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PubMed2005

CT enteroclysis: technique and clinical applications.

CT enteroclysis (CTE) has been gradually evolving with technical developments of spiral and multidetector row CT technology. It has nowadays become a well-defined imaging modality for the evaluation of various small bowel disorders. Volume challenge of 2L of enteral contrast agent administrated to the small bowel via a nasojejunal catheter ensures luminal distension, the prerequisite for the detection of mural abnormalities, also facilitating the accurate visualization of intraluminal lesions. CT acquisition is centered on small bowel loops, reconstructed in thin axial slices and completed by multiplanar views. Image analysis is essentially done in cine-mode on work-stations. CTE is of particular diagnostic value in intermediate or advanced stages of Cohn's disease, including the depiction of extraintestinal complications. It has become the imaging modality of choice for the localization and characterization of small bowel tumors. The cause and degree of low-grade small bowel obstruction is more readily analyzed with the technique of CTE than conventional CT. Limitations of CTE concern the assessment of pure intestinal motility disorders, superficial mucosal lesions and arteriovenous malformations of the small bowel, which are not consistently visualized. CTE should be selectively used to answer specific questions of the small bowel. It essentially contributes to the diagnostic quality of modern small bowel imaging, and therefore deserves an established, well-defined place among the other available techniques.

Contrast Media↗
PubMed2006

Three-dimensional MDCT imaging and CT esophagography for evaluation of esophageal tumors: preliminary study.

The aim of this study was to determine whether multidetector computed tomography (MDCT) imaging, including CT esophagography (CTE), can be used as a comprehensive imaging test for esophageal tumors. Twenty-three patients with esophageal neoplasms underwent MDCT with esophageal distension and endoscopy. Of them, 20 underwent barium study. Two radiologists independently reviewed MDCT images with 3D CT esophagography (CTE) including CT endoscopy and were asked to determine the presence of the esophageal lesions and characterize them using a five-point confidence scale. The radiologists' performance for the lesion detection and characterization was evaluated by receiver operating characteristic (ROC) analysis. They were also requested to determine the local staging of esophageal cancer, and the overall accuracies of MDCT for local staging were calculated. The ability of MDCT with CTE was also evaluated compared with conventional studies. CTE images successfully revealed 14 of 16 esophageal cancers and all seven submucosal tumors. Two esophageal cancers, both confined to the mucosal layer, were undetected. The Az values of the MDCT images were 0.954-0.957 for determining the presence of a lesion and 0.954-0.995 for differentiating between cancer and submucosal tumors. The overall accuracies for T and N staging were 42.9% and 85.7%, respectively. In 80% and 74% of cases, CTE gave similar or superior information to barium study and endoscopy, respectively. MDCT esophagography has the potential to serve as a comprehensive imaging modality for evaluating esophageal tumors as it provides accurate information regarding the detection and characterization of esophageal tumors as well as the similar information to conventional studies.

Adenocarcinoma↗
PubMed1991

A recombinant 70K protein ELISA. Screening for antibodies against U1snRNP proteins in human sera.

