A new procedure for treatment of oily slurry using geotextile filters

A new procedure to mitigate the environmental impacts and reduce the cost of disposal of oil slurry is present in this paper. Waste from the petroleum industry has a high environmental impact. Systems for oil-water separation have been used to mitigate the contamination potential of these types of effluents. At the outlet of these systems, the oil is skimmed-off the surface, while the slurry is removed from the base. Due to the high concentration of contaminants, the disposal of this slurry is an environmentally hazardous practice. Usually this type of waste is disposed of in tanks or landfills after removal from the industrial plant. Basically, the proposed procedure utilizes drying beds with geotextile filters to both reduce the water content in the slurry and obtain a less contaminated effluent. Laboratory tests were carried out to simulate the drying system. Four types of filters were analyzed: two non-woven geotextiles, one woven geotextile, and a sand filter.

The delta region of outer-capsid protein micro 1 undergoes conformational change and release from reovirus particles during cell entry

Cell entry by reoviruses requires a large, transcriptionally active subvirion particle to gain access to the cytoplasm. The features of this particle have been the subject of debate, but three primary candidates-the infectious subvirion particle (ISVP), ISVP*, and core particle forms-that differ in whether putative membrane penetration protein micro 1 and adhesin sigma1 remain particle bound have been identified. Experiments with antibody reagents in this study yielded new information about the steps in particle disassembly during cell entry. Monoclonal antibodies specific for the delta region of micro 1 provided evidence for a conformational change in micro 1 and for release of the delta proteolytic fragment from entering particles. Antiserum raised against cores provided evidence for entry-related changes in particle structure and identified entering particles that largely lack the delta fragment inside cells. Antibodies specific for sigma1 showed that it is also largely shed from entering particles. Limited coimmunostaining with markers for late endosomes and lysosomes indicated the particles lacking delta and sigma1 did not localize to those subcellular compartments, and other observations suggested that both the particles and free delta were released into the cytoplasm. Essentially equivalent findings were obtained with native ISVPs and highly infectious recoated particles containing wild-type proteins. Poorly infectious recoated particles containing a hyperstable mutant form of micro 1, however, showed no evidence for the in vitro and intracellular changes in particle structure normally detected by antibodies, and these particles instead accumulated in late endosomes or lysosomes. Recoated particles with hyperstable micro 1 were also ineffective at mediating erythrocyte lysis in vitro and promoting alpha-sarcin coentry and intoxication of cells in cultures. Based on these and other findings, we propose that ISVP* is a transient intermediate in cell entry which mediates membrane penetration and is then further uncoated in the cytoplasm to yield particles, resembling cores, that largely lack the delta fragment of micro 1.

Effects of dynamin inactivation on pathways of anthrax toxin uptake

Internalization and traffic to acidic endosomes of anthrax lethal factor (LF) and protective antigen (PA), bound to the anthrax toxin receptor (ATR), is required for LF translocation into the cytosol, where it can elicit its toxic effects. Dynamin is required for clathrin-mediated endocytosis, and long-term disruption of dynamin function blocks internalization of PA. We have used LFn-DTA, a surrogate of LF consisting of the N-terminal domain of LF fused to the catalytic subunit of diphtheria toxin, to differentiate the effects of acute and long-term block of dynamin function on LFn-DTA toxicity. Both forms of interference reduce LFn-DTA toxicity only partially, consistent with alternative routes for LFn-DTA endocytosis. In contrast, a long-term block of dynamin activity results in a further interference with LFn-DTA toxicity that is consistent with an altered endosomal environment, probably an increase in endosomal pH.

Initiation of Smad-dependent and Smad-independent signaling via distinct BMP-receptor complexes

BACKGROUND

BMP-2 (bone morphogenetic protein-2) signals via two types of transmembrane serine/threonine kinase receptors (BRI and BRII), which form heteromeric complexes prior to and after ligand binding. Within a BMP-bound receptor complex, BRII transphosphorylates and activates BRI-a for further signaling. We investigated which signaling pathway is initiated by BMP-2 via preformed receptor complexes versus BMP-2-induced signaling receptor complexes.

