FK506-protective effects against trimethyltin neurotoxicity in rats: hippocampal expression analyses reveal the involvement of periarterial osteopontin

There is little information on the molecular mechanisms in FK506-mediated neuroprotection. In the present study, we investigated the protective effect of FK506, an immunosuppressant and neuroprotectant, on trimethyltin (TMT)-induced neurotoxicity in the rat hippocampus. Histologically, TMT-induced neuronal damage was partially prevented by FK506 in the hippocampal CA1 region, but not in CA3. FK506 treatment significantly reduced the number of apoptotic cells in CA1, but not in CA3, and also prevented induction of cognitive deficits by TMT. Microarray analysis of the rat hippocampus detected 14 genes with TMT-induced alteration of mRNA expression that was rescued by FK506 treatment. Subsequent quantitative RT-PCR analysis confirmed elevated mRNA levels for four inflammatory genes, glutathione S-transferase, lysozyme, matrix Gla protein, and osteopontin after TMT treatment. Upregulation of these genes was reversed by FK506 treatment at 5 days postgavage. Immunohistochemistry revealed that FK506 reduced osteopontin (OPN) induction by TMT in the periarterial area at 5 days postgavage. Our data suggest that inflammatory gene expression is involved in TMT-induced damage to the hippocampal CA1 region, resulting in apoptosis, and that this process is initiated by periarterial OPN activation, and can be alleviated by FK506.

Nanopatterning using NSOM probes integrated with high transmission nanoscale bowtie aperture

Nanoscale ridge aperture antennas have been shown to have high transmission efficiency and confined nanoscale radiation in the near field region compared with regularly-shaped apertures. The radiation enhancement is attributed to the fundamental electric-magnetic field propagating in the TE(10) mode concentrated in the gap between the ridges. This paper reports experimental demonstration of field enhancement using such ridge antenna apertures in a bowtie shape for the manufacture of nanometer size structures using an NSOM (near field scanning optical microscopy) probe integrated with nanoscale bowtie aperture. Consistent lines with width of 59 nm and as small as 24 nm have be written on photoresist using such probes.

Heparanase induces a differential loss of heparan sulphate domains in overt diabetic nephropathy

AIMS/HYPOTHESIS

Recent studies suggest that loss of heparan sulphate in the glomerular basement membrane (GBM) of the kidney with diabetic nephropathy is due to the increased production of heparanase, a heparan sulphate-degrading endoglycosidase. Our present study addresses whether heparan sulphate with different modifications is differentially reduced in the GBM and whether heparanase selectively cleaves heparan sulphate with different domain specificities.

METHODS

The heparan sulphate content of renal biopsies (14 diabetic nephropathy, five normal) were analysed by immunofluorescence staining with four anti-heparan sulphate antibodies: JM403, a monoclonal antibody (mAb) recognising N-unsubstituted glucosamine residues; two phage display-derived single chain antibodies HS4C3 and EW3D10, defining sulphated heparan sulphate domains; and anti-K5 antibody, an mAb recognising unmodified heparan sulphate domains.

RESULTS

We found that modified heparan sulphate domains (JM403, HS4C3 and EW3D10), but not unmodified domains (anti-K5) and agrin core protein were reduced in the GBM of kidneys from patients with diabetic nephropathy, compared with controls. Glomerular heparanase levels were increased in diabetic nephropathy kidneys and inversely correlated with the amounts of modified heparan sulphate domains. Increased heparanase production and loss of JM403 staining in the GBM correlated with the severity of proteinuria. Loss of modified heparan sulphate in the GBM as a result of degradation by heparanase was confirmed by heparan sulphate staining of heparanase-treated normal kidney biopsy specimens.

CONCLUSIONS/INTERPRETATION

Our data suggest that loss of modified heparan sulphate in the GBM is mediated by an increased heparanase presence and may play a role in the pathogenesis of diabetes-induced proteinuria.

