein 1, macrophage inflammatory protein 2, and inducible nitric oxide synthase, were significantly increased only in rats treated with ethanol plus CCK-8.

CONCLUSIONS

An ethanol diet sensitizes rats to pancreatitis caused by CCK-8. The combined action of ethanol and CCK-8 results in NF-kappaB activation and up-regulation of proinflammatory cytokines and chemokines in the pancreas. These mechanisms may contribute to the development of alcoholic pancreatitis.

An empirical literature review of definitions of severe and persistent mental illness

Seventeen definitions of the severely and persistently mentally ill have appeared in the literature over the past decade. These definitions have been used by 13 authors to formulate service programs and to estimate the prevalence of serious mental illness in the population. To test the applicability of these definitions, the authors operationalized each definition and applied it to a representative sample of 222 patients receiving services in one of Philadelphia's inner-city neighborhoods. The analysis showed estimates of prevalence of serious mental illness ranging from 4% to 88% of the treated population, depending on the definition applied. The NIMH (1987) definition was representative of the middle-range estimates of 45% to 55% arrived at by eight authors.

Interaction of human Ku70 with TRF2

Ku, a heterodimer of 70- and 80-kDa subunits, plays a general role in the metabolism of DNA ends in eukaryotic cells, including double-strand DNA break repair, V(D)J recombination, and maintenance of telomeres. We have utilized the yeast two-hybrid system to identify Ku70-interacting proteins other than Ku80. Two reactive clones were found to encode the dimerization domain of TRF2, a mammalian telomeric protein that binds to duplex TTAGGG repeats at chromosome ends. This interaction was confirmed using bacterial fusion proteins and co-immunoprecipitations from eukaryotic cells overexpressing TRF2. The transfected TFR2 colocalized with Ku70.

Systematic review with meta-analysis: the efficacy of vonoprazan-based triple therapy on Helicobacter pylori eradication

BACKGROUND

In order to increase eradication rates, vonoprazan, a novel potassium-competitive acid blocker, has been used in Helicobacter pylori eradication therapy.

AIM

To summarise the results of the efficacy of vonoprazan-based triple therapy, helping clinicians to better understand the benefit of vonoprazan in the treatment of H. pylori infection.

METHODS

We conducted a systematic literature search on MEDLINE, EMBASE, and the Cochrane Library using the primary keywords "vonoprazan," "takecab", "TAK-438," "potassium," "competitive," "potassium-competitive," "Helicobacter," and "pylori." Studies were included if they evaluated the eradication rate between the vonoprazan-based and proton pump inhibitor (PPI)-based triple therapies.

RESULTS

Ten studies and 10 644 patients were evaluated. The crude H. pylori eradication rate determined by intention-to-treat analysis was 87.9% and 72.8% in the vonoprazan-based triple therapy and PPI-based triple therapy respectively. The eradication rate of the vonoprazan-based triple therapy was superior to that of the PPI-based triple therapy (pooled risk ratio [RR] [95% confidence interval (CI)]=1.19 [1.15-1.24]) In addition, there was no significant difference in dropout rate due to adverse event between the regimens (pooled RR of the vonoprazan-based triple therapy [95% CI]=0.69 [0.23-2.03]). The incidence of any adverse events also did not differ between the regimens (pooled RR [95% CI]=1.02 [0.78-1.34]).

CONCLUSIONS

The vonoprazan-based triple therapy showed superior efficacy in terms of H. pylori eradication as compared to the PPI-based triple therapy. In addition, the vonoprazan-based triple therapy showed comparable tolerability and incidence of adverse events.

The hedgehog pathway regulates remodelling responses to biliary obstruction in rats

BACKGROUND

Chronic biliary obstruction provokes fibrosis and accumulation of immature ductular cells. This fibroductular reaction resolves following biliary decompression, suggesting that it may also be involved in the repair of biliary damage. The hedgehog (Hh) pathway becomes activated in liver after bile duct ligation (BDL), and might modulate hepatic remodelling because Hh ligands are potent morphogens.