METHODS

Immunofluorescence co-patching was used to study the oligomerization of receptors at the surface of live cells. Binding and chemical cross-linking of iodinated BMP-2 followed by immunoprecipitation was used to show association of receptors in the presence of ligand. Western blots with use of anti-phospho-Smad1 antibodies and reporter gene assays with use of SBE-lux were employed to show activation of the Smad pathway. Phosphorylation of p38-MAPK was shown by Western blots. Induction of alkaline phosphatase was determined by staining the cells. The cluster density of receptors was determined with use of image correlation spectroscopy.

RESULTS AND CONCLUSION

We showed that the Smad pathway is induced by preformed receptor complexes, whereas BMP-2-induced signaling complexes result in the activation of p38-MAPK. We also found evidence that the clustering of BRI-a at the membrane is altered in the presence of BRII, suggesting that it associates with existing clusters of BRII to initiate efficient Smad signaling. These data clearly demonstrate that it is critical to fully understand receptor oligomerization in order to estimate signaling outcome for distinct receptor and ligand mutants.

Prolonged culture of normal chorionic villus cells yields ICF syndrome-like chromatin decondensation and rearrangements

Untreated cultures from normal chorionic villus (CV) or amniotic fluid-derived (AF) samples displayed dramatic cell passage-dependent increases in aberrations in the juxtacentromeric heterochromatin of chromosomes 1 or 16 (1qh or 16qh). They showed negligible levels of chromosomal aberrations in primary culture and no other consistent chromosomal abnormality at any passage. By passage 8 or 9, 82 +/- 7% of the CV metaphases from all eight studied samples exhibited 1qh or 16qh decondensation and 25 +/- 16% had rearrangements in these regions. All six analyzed late-passage AF cultures displayed this regional decondensation and recombination in 54 +/- 16 and 3 +/- 3% of the metaphases, respectively. Late-passage skin fibroblasts did not show these aberrations. The chromosomal anomalies resembled those diagnostic for the ICF syndrome (immunodeficiency, centromeric region instability, and facial anomalies). ICF patients have constitutive hypomethylation at satellite 2 DNA (Sat2) in 1qh and 16qh, generally as the result of mutations in the DNA methyltransferase gene DNMT3B. At early and late passages, CV DNA was hypomethylated and AF DNA was hypermethylated both globally and at Sat2. DNMT1, DNMT3A, or DNMT3B RNA levels did not differ significantly between CV and AF cultures or late and early passages. The high degree of methylation of Sat2 in late-passage AF cells indicates that hypomethylation of this repeat is not necessary for 1qh decondensation. Sat2 hypomethylation may nonetheless favor 1qh and 16qh anomalies because CV cultures, with their Sat2 hypomethylation, displayed 1qh and 16qh decondensation and rearrangements at significantly lower passage numbers than did AF cultures. Also, CV cultures had much higher ratios of ICF-like rearrangements to heterochromatin decondensation in chromosomes 1 and 16. These cultures may serve as models to help elucidate the biological consequences of cancer-associated satellite DNA hypomethylation.

Transforming growth factor-beta receptors interact with AP2 by direct binding to beta2 subunit

Transforming growth factor-beta (TGF-beta) superfamily members regulate a wide range of biological processes by binding to two transmembrane serine/threonine kinase receptors, type I and type II. We have previously shown that the internalization of these receptors is inhibited by K(+) depletion, cytosol acidification, or hypertonic medium, suggesting the involvement of clathrin-coated pits. However, the involvement of the clathrin-associated adaptor complex AP2 and the identity of the AP2 subunit that binds the receptors were not known. Herein, we have studied these issues by combining studies on intact cells with in vitro assays. Using fluorescence photobleaching recovery to measure the lateral mobility of the receptors on live cells (untreated or treated to alter their coated pit structure), we demonstrated that their mobility is restricted by interactions with coated pits. These interactions were transient and mediated through the receptors' cytoplasmic tails. To measure direct binding of the receptors to specific AP2 subunits, we used yeast two-hybrid screens and in vitro biochemical assays. In contrast to most other plasma membrane receptors that bind to AP2 via the mu2 subunit, AP2/TGF-beta receptor binding was mediated by a direct interaction between the beta2-adaptin N-terminal trunk domain and the cytoplasmic tails of the receptors; no binding was observed to the mu2, alpha, or sigma2 subunits of AP2 or to mu1 of AP1. The data uniquely demonstrate both in vivo and in vitro the ability of beta2-adaptin to directly couple TGF-beta receptors to AP2 and to clathrin-coated pits, providing the first in vivo evidence for interactions of a transmembrane receptor with beta2-adaptin.