An evaluation of impact wrench vibration emissions and test methods

In the interest of providing more effective evaluations of impact wrench vibration exposures and the development of improved methods for measuring vibration emissions produced by these tools, this study focused on three variables: acceleration measured at the tool surface, vibration exposure duration per test trial, and the amount of torque required to unseat the nuts following a test trial. For this evaluation, six experienced male impact wrench operators used three samples each of five impact wrench models (four pneumatic models and one battery-powered model) in a simulated work task. The test setup and procedures were based on those provided by an International Organization for Standardization (ISO) Technical Committee overseeing the revision of ISO 8662-7. The work task involved the seating of 10 nuts onto 10 bolts mounted on steel plates. The results indicate that acceleration magnitudes vary not only by tool type but also by individual tools within a type. Thus, evaluators are cautioned against drawing conclusions based on small numbers of tools and/or tool operators. Appropriate sample sizes are suggested. It was further noted that evaluators could draw different conclusions if tool assessments are based on ISO-weighted acceleration as opposed to unweighted acceleration. As expected, vibration exposure durations varied by tool type and by test subject; duration means varied more for study participants than they did for tool types. For the 12 pneumatic tools evaluated in this study, torque varied directly with tool handle acceleration. Therefore, in order to reduce vibration exposure, tools should be selected and adjusted so that they produce no more than the needed torque for the task at hand.

Differential dopamine receptor D4 allele association with ADHD dependent of proband season of birth

Season of birth (SOB) has been associated with attention deficit hyperactivity disorder (ADHD) in two existing studies. One further study reported an interaction between SOB and genotypes of the dopamine D4 receptor (DRD4) gene. It is important that these findings are further investigated to confirm or refute the findings. In this study, we investigated the SOB association with ADHD in four independent samples collected for molecular genetic studies of ADHD and found a small but significant increase in summer births compared to a large population control dataset. We also observed a significant association with the 7-repeat allele of the DRD4 gene variable number tandem repeat polymorphism in exon three with probands born in the winter season, with no significant differential transmission of this allele between summer and winter seasons. Preferential transmission of the 2-repeat allele to ADHD probands occurred in those who were born during the summer season, but did not surpass significance for association, even though the difference in transmission between the two seasons was nominally significant. However, following adjustment for multiple testing of alleles none of the SOB effects remained significant. We conclude that the DRD4 7-repeat allele is associated with ADHD but there is no association or interaction with SOB for increased risk for ADHD. Our findings suggest that we can refute a possible effect of SOB for ADHD.

MMP2 promoter polymorphism (C-1306T) and risk of recurrence in patients with hepatocellular carcinoma after transplantation

Genetic variants in matrix metalloproteinase (MMP) gene may influence the biological function of these enzymes and change their role in carcinogenesis and progression. The effect of MMP2 C-1306T and MMP9 C-1562T polymorphisms on genetic susceptibility has been investigated in various kinds of cancer. However, the relationship between these polymorphisms and risk of recurrence of hepatocellular carcinoma (HCC) after liver transplantation (LT) has not been reported. The present study was designed to investigate the association of these two loci with the risk of HCC recurrence in 93 HCC patients treated with LT. Genotyping was performed using direct DNA sequencing. For MMP2 C-1306T variant, patients with CT heterozygous conferred a 58% reduction in recurrence risk (risk ratio: 0.419; 95% confidence interval: 0.177-0.994). The mean recurrence-free survival for CT genotype was significantly longer than that for homozygous CC patients (30.4 vs 19.3 months, p = 0.019). However, no association was found between MMP9 C-1562T polymorphisms and recurrence of HCC (p = 0.259). These findings suggest that MMP2 promoter polymorphisms may provide some predictive value for HCC recurrence after LT.