OBJECTIVE

To study the induction of the Hh pathway during progression and resolution of biliary fibrosis, and to clarify whether Hh signalling regulates accumulation of bile duct progenitor cells.

DESIGN AND MAIN OUTCOME MEASURES

Livers from rats with BDL were examined by quantitative real-time polymerase chain reaction analysis and immunohistochemistry to identify factors that might stimulate Hh signalling. BDL rats were subjected to Roux-en-Y hepaticojejunostomy (R-Y) to relieve biliary obstruction in order to determine whether these factors and Hh signalling declined as ductular populations and concomitant fibrosis regressed. Cultures of immature ductular cells were treated with putative Hh inducers and Hh ligands to confirm their functional relevance.

RESULTS

BDL increased expression of platelet-derived growth factor-BB (PDGF-BB) and sonic hedgehog (Shh), downregulated hedgehog-interacting protein (Hip), activated Hh signalling, and expanded populations of Hh-responsive ductular cells that expressed pancyotkeratin, a liver progenitor cell marker. After R-Y, Hip remained suppressed, expression of PDGF-BB and Shh gradually declined, and populations of hedgehog-responsive ductular cells regressed. In cultured ductular cells, PDGF-BB treatment induced Shh expression, and incubation with Shh inhibited apoptotic activity.

CONCLUSIONS

These results identify a mechanism for activation of the Hh pathway during cholestasis and suggest that Hh signalling regulates ductular cell accumulation after biliary injury.

Suppression of interleukin-1 beta-converting enzyme-mediated cell death by insulin-like growth factor

COS cells are resistant to cell death induced either by interleukin-1beta-converting enzyme (*ICE) and ICE homolog (ICH-1L) overexpression or by serum deprivation. COS cells deprived of serum undergo apoptosis after transfection with an ICE expression construct, but not an ICH-1L construct. ICE-mediated apoptosis of COS cells in serum-free medium is suppressed by insulin-like growth factor (IGF)-1 and insulin. Viability of Rat-1 cell line (Rat-1/ICE) expressing low levels of ICE-LacZ fusion protein is lower than those of cell lines expressing either both Bcl-2 and ICE or mutant ICEGly-->Ser during serum deprivation. Enzymatic activation and processing of ICE are observed in cells induced to die by serum deprivation, which are suppressed by IGF-1. IGF-1 or insulin suppresses ICE-mediated cell death without affecting the expression levels of Bcl-2, Bcl-x, or Bax. Taken together, these results indicate that ICE is activated by growth factor deprivation, and IGF-1 is able to suppress ICE-mediated cell death through a mechanism independent of the expression of Bcl-2, Bcl-x, or Bax.

Identification of six novel MYH9 mutations and genotype-phenotype relationships in autosomal dominant macrothrombocytopenia with leukocyte inclusions

The autosomal dominant macrothrombocytopenia with leukocyte inclusions, May-Hegglin anomaly (MHA), Sebastian syndrome (SBS), and Fechtner syndrome (FTNS), are rare platelet disorders characterized by a triad of giant platelets, thrombocytopenia, and characteristic Döhle body-like leukocyte inclusions. The locus for these disorders was previously mapped on chromosome 22q12.3-q13.2 and the disease gene was recently identified as MYH9, the gene encoding the nonmuscle myosin heavy chain-A. To elucidate the spectrum of MYH9 mutations responsible for the disorders and to investigate genotypephenotype correlation, we examined MYH9 mutations in an additional 11 families and 3 sporadic patients with the disorders from Japan. Korea, and China. All 14 patients had heterozygous MYH9 mutations, including three known mutations and six novel mutations (three missense and three deletion mutations). Two cases had Alport manifestations including deafness, nephritis, and cataracts and had R1165C and E1841K mutations, respectively. However, taken together with three previous reports, including ours, the data do not show clear phenotype-genotype relationships. Thus, MHA, SBS, and FTNS appear to represent a class of allelic disorders with variable phenotypic diversity.