New and rapid fully automated method for determination of tazobactam and piperacillin in fatty tissue and serum by column-switching liquid chromatography

A sensitive and rapid HPLC assay for determining tazobactam and piperacillin in fatty tissue and serum is described. While the common methods need liquid-liquid extraction before the injection in a automated column switching HPLC, the new method works by direct injection of the filtered tissue extract or diluted serum in a automated column switching HPLC without any other pre-treatment. This was performed by the use of a NH2-precolumn and enrichment/transfer at different pH-level. During the analyses, the NH2-precolumn was automatically regenerated with acetonitrile-water. The chromatogram peaks for piperacillin and tazobactam were identified by the retention time and quantified by peak area. The calibration curve was linear between 1 and 16 microg/ml. The quantification limit of tazobactam was about 1 microg/ml in fatty tissue extracts and in diluted serum (calculated for pure serum 2 microg/ml), respectively. For piperacillin it was less. The described procedure allows sample clean-up and determination of the antibiotic within 35 min. The chromatograms with this easy sample treatment had the same quantity of matrix peaks and in contrast to liquid-liquid extraction no loss of piperacillin. Because of the automatically rinsing of the NH2-precolumn during the chromatographic separation, more than 50 different biological samples could be measured with one NH2-precolumn without loss of performance.

Endoluminal stent-graft placement in patients with acute aortic dissection type B

OBJECTIVES

This study was performed to evaluate the feasibility, safety and effectiveness of endovascular stent-grafting in treating Stanford type B acute aortic dissection. We describe our first clinical experiences and initial results with stent-grafting across the primary entry tear in patients with acute aortic dissection type B.

METHODS

Between March 2000 and August 2001, nine patients with acute type B dissection were treated endoluminally by stent-graft implantation. There were seven male and two female patients with a mean age of 63 years (between 48 and 85 years). In all nine patients aortic dissection was diagnosed by multislice computed tomography (CT) angiography. All nine patients had a maximal aortic diameter of 5.5 cm or more and recurrent pain, one patient showed hemoptysis. This patient with signs of a contained rupture was treated under emergency condition, the eight remaining patients were in hemodynamic stabile condition at the time of intervention. The GORE Excluder stent-graft system was used in eight patients (mean 1.8 stents/patient) and the TALENT stent-graft system in one patient, which were introduced transfemorally.

RESULTS

The primary entry tear could be sealed successfully in all nine patients. Complete thrombosis of the false thoracic aortic lumen was obtained in two patients, in the remaining seven patients the false lumen was obliterated in the area of the thoracic aorta but perfused via re-entries in the abdominal region. No severe intraoperative complications occurred. One patient developed bilateral incomplete paraplegia with motor and sensory deficits affecting completely the right leg and partially the left leg, 14 h after intervention. A cerebrospinal fluid drainage was initiated by inserting a lumbar catheter. All nine patients, including the patient with the transient paraplegia, could be discharged from the hospital in excellent condition and without remaining neurologic deficits. Control CT scans showed a reduction of the false lumen from 2.34+/-0.58 to 0.7+/-0.44 cm and an increase of the true lumen from 1.56+/-0.5 to 4.10+/-0.6 cm in the thoracic aortic region. Mean ICU stay was 1.8 days, mean postoperative hospital stay was 7.6 days.

CONCLUSIONS

Stent-grafting of acute type B dissections may represent a very effective and promising new method by closure of the primary entry tear, thereby minimizing the risk of rupture of the thoracic aorta and optimizing distal perfusion by decompression of the true lumen.