Antibodies to uridylic acid rich small nuclear ribonucleoprotein particles (UsnRNP) are mainly detected in patients with systemic lupus erythematosus (SLE) or mixed connective tissue disease (MCTD). Particularly those directed against epitopes of the 70K protein of U1snRNP serve as important markers for the diagnosis of MCTD. To establish an ELISA for determination of anti-70K protein antibodies in patients' sera a 1239 bp long cDNA insert coding for the epitopes of the 70K protein was ligated into a fusion expression vector. The bacterially expressed fusion protein was purified by chromatography on DEAE cellulose. Microtiter plates were coated with the fusion protein as well as with partially purified calf thymus extract (CTE) containing all natural UsnRNP antigens and RNase digested calf thymus extract (CTERNase) in which the natural 70K antigen was destroyed by the nuclease treatment. 10,888 sera of patients with suspected or overt rheumatic disease were analyzed for antibodies against these antigens simultaneously. Antibodies against CTE or CTERNase were not detected in 9123 sera, none of these showed reactivity with the 70K protein indicating a high degree of specificity of the assay. Positive results in each the 70K protein, CTE as well as the CTERNase ELISAs were obtained with 474 sera. 319 sera were only positive with CTE and 70K protein. Of these 793 anti-70K protein ELISA positive sera, 79% could be confirmed by immunoblot. Of 967 sera reacting with CTE and CTERNase but not with the recombinant 70K protein, 31% contained antibodies against various other UsnRNP proteins as shown by immunoblotting. 2.4% of these sera revealed also antibodies against the 70K protein. The use of the recombinant 70K protein as antigen meets the criterion for a simple and specific assay to detect anti-U1snRNP antibodies. Nevertheless, the sole use of this recombinant protein for anti-U1snRNP antibody screening may not be appropriate, because antibodies against other frequently occurring U1snRNP proteins (A, C) cannot be detected with this test. Therefore it should be used together with a natural UsnRNP antigen until further studies in patients with well established diagnoses will show whether natural antigens may be omitted.

Antibody Specificity↗
PubMed1989

Interleukin 2 responsive T cell clones from rheumatoid and normal subjects: proliferative responses to connective tissue elements.

In vivo-activated interleukin 2 responsive T cell clones were generated from peripheral blood (PB) and synovial fluid (SF) of rheumatoid arthritis (RA) patients and from normal control PB. The specificity of these clones was assessed by measuring proliferation induced by the connective tissue elements (CTE) collagen types I and II, native and denatured, proteoglycans, and irrelevant control antigens. The cloned T cells from RA patients but not from normal subjects responded in vitro with proliferation to all CTE but not to control antigens purified protein derivative, ovalbumin, or lysozyme. Proliferation occurred in the presence and absence of accessory cells (AC), but the responses were consistently higher in the presence of AC. Antibodies to HLA-DR abrogated the proliferative response to CTE suggesting that DR expression was necessary for the induction of proliferation. These findings demonstrate the existence of clonable T cells responsive to CTE in PB and SF of RA patients. Expression of reactivity to CTE may contribute to the chronicity of the inflammation in RA.

Arthritis, Rheumatoid↗
PubMed1987

Modulation of the reductive metabolism of halothane by microsomal cytochrome b5 in rat liver.

To study the modulation of the reductive metabolism of halothane (2-bromo-2-chloro-1,1,1-trifluoroethane) by microsomal cytochrome b5, formation of 2-chloro-1,1,1-trifluoroethane (CTE) and 2-chloro-1,1-difluoroethylene (CDE), major reduced metabolites of halothane, was analyzed in vivo and in vitro. Rats were pretreated with both malotilate (diisopropyl-1,3-dithiol-2-ylidenemalonate) and sodium phenobarbital (malotilate-treated rats) or only with sodium phenobarbital (control rats). The microsomes of malotilate-treated rats had significantly more cytochrome b5 than the controls, whereas the cytochrome P-450 content was not different between the two groups. At the end of 2-h exposure to 1% halothane in 14% oxygen, the ratio of CDE to CTE in arterial blood was significantly higher in malotilate-treated rats than in the controls. Under anaerobic conditions, the formation of CDE and the ratio of CDE to CTE were significantly greater in microsomal preparations of malotilate-treated rats than those of the controls. In a reconstituted system containing cytochrome P-450PB purified from rabbit liver, addition of cytochrome b5 to the system enhanced the formation of CDE and increased the ratio of CDE to CTE. These results suggested that cytochrome b5 enhances the formation ratio of CDE to CTE by stimulating the supply of a second electron to cytochrome P-450, which might reduce radical reactions in the reductive metabolism of halothane.

Anaerobiosis↗
PubMed2004

Effects of discontinuation as well as intervention of cyclic therapy with etidronate on bone remodeling after cementless total hip arthroplasty.