Thulium-doped fiber amplifier for optical communications at 2 µm

We report the first experimental realization and detailed characterization of thulium doped fiber amplifiers (TDFAs) specifically designed for optical communications providing high gain (>35 dB), noise figure as low as 5 dB, and over 100 nm wide bandwidth around 2 µm. A maximum saturated output power of 1.2 W was achieved with a slope efficiency of 50%. The gain dynamics of the amplifier were also examined. Our results show that TDFAs are well qualified as high performance amplifiers for possible future telecommunication networks operating around 2 µm.

Extracellular zinc activates p70 S6 kinase through the phosphatidylinositol 3-kinase signaling pathway

We have studied a possible role of extracellular zinc ion in the activation of p70S6k, which plays an important role in the progression of cells from the G(1) to S phase of the cell cycle. Treatment of Swiss 3T3 cells with zinc sulfate led to the activation and phosphorylation of p70S6k in a dose-dependent manner. The activation of p70S6k by zinc treatment was biphasic, the early phase being at 30 min followed by the late phase at 120 min. The zinc-induced activation of p70S6k was partially inhibited by down-regulation of phorbol 12-myristate 13-acetate-responsive protein kinase C (PKC) by chronic treatment with phorbol 12-myristate 13-acetate, but this was not significant. Moreover, Go6976, a specific calcium-dependent PKC inhibitor, did not significantly inhibit the activation of p70S6k by zinc. These results demonstrate that the zinc-induced activation of p70S6k is not related to PKC. Also, extracellular calcium was not involved in the activation of p70S6k by zinc. Further characterization of the zinc-induced activation of p70S6k using specific inhibitors of the p70S6k signaling pathway, namely rapamycin, wortmannin, and LY294002, showed that zinc acted upstream of mTOR/FRAP/RAFT and phosphatidylinositol 3-kinase (PI3K), because these inhibitors caused the inhibition of zinc-induced p70S6k activity. In addition, Akt, the upstream component of p70S6k, was activated by zinc in a biphasic manner, as was p70S6k. Moreover, dominant interfering alleles of Akt and PDK1 blocked the zinc-induced activation of p70S6k, whereas the lipid kinase activity of PI3K was potently activated by zinc. Taken together, our data suggest that zinc activates p70S6k through the PI3K signaling pathway.

Near-IR absorbance changes and electrogenic reactions in the microsecond-to-second time domain in Photosystem I

The back-reaction kinetics in Photosystem I (PS I) were studied on the microsecond-to-s time scale in cyanobacterial preparations, which differed in the number of iron-sulfur clusters to assess the contributions of particular components to the reduction of P700+. In membrane fragments and in trimeric P700-FA/FB complexes, the major contribution to the absorbance change at 820 nm (delta A820) was the back-reaction of FA- and/or FB- with lifetimes of approximately 10 and 80 ms (approximately 10% and 40% relative amplitude). The decay of photoinduced electric potential (delta psi) across a membrane with directionally incorporated P700-FA/FB complexes had similar kinetics. HgCl2-treated PS I complexes, which contain FA but no FB, retain both of these kinetic components, indicating that neither can be assigned uniquely to a specific acceptor. These results suggest that FA- reduces P700+ directly and argue for a rapid electron equilibration between FA and FB, which would eliminate their kinetic distinction in a back-reaction. In PsaC-depleted P700-Fx cores, as well as in P700-FA/FB complexes with chemically reduced FA and FB, the major contribution to the delta A820 and the delta psi decay is a biphasic back-reaction of F-X (approximately 400 microseconds and 1.5 ms) with some contribution from A-1 (approximately 10 microseconds and 100 microseconds), the latter of which is variable depending on experimental conditions. The delta A820 decay in a P700-A1 core devoid of all iron-sulfur clusters comprises two phases with lifetimes of 10 microseconds and 130 microseconds (2.7:1 ratio). The biexponential back-reaction kinetics found for each of the electron acceptors may be related to existence of different conformational states of the PS I complex. In all preparations studied, excitation at 532 nm with flash energies exceeding 10 mJ gives rise to formation of antenna 3Chl, which also contributes to delta A820 decay on the tens-of-microsecond time scale. A distinction between delta A820 components related to back-reactions and to 3Chl decay can be made by analysis of flash saturation dependencies and by measurements of kinetics with preoxidized P700.