The mode of bone morphogenetic protein (BMP) receptor oligomerization determines different BMP-2 signaling pathways

Bone morphogenetic proteins (BMPs) are multifunctional proteins regulating cell growth, differentiation, and apoptosis. BMP-2 signals via two types of receptors (BRI and BRII) that are expressed at the cell surface as homomeric as well as heteromeric complexes. Prior to ligand binding, a low but measurable level of BMP-receptors is found in preformed hetero-oligomeric complexes. The major fraction of the receptors is recruited into hetero-oligomeric complexes only after ligand addition. For this, BMP-2 binds first to the high affinity receptor BRI and then recruits BRII into the signaling complex. However, ligand binding to the preformed complex composed of BRII and BRI is still required for signaling, suggesting that it may mediate activating conformational changes. Using several approaches we have addressed the following questions: (i) Are preformed complexes incompetent of signaling in the absence of BMP-2? (ii) Which domains of the BRII receptors are essential for this complex formation? (iii) Are there differences in signals sent from BMP-induced versus preformed receptor complexes? By measuring the activation of Smads, of p38 MAPK and of alkaline phosphatase, we show that the ability of kinase-deficient BRII receptor mutants to inhibit BMP signaling depends on their ability to form heteromeric complexes with BRI. Importantly, a BRII mutant that is incapable in forming preassembled receptor complexes but recruits into a BMP-induced receptor complex does not interfere with the Smad pathway but does inhibit the induction of alkaline phosphatase as well as p38 phosphorylation. These results indicate that signals induced by binding of BMP-2 to preformed receptor complexes activate the Smad pathway, whereas BMP-2-induced recruitment of receptors activates a different, Smad-independent pathway resulting in the induction of alkaline phosphatase activity via p38 MAPK.

Acute type A aortic dissection: the prognostic impact of preoperative cardiac tamponade

OBJECTIVE

Acute type A aortic dissection requires emergency surgery and is associated with considerable mortality. The aim of the study was to evaluate whether occurrence of preoperative cardiac tamponade with or without palpable pulses in these patients is associated with higher incidence of multiple organ failure (MOF) and in-hospital mortality.

METHODS

A retrospective cohort study included 87 patients with acute type A aortic dissection, who were admitted via an emergency department between December 1991 and December 1999 for emergency surgery. Impending cardiac tamponade (with palpable pulses) and severe cardiac tamponade (without palpable pulses) were recorded and patients were followed for occurrence of MOF and/or in-hospital mortality.

RESULTS

Impending cardiac tamponade with palpable pulses was diagnosed in 33 patients (38%), signs of severe cardiac tamponade without palpable pulses were found in seven patients (8%). MOF occurred in 41 patients (47%); 32 patients (37%) died during the present stay, all of them had MOF. Preoperative severe cardiac tamponade without palpable pulses was associated with a significantly increased risk for poor outcome (odds ratio (OR)=16.1, 70% confidence interval (CI) 4.8-71.7, P=0.04), particularly preoperative death (n=6 of 7). Impending cardiac tamponade with palpable pulses (OR=1.6, 70% CI 0.8-3.3, P=0.2) was not associated with the occurrence of MOF/death. Hemodynamic shock (OR=6.5, 70% CI 3.0-13.9, P=0.01) was also associated with poor outcome.

CONCLUSION

Patients with acute type A aortic dissection and signs of preoperative cardiac tamponade without palpable pulses had a 16-fold increased risk for poor outcome, particularly preoperative death. In contrast, cardiac tamponade with palpable pulses was not associated with increased frequency of MOF/in-hospital mortality.

DNA methyltransferase 3B mutations linked to the ICF syndrome cause dysregulation of lymphogenesis genes