We previously reported the effects of cyclic therapy with etidronate (CTE) on periprosthetic bone mineral density (BMD) after cementless total hip arthroplasty (THA). This study aimed to evaluate the effects of withdrawal and intervention of CTE after cementless THA. The control group consisted of 24 patients without osteoactive drugs. Sixteen patients continued on CTE (i.e., 400 mg/day oral etidronate for 2 weeks followed by 12 weeks of 500 mg/day calcium lactate, repeated every 14 weeks) for the first 12 months followed by no treatment for 18 months (early-etidronate group). Fifteen patients received no treatment for the first 18 months followed by CTE for 12 months (late-etidronate group). Periprosthetic BMD in seven regions of interest based on the zones of Gruen et al. was measured with dual energy X-ray absorptiometry at 3 weeks, 6, 12, 18, 24, and 30 months postoperatively. At 12 months after operation (off therapy point in the early-etidronate group), postoperative decreases of BMD in the early-etidronate group were significantly smaller than those in the control group in zones 1, 2, 5, 6, and 7 and those in the late-etidronate group in zones 1, 5, 6, and 7 (P < 0.05 for each). In the early-etidronate group, significant decreases in BMD were found during months 12-30 (off therapy period) after withdrawal of CTE in zones 1 and 7 (P < 0.05 for each). In the late-etidronate group, BMD increased significantly in zones 4 and 6 (P < 0.05 for each) during months 18-30 (on therapy period) after intervention trial, while in the controls, BMD decreased significantly in zone 3 (P < 0.05) over this period. At the final follow-up (30 months), BMD loss in zone 7 was significantly less in the early-etidronate group than in the other groups (P < 0.05). BMD changes in the early-etidronate group and late-etidronate group were associated with changes in biochemical bone markers.

Absorptiometry, Photon↗
PubMed2003

Analysis of synergy between divergent simple retrovirus posttranscriptional control elements.

Mason-Pfizer monkey virus (MPMV) and spleen necrosis virus (SNV) are simple retroviruses that encode functionally divergent cis-acting RNA elements that use cellular proteins to facilitate nuclear export and translation of unspliced viral RNA. We tested the hypothesis that a combination of MPMV constitutive transport element (CTE) and SNV or MPMV RU5 translational enhancer on unspliced HIV-1 gag-pol reporter RNA synergistically augments Gag production. Results of transient transfection assays validate the hypothesis of synergistic augmentation in COS cells, but not 293 cells. RNA targeting experiments verified comparable responsiveness to CTE-interactive proteins tethered by RRE and RevM10Tap in COS and 293 cells. Exogeneous expression of Tap and NXT1 was necessary and sufficient to rescue Gag augmentation in 293 cells. Overexpression experiments established that CTE, but not RU5, confers the responsiveness to Tap and NXT1 and that CTE in conjunction with Tap and NXT1 conferred a 30-fold increase in translational utilization of the cytoplasmic RNA. Our results uncovered a previously unidentified role of CTE in conjunction with Tap and NXT1 in commitment to efficient cytoplasmic RNA utilization.

5' Untranslated Regions↗
PubMed2001

Contrast-transfer efficiency for continuously varying tissue moduli: simulation and phantom validation.

This study consisted of two parts. In the first part, the contrast-transfer efficiency (CTE) in elastography was extended to account for continuous changes of modulus distribution. It was shown that, for a finite size background, the strain contrast approaches the modulus contrast in the case of Gaussian distributions. Thus, an increase in the CTE was obtained. For a fixed background size, it was shown that the CTE increases as the SD of the Gaussian distribution increases. This property was explained by the redistribution of strain concentrations at the inclusion/background interface. In the second part of the study, the CTE was verified experimentally. Six gelatin/agar/water-based phantoms embedding inclusions with modulus contrast varying between +/- 6 dB were manufactured. It was shown that the modulus at the interface inclusion/background was continuous and, in turn, resulted in an increase of the CTE as compared to the known case of a sharp boundary. The continuous inclusion/background interface was explained by the existence of an osmotic pressure gradient.