Identification of the calcium binding sites in translationally controlled tumor protein

Translationally controlled tumor protein (TCTP), also known as IgE-dependent histamine-releasing factor, is a growth-related tumor protein. Although the primary sequence of rat TCTP does not reveal any recognizable Ca2+ -binding motif, previous studies have demonstrated that rat TCTP consisting of 172 amino acids is a Ca2+ -binding protein. However, the region of TCTP required for Ca2+ interaction has not been mapped to the molecule. Here, we reported that the Ca2+ binding region of TCTP, which was mapped by using a combination of deletion constructs of rat TCTP and 45Ca2+ -overlay assay, was confined to amino acid residues 81-112. This binding domain did not show any peculiar loop of calcium-binding motif such as CaLB domain and EF hand motif and it seems to be constituted of random coil regions neighboring the a helix. Thus, our data confirm that TCTP is a novel family of Ca2+ -binding protein.

Oxidative DNA damage and cytotoxicity induced by copper-stimulated redox cycling of salsolinol, a neurotoxic tetrahydroisoquinoline alkaloid

A series of neurotoxic tetrahydroisoquinoline alkaloids has been detected in certain regions of mammalian brains. One such dopaminergic tetrahydroisoquinoline neurotoxin is salsolinol (SAL), which is suspected of being associated with the etiology of Parkinson's disease and neuropathology of chronic alcoholism. In the present study, we found that SAL in combination with Cu(II) induced strand scission in pBR322 and phiX174 supercoiled DNA, which was inhibited by the copper chelator, reactive oxygen species (ROS) scavengers, reduced glutathione, and catalase. SAL in the presence of Cu(II) caused hydroxylation of salicylic acid to produce 2,3- and 2,5-dihydroxybenzoic acids. Reaction of calf thymus DNA with SAL plus Cu(II) resulted in substantial oxidative DNA damage as determined by 8-hydroxydeoxyguanosine (8-OH-dG) formation. Blockade of the dihydroxy functional group of SAL abolished its capability to yield 8-OH-dG in the presence of Cu(II). The dehydro analog of SAL, 1-methyl-6,7-dihydroxy-3,4-dihydroisoquinoline, produced significantly high levels of 8-OH-dG when incubated with calf thymus DNA, even in the absence of Cu(II), which appears to be attributable to the tautomer formation by this compound. In another experiment, SAL exerted cytotoxicity when treated to rat pheochromocytoma (PC12) cells. Based on these findings, it seems likely that SAL undergoes redox cycling in the presence of Cu(II) with concomitant production of ROS, particularly hydroxyl radical, which could contribute to DNA damaging and cytotoxic properties of this neurotoxin.

Role of CK1 in GSK3beta-mediated phosphorylation and degradation of snail

The epithelial to mesenchymal transition (EMT) that occurs during embryonic development has begun to attract attention as a potential mechanism for tumor cell metastasis. Snail is a well-known Zn-finger transcription factor that promotes EMT by repressing E-cadherin expression. It is known that Snail is phosphorylated by GSK3beta and degraded by beta-TrCP-mediated ubiquitination. Here we described another protein kinase, CK1, whose phosphorylation of Snail is required for the subsequent GSK3beta phosphorylation. Specific inhibition or depletion of CK1varepsilon inhibits the phosphorylation and degradation of Snail and promotes cell migration, suggesting a central role of CK1varepsilon in the EMT process. Furthermore, our study uncovered distinct roles and steps of Snail phosphorylation by CK1varepsilon and GSK3beta. Taken together, we identified CK1varepsilon as a new component of the Snail-mediated EMT process, providing insight into the mechanism of human cancer metastasis.