ICF (immunodeficiency, centromeric region instability and facial anomalies) is a recessive disease caused by mutations in the DNA methyltransferase 3B gene (DNMT3B). Patients have immunodeficiency, chromosome 1 (Chr1) and Chr16 pericentromeric anomalies in mitogen-stimulated lymphocytes, a small decrease in overall genomic 5-methylcytosine levels and much hypomethylation of Chr1 and Chr16 juxtacentromeric heterochromatin. Microarray expression analysis was done on B-cell lymphoblastoid cell lines (LCLs) from ICF patients with diverse DNMT3B mutations and on control LCLs using oligonucleotide arrays for approximately 5600 different genes, 510 of which showed a lymphoid lineage-restricted expression pattern among several different lineages tested. A set of 32 genes had consistent and significant ICF-specific changes in RNA levels. Half of these genes play a role in immune function. ICF-specific increases in immunoglobulin (Ig) heavy constant mu and delta RNA and cell surface IgM and IgD and decreases in Ig(gamma) and Ig(alpha) RNA and surface IgG and IgA indicate inhibition of the later steps of lymphocyte maturation. ICF-specific increases were seen in RNA for RGS1, a B-cell specific inhibitor of G-protein signaling implicated in negative regulation of B-cell migration, and in RNA for the pro-apoptotic protein kinase C eta gene. ICF-associated decreases were observed in RNAs encoding proteins involved in activation, migration or survival of lymphoid cells, namely, transcription factor negative regulator ID3, the enhancer-binding MEF2C, the iron regulatory transferrin receptor, integrin beta7, the stress protein heme oxygenase and the lymphocyte-specific tumor necrosis factor receptor family members 7 and 17. No differences in promoter methylation were seen between ICF and normal LCLs for three ICF upregulated genes and one downregulated gene by a quantitative methylation assay [combined bisulfite restriction analysis (COBRA)]. Our data suggest that DNMT3B mutations in the ICF syndrome cause lymphogenesis-associated gene dysregulation by indirect effects on gene expression that interfere with normal lymphocyte signaling, maturation and migration.

Methylation of the FSHD syndrome-linked subtelomeric repeat in normal and FSHD cell cultures and tissues

Facioscapulohumeral muscular dystrophy (FSHD) has an unusual molecular etiology. In a putatively heterochromatic subtelomeric region of each chromosome 4 homologue (4q35), unaffected individuals have 11 to about 95 tandem copies of a complex 3.3-kb repeat (D4Z4). Most FSHD patients have less than 10 copies at one allelic 4q35. This has been proposed to lead to the loss of heterochromatinization and, thereby, inappropriate gene expression by position effects, explaining the dominant nature of FSHD and the role of a decreased number of copies of D4Z4 at 4q35 but not at 10q26. Consistent with the proposed heterochromatinization of this repeat, by Southern blot analysis, we found that SmaI, MluI, SacII, and EagI sites in D4Z4 are highly methylated in normal and FSHD cell lines and somatic tissues, including skeletal muscle. Like repeated DNA sequences in the juxtacentromeric heterochromatin of chromosomes 1, 9, and 16, D4Z4 was hypomethylated at numerous CpGs in sperm and in cell lines from patients with an unrelated DNA methyltransferase deficiency syndrome (ICF; immunodeficiency, centromeric region instability, facial anomalies) in contrast to its hypermethylation in non-ICF postnatal somatic tissues. Our data on FSHD samples suggest that the disease-associated 4q35 D4Z4 repeats, which constitute a small percentage of the total D4Z4 repeats, are not generally hypomethylated relative to the other repeats of this sequence. However, in individuals not affected with FSHD, the hypermethylation of tandem, high-copy-number D4Z4 repeats might help stabilize heterochromatinization at allelic 4q35 regions just as hypermethylation elsewhere in the genome has been linked to chromatin compaction.

ABL1 promoter methylation can exist independently of BCR-ABL transcription in chronic myeloid leukemia hematopoietic progenitors

Formation of the hybrid BCR-ABL gene is responsible for >95% of chronic myeloid leukemia (CML). The alternative, downstream ABL promoter (Pa), which is usually retained in this chimeric oncogene, was reported to be methylated in many CML patients, but there has been controversy as to whether this methylation is a frequent change in bone marrow (BM) in early chronic phase (CP) or only past this stage. Also, the relevance of Pa promoter methylation to BCR-ABL expression in CML is unclear. We examined methylation of the ABL Pa promoter in uncultured BM samples and in colonies derived from their hematopoietic precursor cells by bisulfite and PCR-based assays (combined bisulfite restriction analysis and methylation-specific PCR). BM from seven CP CML patients at diagnosis had about 20-60% of the copies of the ABL Pa promoter methylated. No Pa methylation was detected in normal BMs or colonies derived from them. In contrast, most colonies from CP CML patients had Pa methylation. Surprisingly, 18-49% of the CML-derived colonies with this methylation reproducibly had no detectable BCR-ABL RNA on nested reverse transcription-PCR. Furthermore, the percentage of BCR-ABL RNA-positive colonies was almost same among the colonies not displaying Pa methylation as among the colonies in which this methylation was found. We conclude that ABL Pa methylation is often an early marker of CML in hematopoietic precursors and in total mononuclear BM cells but that it is not associated with an increased frequency of BCR-ABL RNA-positive cells. This methylation might be emblematic of cancer-associated hypermethylation elsewhere in the genome with the consequent silencing of tumor suppressor genes seen in many malignancies.