Agar↗
PubMed1979

Quantitative analysis of volatile halothane metabolites in biological tissues by gas chromatography.

A simple and sensitive gas chromatographic method for the determination of 2-chloro-1, 1-difluoroethylene (CDE) and 2-chloro-1,1,1-trifluoroethane (CTE), two highly volatile metabolites of halothane, in blood, liver and isolated hepatic microsomes is described. The entire head-space in equilibrium with a known volume or weight of the sample is injected into the gas chromatograph equipped with a flame ionization detector. Quantification is accomplished with standards prepared by fortifying blank samples with known concentrations of CDE and CTE which are treated under the same conditions as the samples. Detection limits for CDE and CTE were 2 pmole/ml in blood and 10 pmole/g in liver and the mean relative standard deviations are no greater than +/- 6% except for CTE in hepatic microsomes (+/- 9%). A preliminary study of blood CDE and CTE levels in humans anesthetized with halothane is reported.

Chromatography, Gas↗
PubMed2006

An intron with a constitutive transport element is retained in a Tap messenger RNA.

Alternative splicing is a key factor contributing to genetic diversity and evolution. Intron retention, one form of alternative splicing, is common in plants but rare in higher eukaryotes, because messenger RNAs with retained introns are subject to cellular restriction at the level of cytoplasmic export and expression. Often, retention of internal introns restricts the export of these mRNAs and makes them the targets for degradation by the cellular nonsense-mediated decay machinery if they contain premature stop codons. In fact, many of the database entries for complementary DNAs with retained introns represent them as artefacts that would not affect the proteome. Retroviruses are important model systems in studies of regulation of RNAs with retained introns, because their genomic and mRNAs contain one or more unspliced introns. For example, Mason-Pfizer monkey virus overcomes cellular restrictions by using a cis-acting RNA element known as the constitutive transport element (CTE). The CTE interacts directly with the Tap protein (also known as nuclear RNA export factor 1, encoded by NXF1), which is thought to be a principal export receptor for cellular mRNA, leading to the hypothesis that cellular mRNAs with retained introns use cellular CTE equivalents to overcome restrictions to their expression. Here we show that the Tap gene contains a functional CTE in its alternatively spliced intron 10. Tap mRNA containing this intron is exported to the cytoplasm and is present in polyribosomes. A small Tap protein is encoded by this mRNA and can be detected in human and monkey cells. Our results indicate that Tap regulates expression of its own intron-containing RNA through a CTE-mediated mechanism. Thus, CTEs are likely to be important elements that facilitate efficient expression of mammalian mRNAs with retained introns.

Alternative Splicing↗
PubMed1999

A role for RNA helicase A in post-transcriptional regulation of HIV type 1.

Retroviruses must bypass the tight coupling of splicing and nuclear export of mRNA in their replication cycle because unspliced genomic RNA and incompletely spliced mRNA must be exported to the cytoplasm for packaging or translation. This process is mediated by a cis-acting constitutive transport element (CTE) for simple retroviruses and by the trans-acting viral protein Rev in concert with its response element (RRE) for complex retroviruses (e.g., HIV). Recently, we identified RNA helicase A (RHA) as a potential cellular cofactor for CTE. Here, we report that RHA also plays a role in Rev/RRE-mediated gene expression and HIV replication. RHA binds weakly to HIV-1 RRE independently of Rev. Overexpression of RHA, but not of an RHA mutant lacking helicase activity, increased both Rev/RRE- and CTE-dependent gene expression and the levels of unspliced HIV mRNA. Microinjection of antibodies to RHA into nuclei dramatically inhibited both CTE- and Rev-dependent gene expression in human cells. Exogenous RHA cDNA, but not the mutant RHA, rescued this inhibition. We propose that RHA is required to release both CTE- and RRE-containing mRNA from spliceosomes before completion of splicing, thus freeing them for nuclear export.