Human Ku70 interacts with heterochromatin protein 1alpha

Ku is involved in the metabolism of DNA ends, DNA repair, and the maintenance of telomeres. It consists of a heterodimer of 70- and 80-kDa subunits. Recently we have demonstrated that Ku70 interacted with TRF2, a mammalian telomere-binding protein. Using the same yeast two-hybrid screening system, we now show that Ku70 also interacts with heterochromatin protein 1alpha (HP1alpha), a protein known to be associated with telomeres as well as heterochromatin. HP1 is a suppressor of the position effect variegation in Drosophila and acts as a transcriptional suppressor in mammalian cells. The interaction with Ku70 in the two-hybrid system was confirmed by a glutathione S-transferase pull-down study using bacterial recombinant proteins in vitro. The interaction was also reproduced in vivo in HeLa cells, where endogenous Ku70 coimmunoprecipitated with HP1alpha. This interaction was more effective in acidic pH and weakened considerably as the pH of the reaction buffer was elevated up to 7.5. Ku80 did not interact with HP1alpha directly. The interaction domains of Ku70 and HP1alpha included the Leu-Ser repeat (amino acids 200-385) and the chromo shadow domain, respectively. Ku70 was largely colocalized with transfected HP1alpha but not with a C-terminal deletion mutant, HP1alpha(Delta)C. In contrast to HP1alpha, Ku70 did not repress transcriptional activity of the reporter gene when tethered to DNA after transfection to mammalian cells. The implication of this interaction is discussed.

The role of sialomucin CD164 (MGC-24v or endolyn) in prostate cancer metastasis

BACKGROUND

The chemokine stromal derived factor-1 (SDF-1 or CXCL12) and its receptor CXCR4 have been demonstrated to be crucial for the homing of stem cells and prostate cancers to the marrow. While screening prostate cancers for CXCL12-responsive adhesion molecules, we identified CD164 (MGC-24) as a potential regulator of homing. CD164 is known to function as a receptor that regulates stem cell localization to the bone marrow.

RESULTS

Using prostate cancer cell lines, it was demonstrated that CXCL12 induced both the expression of CD164 mRNA and protein. Functional studies demonstrated that blocking CD164 on prostate cancer cell lines reduced the ability of these cells to adhere to human bone marrow endothelial cells, and invade into extracellular matrices. Human tissue microarrays stained for CD164 demonstrated a positive correlation with prostate-specific antigen levels, while its expression was negatively correlated with the expression of androgen receptor.

CONCLUSION

Our findings suggest that CD164 may participate in the localization of prostate cancer cells to the marrow and is further evidence that tumor metastasis and hematopoietic stem cell trafficking may involve similar processes.

Effect of endoscopic sinus surgery on asthmatic patients with chronic rhinosinusitis

There have been several reports on the effectiveness of endoscopic sinus surgery (ESS) in asthmatic patients with chronic rhinosinusitis. Whether ESS has a positive effect on the clinical course of asthma still remains controversial. There have been several subjective evaluations but few objective results. We performed a study to evaluate the effectiveness of ESS in 19 patients with asthma who underwent ESS for rhinosinusitis. The use of antiasthma medication and postoperative asthma symptoms was analyzed. Objective changes of pulmonary function tests were evaluated. There was a significant improvement in diurnal and nocturnal asthma symptoms. Improvements in asthma medication scores were also confirmed, and individual asthma symptoms (dyspnea, cough, wheezing, and sputum production) improved significantly. Despite a reduction in use of antiasthma medication after ESS, the parameters of the pulmonary function tests did not change. Both subjectively and objectively, it seems that ESS, when used to treat asthmatic patients with chronic rhinosinusitis, can play a significant role in the clinical improvement of asthma.

Diode-pumped wideband thulium-doped fiber amplifiers for optical communications in the 1800 - 2050 nm window

We present the first in-band diode-pumped TDFAs operating in the 2 µm wavelength region and test their suitability as high performance amplifiers in potential future telecommunication networks. We demonstrate amplification over a 240 nm wide window in the range 1810 - 2050 nm with up to 36 dB gain and noise figure as low as 4.5 dB.