A new and rapid method for monitoring the new oxazolidinone antibiotic linezolid in serum and urine by high performance liquid chromatography-integrated sample preparation

A sensitive and rapid HPLC-assay for determining the new oxazolidinone antibiotic linezolid in serum and urine is described. HPLC-integrated sample preparation permits the direct injection of serum and urine samples without any pre-treatment. The in-line extraction technique is realized by switching automatically from the extraction column to the analytical column. After the matrix has passed the extraction column the retained analyte will be quantitatively transferred to the analytical column where separation by isocratic HPLC will be performed. Linezolid is detected according to its absorption maximum at 260 nm. The quantification limits are estimated to be 0.3 and 0.5 microg/ml in serum and urine samples, respectively. The described procedure allows sample clean-up and determination of the antibiotic within 20 min, thereby facilitating drug-monitoring in clinical routine.

A single internalization signal from the di-leucine family is critical for constitutive endocytosis of the type II TGF-(β) receptor

Endocytosis has an important contribution to the regulation of the surface expression levels of many receptors. In spite of the central role of the transforming growth factor (β) (TGF-(β)) receptors in numerous cellular and physiological processes, their endocytosis is largely unexplored. Current information on TGF-(β) receptor endocytosis relies exclusively on studies with chimeric constructs containing the extracellular domain of the GM-CSF receptors, following the internalization of the GM-CSF ligand; the conformation and interactions of the chimeric receptors (and therefore their endocytosis) may differ considerably from those of the native TGF-(β) receptors. Furthermore, there are no data on the potential endocytosis motif(s) of the TGF-(β) receptors or other receptor Ser/Thr kinases. Here, we report the use of type II TGF-(β) receptors, myc-tagged at their extracellular terminus, to investigate their endocytosis. Employing fluorescent antibody fragments to label exclusively the cell surface myc-tagged receptors exposed to the external milieu, made it possible to follow the internalization of the receptors, without the complications that render labeling with TGF-(β) (which binds to many cellular proteins) unsuitable for such studies. The results demonstrate that the full-length type II TGF-(β) receptor undergoes constitutive endocytosis via clathrin-coated pits. Using a series of truncation and deletion mutants of this receptor, we identified a short peptide sequence (I(218)I(219)L(220)), which conforms to the consensus of internalization motifs from the di-leucine family, as the major endocytosis signal of the receptor. The functional importance of this sequence in the full-length receptor was validated by the near complete loss of internalization upon mutation of these three amino acids to alanine.

Rapid antibiotic drug monitoring: meropenem and ceftazidime determination in serum and bronchial secretions by high-performance liquid chromatography-integrated sample preparation

A sensitive and rapid HPLC assay for the determination of the beta-lactam antibiotics ceftazidime and meropenem in serum and bronchial secretions is described. HPLC-integrated sample preparation allows direct injection of serum samples without any pretreatment. Sputum samples need only a simple homogenisation and volume measurement but no liquefying reagents are necessary. The inline extraction technique is realized by automatically switching from the extraction column to the analytical column. After the matrix passed the extraction column, the retained analyte is quantitatively transferred to the analytical column where separation by isocratic HPLC is performed. Ceftazidime and meropenem are detected according to their absorption maxima at 258 and 296 nm, respectively. The detection limit of both antibiotics is estimated to be better than 0.5 microg/ml in serum as well as in sputum samples. The described procedure allows determination of the antibiotics within 30-45 min, thereby facilitating drug monitoring in clinical routine.