Antibodies↗
PubMed1997

NMR spectroscopic studies of the DNA-binding domain of the monomer-binding nuclear orphan receptor, human estrogen related receptor-2. The carboxyl-terminal extension to the zinc-finger region is unstructured in the free form of the protein.

Unlike steroid and retinoid receptors, which associate with DNA as dimers, human estrogen related receptor-2 (hERR2) belongs to a growing subclass of nuclear hormone receptors that bind DNA with high affinity as monomers. A carboxyl-terminal extension (CTE) to the zinc-finger domain has been implicated to be responsible for determining the stoichiometry of binding by a nuclear receptor to its response element. To better understand the mechanism by which DNA specificity is achieved, the solution structure of the DNA-binding domain of hERR2 (residues 96-194) consisting of the two putative zinc fingers and the requisite 26-amino acid CTE was analyzed by multidimensional heteronuclear magnetic resonance spectroscopy. The highly conserved zinc-finger region (residues 103-168) has a fold similar to those reported for steroid and retinoid receptors, with two helices that originate from the carboxyl-terminal ends of the two zinc fingers and that pack together orthogonally, forming a hydrophobic core. The CTE element of hERR2 is unstructured and highly flexible, exhibiting nearly random coil chemical shifts, extreme sensitivity of the backbone amide protons to solvent presaturation, and reduced heteronuclear (1H-15N) nuclear Overhauser effect values. This is in contrast to the dimer-binding retinoid X and thyroid hormone receptors, where, in each case, a helix has been observed within the CTE. The implications of this property of the hERR2 CTE are discussed.

Alanine↗
PubMedDate not supplied

Neuropsychological deficits in patients diagnosed with chronic toxic encephalopathy: which tests are most discriminative?

Chronic toxic encephalopathy (CTE), a syndrome affecting the central nervous system, has been associated with long-term occupational exposure to organic solvents. We studied the discriminative power of a series of cognitive tests in separating 20 patients exposed to organic solvents, diagnosed with CTE, from 27 non-CTE patients with similar symptoms and exposure, and 19 healthy referents. All subjects were examined with a test battery assessing various cognitive and psychomotor functions. The groups were comparable with regard to age and level of schooling. Stepwise discriminant analyses indicated that tests assessing perceptual speed and attention were the most sensitive in distinguishing the CTE patients from the other patients as well as from the healthy referents. The CTE patients performed worse than the two other groups not only in tests assessing perceptual speed and attention, visual memory, and visuo-spatial skill but also, contrary to expectation, in a test of verbal ability.

Journal Article↗
PubMed2000

Analysis of cellular factors that mediate nuclear export of RNAs bearing the Mason-Pfizer monkey virus constitutive transport element.

There is now convincing evidence that the human Tap protein plays a critical role in mediating the nuclear export of mRNAs that contain the Mason-Pfizer monkey virus constitutive transport element (CTE) and significant evidence that Tap also participates in global poly(A)(+) RNA export. Previously, we had mapped carboxy-terminal sequences in Tap that serve as an essential nucleocytoplasmic shuttling domain, while others had defined an overlapping Tap sequence that can bind to the FG repeat domains of certain nucleoporins. Here, we demonstrate that these two biological activities are functionally correlated. Specifically, mutations in Tap that block nucleoporin binding also block both nucleocytoplasmic shuttling and the Tap-dependent nuclear export of CTE-containing RNAs. In contrast, mutations that do not inhibit nucleoporin binding also fail to affect Tap shuttling. Together, these data indicate that Tap belongs to a novel class of RNA export factors that can target bound RNA molecules directly to the nuclear pore without the assistance of an importin beta-like cofactor. In addition to nucleoporins, Tap has also been proposed to interact with a cellular cofactor termed p15. Although we were able to confirm that Tap can indeed bind p15 specifically both in vivo and in vitro, a mutation in Tap that blocked p15 binding only modestly inhibited CTE-dependent nuclear RNA export. However, p15 did significantly enhance the affinity of Tap for the CTE in vitro and readily formed a ternary complex with Tap on the CTE. This result suggests that p15 may play a significant role in the recruitment of the Tap nuclear export factor to target RNA molecules in vivo.