PsaC subunit of photosystem I is oriented with iron-sulfur cluster F(B) as the immediate electron donor to ferredoxin and flavodoxin

The PsaC subunit of photosystem I (PS I) binds two [4Fe-4S] clusters, F(A) and F(B), functioning as electron carriers between F(X) and soluble ferredoxin. To resolve the issue whether F(A) or F(B) is proximal to F(X), we used single-turnover flashes to promote step-by-step electron transfer between electron carriers in control (both F(A) and F(B) present) and HgCl2-treated (F(B)-less) PS I complexes from Synechococcus sp. PCC 6301 and analyzed the kinetics of P700+ reduction by monitoring the absorbance changes at 832 nm in the presence of a fast electron donor (phenazine methosulfate (PMS)). In control PS I complexes exogenously added ferredoxin, or flavodoxin could be photoreduced on each flash, thus allowing P700+ to be reduced from PMS. In F(B)-less complexes, both in the presence and in the absence of ferredoxin or flavodoxin, P700+ was reduced from PMS only on the first flash and was reduced from F(X)- on the following flashes, indicating lack of electron transfer to ferredoxin or flavodoxin. In the F(B)-less complexes, a normal level of P700 photooxidation was detected accompanied by a high yield of charge recombination between P700+ and F(A)- in the presence of a slow donor, 2,6-dichlorophenol-indophenol. This recombination remained the only pathway of F(A)- reoxidation in the presence of added ferredoxin, consistent with the lack of forward electron transfer. F(A)- could be reoxidized by methyl viologen in F(B)-less PS I complexes, although at a concentration two orders of magnitude higher than is required in wild-type PS I complexes, thus implying the presence of a diffusion barrier. The inhibition of electron transfer to ferredoxin and flavodoxin was completely reversed after reconstituting the F(B) cluster. Using rate versus distance estimates for electron transfer rates from F(X) to ferredoxin for two possible orientations of PsaC, we conclude that the kinetic data are best compatible with PsaC being oriented with F(A) as the cluster proximal to F(X) and F(B) as the distal cluster that donates electrons to ferredoxin.

Enhanced wound healing using a 3D printed VEGF-mimicking peptide incorporated hydrogel patch in a pig model

There is a need for effective wound healing through rapid wound closure, reduction of scar formation, and acceleration of angiogenesis. Hydrogel is widely used in tissue engineering, but it is not an ideal solution because of its low vascularization capability and poor mechanical properties. In this study, gelatin methacrylate (GelMA) was tested as a viable option with tunable physical properties. GelMA hydrogel incorporating a vascular endothelial growth factor (VEGF) mimicking peptide was successfully printed using a three-dimensional (3D) bio-printer owing to the shear-thinning properties of hydrogel inks. The 3D structure of the hydrogel patch had high porosity and water absorption properties. Furthermore, the bioactive characterization was confirmed by cell culture with mouse fibroblasts cell lines (NIH 3T3) and human umbilical vein endothelial cells. VEGF peptide, which is slowly released from hydrogel patches, can promote cell viability, proliferation, and tubular structure formation. In addition, a pig skin wound model was used to evaluate the wound-healing efficacy of GelMA-VEGF hydrogel patches; the results suggest that the GelMA-VEGF hydrogel patch can be used for wound dressing.

Apoptosis-linked gene 2 binds to the death domain of Fas and dissociates from Fas during Fas-mediated apoptosis in Jurkat cells

Apoptosis-linked gene 2 (ALG-2) is a member of the family of Ca(2+)-binding proteins with penta-EF-hand and is essential for the execution of apoptosis by various signals including Fas activation. We studied the regulation of ALG-2 during Fas-mediated apoptosis in Jurkat cells. The 22-kDa ALG-2 protein is cleaved and becomes a 19-kDa protein after Fas activation. The appearance of 19-kDa ALG-2 protein increases for 4 h after treatment with 200 ng/ml of anti-Fas Ab treatment and gradually degrades afterward. Confocal microscopic analysis showed that ALG-2 translocated from the plasma membrane to the cytosol during Fas-mediated apoptosis. Therefore, we examined if ALG-2 interacts with Fas. The protein-protein interaction of ALG-2 with Fas was demonstrated using yeast two-hybrid assays as well as in vitro GST pull-down assay. Endogenous ALG-2 was immunoprecipitated with anti-Fas Ab in Jurkat cells without Fas activation. However, the endogenous ALG-2 was no longer immunoprecipitated with anti-Fas Ab 2 h after anti-Fas Ab treatment. This study, for the first time, presents a direct molecular connection of ALG-2 to apoptosis by its direct interaction with Fas, and enlists ALG-2 as a new member of posttranslationally modified proteins during Fas-mediated apoptotic process.