Iron chelation by clinically relevant anthracyclines: alteration in expression of iron-regulated genes and atypical changes in intracellular iron distribution and trafficking

Anthracyclines are effective anticancer agents. However, their use is limited by cardiotoxicity, an effect linked to their ability to chelate iron and to perturb iron metabolism (Mol Pharmacol 68:261-271, 2005). These effects on iron-trafficking remain poorly understood, but they are important to decipher because treatment for anthracycline cardiotoxicity uses the chelator, dexrazoxane. Incubation of cells with doxorubicin (DOX) up-regulated mRNA levels of the iron-regulated genes transferrin receptor-1 (TfR1) and N-myc downstream-regulated gene-1 (Ndrg1). This effect was mediated by iron depletion, because it was reversed by adding iron and it was prevented by saturating the anthracycline metal binding site with iron. However, DOX did not act like a typical chelator, because it did not induce cellular iron mobilization. In the presence of DOX and (59)Fe-transferrin, iron-trafficking studies demonstrated ferritin-(59)Fe accumulation and decreased cytosolic-(59)Fe incorporation. This could induce cytosolic iron deficiency and increase TfR1 and Ndrg1 mRNA. Up-regulation of TfR1 and Ndrg1 by DOX was independent of anthracycline-mediated radical generation and occurred via hypoxia-inducible factor-1alpha-independent mechanisms. Despite increased TfR1 and Ndrg1 mRNA after DOX treatment, this agent decreased TfR1 and Ndrg1 protein expression. Hence, the effects of DOX on iron metabolism were complex because of its multiple effector mechanisms.

Formation and microbial community analysis of chloroanilines-degrading aerobic granules in the sequencing airlift bioreactor

AIMS

This paper investigates a selection-based acclimation strategy for improving the performance and stability of aerobic granules at a high chloroanilines loading.

METHODS AND RESULTS

The experiments were conducted in a sequencing airlift bioreactor (SABR) to develop aerobic granules fed with chloroanilines (ClA). The evolution of aerobic granulation was monitored using image analysis and scanning electron microscopy, and PCR-DGGE analysis of microbial community was performed. The sludge granulation was apparently developed by decreased settling time and gradual increased ClA loading to 0.8 kg m(-3) day(-1). A steady-state performance of the granular SABR was reached at last, as evidenced by biomass concentration of 6.3 g l(-1) and constant ClA removal efficiency of 99.9%. The mature granules had a mean size of 1.55 mm, minimal settling velocity of 68.4 m h(-1), specific ClA degradation rate of 0.181 g gVSS(-1) day(-1). Phylogenetic analysis of aerobic ClA-degrading granules confirmed the dominance of beta-, gamma-Proteobacteria and Flavobacteria.

CONCLUSIONS

The chosen operating strategy involving step increase in ClA loading and enhancement of major selection pressures was successful in cultivating the aerobic ClA-degrading granules.

SIGNIFICANCE AND IMPACT OF THE STUDY

This research could be helpful for improving the stability of aerobic granules via optimizing operating conditions and developing economic feasible full-scale granular bioreactor.

Prevalence and expression of the plasmid-mediated quinolone resistance determinant qnrA1

Since its discovery, qnrA has been found in most common Enterobacteriaceae. Ciprofloxacin MICs conferred by different qnrA-positive plasmids could range from 0.1 microg/ml to 2 microg/ml in Escherichia coli J53. The reasons for different ciprofloxacin MICs conferred by qnrA have not been fully clarified. Five hundred forty-one consecutive gram-negative clinical strains that were resistant or intermediate to ciprofloxacin and that were isolated in Shanghai in 2005 were screened for qnrA by PCR. For qnrA-positive isolates, the transferability of quinolone resistance was determined by conjugation and mutations within the quinolone resistance-determining region (QRDR) of gyrA and parC. aac(6')-Ib-cr was detected and qnrA RNA expression was determined using real-time reverse transcription-PCR for transconjugants with different ciprofloxacin MICs. The qnrA gene was detected in 7 of the 541 clinical isolates. Quinolone resistance was transferred in four strains by conjugation. Mutations in the QRDR of gyrA and parC were detected in five qnrA-positive clinical strains with higher ciprofloxacin MICs. Of four qnrA-bearing plasmids in E. coli J53, pHS4 and pHS5 conferred ciprofloxacin MICs of 0.094 to 0.125 microg/ml; pHS3, which harbored the aac(6')-Ib-cr gene as well, conferred a ciprofloxacin MIC of 0.25 microg/ml, and pHS6, which had both the aac(6')-Ib-cr gene and a high expression level of qnrA, had a ciprofloxacin MIC of 1.0 microg/ml. The prevalence of qnrA appeared to be higher in Enterobacter cloacae than in other Enterobacteriaceae. The coexistence of qnrA and aac(6')-Ib-cr in a single plasmid and increased qnrA expression can account for the different levels of ciprofloxacin resistance seen in transconjugants.