Survival of multidrug-resistant Salmonella typhimurium DT104 in egg powders as affected by water activity and temperature

A study was done to determine if a four-strain mixture of multidrug-resistant Salmonella typhimurium definitive type 104 (DT104) cells and a four-strain mixture of S. typhimurium non-DT104 cells differed in ability to survive in whole egg powder, whole egg powder supplemented with corn syrup solids (38%) and salt (1.9%), egg yolk powder, and egg white powder as affected by a(w)(0.29-0.37 and 0.51-0.61) during storage at 13 or 37 degrees C for 8 weeks. Rates of inactivation of S. typhimurium DT104 and non-DT104 cells were similar within each set of test parameters. With the exception of whole egg powder supplemented with corn syrup solids and salt, death was enhanced at a(w) 0.29-0.37 compared to a(w) 0.51-0.61 when powders were stored at 13 degrees C. Survival of cells in whole egg powder supplemented with corn syrup solids and salt was significantly (P < or = 0.05) higher compared to survival in other egg powders stored at 13 degrees C. The opposite trend occurred in powders at a(w) 0.5-0.61 stored at 37 degrees C. Survival of S. typhimurium DT104 and non-DT104 cells at initial populations of 5.01-5.39 log10 cfu/g of egg white powder containing 4.9, 6.1, or 8.2% moisture at 54 or 82 degrees C for 7 days or 8 h, respectively, was determined. Rates of inactivation of DT104 and non-DT104 cells did not differ. Both cell types were detected in egg white powder containing 4.9% moisture but not in powder containing 8.2% moisture when held at 54 degrees C for 7 days. Heating at 82 degrees C for 8 h failed to eliminate 5 log10 S. typhimurium per g of egg white powder, regardless of the moisture content.

Absence of PsaC subunit allows assembly of photosystem I core but prevents the binding of PsaD and PsaE in Synechocystis sp. PCC6803

In photosystem I (PSI) of oxygenic photosynthetic organisms the psaC polypeptide, encoded by the psaC gene, provides the ligands for two [4Fe-4S] clusters, FA and FB. Unlike other cyanobacteria, two different psaC genes have been reported in the cyanobacterium Synechocystis 6803, one (copy 1) with a deduced amino acid sequence identical to that of tobacco and another (copy 2) with a deduced amino acid sequence similar to those reported for other cyanobacteria. Insertion of a gene encoding kanamycin resistance into copy 2 resulted in a photosynthesis-deficient strain, CDK25, lacking the PsaC, PsaD and PsaE polypeptides in isolated thylakoid membranes, while the PsaA/PsaB and PsaF subunits were found. Growth of the mutant cells was indistinguishable from that of wild-type cells under light-activated heterotrophic growth (LAHG). A reversible P700+ signal was detected by EPR spectroscopy in the isolated thylakoids during illumination at low temperature. Under these conditions, the EPR signals attributed to FA and FB were absent in the mutant strain, but a reversible Fx signal was present with broad resonances at g = 2.079, 1.903, and 1.784. Addition of PsaC and PsaD proteins to the thylakoids gave rise to resonances at g = 2.046, 1.936, 1.922, and 1.880; these values are characteristic of an interaction-type spectrum of FA- and FB-. In room-temperature optical spectroscopic analysis, addition of PsaC and PsaD to the thylakoids also restored a 30 ms kinetic transient which is characteristic of the P700+ [FA/FB]- backreaction. Expression of copy 1 was not detected in cells grown under LAHG and under mixotrophic conditions. These results demonstrate that copy 2 encodes the PsaC polypeptide in PSI in Synechocystis 6803, while copy 1 is not involved in PSI; that the PsaC polypeptide is necessary for stable assembly of PsaD and PsaE into PSI complex in vivo; and that PsaC, PsaD and PsaE are not needed for assembly of PsaA-PsaB dimer and electron transport from P700 to Fx.