Kit-like immunoreactivity in the zebrafish gastrointestinal tract reveals putative ICC

Gastrointestinal (GI) motility results from the coordinated actions of enteric neurons, interstitial cells of Cajal (ICC), and smooth muscle cells. The GI tract of the zebrafish has a cellular anatomy that is essentially similar to humans. Although enteric nerves and smooth muscle cells have been described, it is unknown if ICC are present in the zebrafish. Immunohistochemistry and PCR were used determine expression for the zebrafish Kit orthologue in the zebrafish gastrointestinal tract. Cells displaying Kit-like immunoreactivity were identified in the muscular layers of the adult zebrafish gastrointestinal tract. Two layers of Kit-positive cells were identified, one with multipolar cells located between the longitudinal and circular smooth muscle layers and one with simple bipolar cells located deep in the circular muscle layer. Primers specifically designed to amplify mRNA coding for two zebrafish kit genes, kita and kitb, and two kit ligands, kitla and kitlb, amplified the expected transcript from total RNA isolated from zebrafish GI tissues. The Sparse mutant, a kita null mutant, showed reduced contraction frequency and increased size of the GI tract indicating a functional role for kita. These data establish the presence of a cellular network with Kit-like immunoreactivity in the myenteric plexus region of the zebrafish GI tract, adjacent to enteric neurons. Expression of kita and kitb, and the ligands kitla and kitlb, were verified in the adult GI tract. The anatomical arrangement of the Kit-positive cells strongly suggests that they are ICC.

Fibrinogen controls human platelet fibronectin internalization and cell-surface retention

BACKGROUND

We recently demonstrated that platelet aggregation occurred in fibrinogen-deficient mice. In these animals, platelet fibronectin (Fn) content was increased 3-5 fold, suggesting that Fn may also be involved in platelet aggregation.

METHODS AND RESULTS

We compared platelet Fn content from a severe hypofibrinogenemic patient (with approximately 0.5% of normal fibrinogen levels) with his parents (heterozygous) and healthy donors. A significant increase in the patient's platelet Fn content was detected by immunoblot, flow cytometry, and immunoelectron microscopy (IEM). To examine the possible contribution of platelet Fn to platelet aggregation, we examined cell-surface Fn expression after thrombin treatment. Unexpectedly, IEM detected only trace amounts of Fn retained on the patient's platelet surface, and flow cytometry indicated that surface Fn was approximately 6-fold lower than that of his parents and tenfold lower than that of healthy donors. An ELISA further confirmed that the patient's platelet Fn was primarily released into the extracellular medium. To test whether retention of surface Fn was due to fibrin formation on the platelet surface, an antifibrin antibody (T2 G1) was employed. Fibrin was detected on platelets from healthy donors and from the father, but was negligible on the patient's platelets. Consistent with these data, when gel-filtered platelets of healthy donors were treated with thrombin receptor activation peptide (SFLLRN-NH(2); no conversion of fibrinogen to fibrin), little surface Fn was detected.

CONCLUSION

Fibrinogen not only competitively inhibits human platelet Fn internalization but also controls platelet-surface Fn retention via fibrin formation. The Fn-fibrin interaction is one possible mechanism to promote Fn interaction with platelets.