Amino Acid Sequence↗
PubMed2003

Sam68 enhances the cytoplasmic utilization of intron-containing RNA and is functionally regulated by the nuclear kinase Sik/BRK.

Cells normally restrict the nuclear export and expression of intron-containing mRNA. In many cell lines, this restriction can be overcome by inclusion of cis-acting elements, such as the Mason-Pfizer monkey virus constitutive transport element (CTE), in the RNA. In contrast, we observed that CTE-mediated expression from human immunodeficiency virus Gag-Pol reporters was very inefficient in 293 and 293T cells. However, addition of Sam68 led to a dramatic increase in the amount of Gag-Pol proteins produced in these cells. Enhancement of CTE function was not seen when a Sam68 point mutant (G178E) that is defective for RNA binding was used. Additionally, the effect of Sam68 was inhibited in a dose-dependent manner by coexpression of an activated form of the nuclear kinase Sik/BRK that hyperphosphorylated Sam68. RNA analysis showed that cytoplasmic Gag-Pol-CTE RNA levels were only slightly enhanced by the addition of Sam68, compared to a 60- to 70-fold increase in the levels of Gag-Pol protein expression. Thus, in this system, Sam68 functioned to enhance the cytoplasmic utilization of RNA containing the CTE. These results suggest that Sam68 may interact with specific RNAs in the nucleus to provide a "mark" that affects their cytoplasmic fate. They also provide further evidence of links between signal transduction and RNA utilization.

Adaptor Proteins, Signal Transducing↗
PubMed2005

Somatosensory evoked potential and EEG in children with focal idiopathic epilepsies with and without evoked spikes by tapping of the feet or hands.

The characteristics of SEP cortical components were studied in 40 children with focal idiopathic epilepsies of childhood. Twenty children had focal idiopathic epilepsies and evoked spikes (FIE-ES) on the EEG and 20 had benign focal epilepsy of childhood with centrotemporal spikes (CTE) but without evoked spikes (ES). These data were compared with those of a control group of 20 normal children. N35 high-amplitude component was more frequent in the CTE group than in the control group (p < 0.001). P98 showed high amplitude in 50% of the children of FIE-ES group, and in none of the CTE and control groups (p < 0.001). The P98 high amplitude component was more common in the FIE-ES group than in the other groups, and so was the N35 high amplitude component in the CTE group. Lateralization of high-amplitude components of N35 in the CTE group and of P98 in FIE group was not correlated with lateralization of epileptiform activity and evoked spikes. Based on our findings, there are SEPs cortical component differences in childhood focal idiopathic epilepsies according to occurrence or absence of ES.

Electroencephalography↗
PubMed2006

Structure of the progesterone receptor-deoxyribonucleic acid complex: novel interactions required for binding to half-site response elements.

The DNA binding domain (DBD) of nuclear hormone receptors contains a highly conserved globular domain and a less conserved carboxyl-terminal extension (CTE). Despite previous observations that the CTEs of some classes of nuclear receptors are structured and interact with DNA outside of the hexanucleotide hormone response element (HRE), there has been no evidence for such a CTE among the steroid receptors. We have determined the structure of the progesterone receptor (PR)-DBD-CTE DNA complex at a resolution of 2.5 A, which revealed binding of the CTE to the minor groove flanking the HREs. Alanine substitutions of the interacting CTE residues reduced affinity for inverted repeat HREs separated by three nucleotides, and essentially abrogated binding to a single HRE. A highly compressed minor groove of the trinucleotide spacer and a novel dimerization interface were also observed. A PR binding site selection experiment revealed sequence preferences in the trinucleotide spacer and flanking DNA. These results, taken together, support the notion that sequences outside of the HREs influence the DNA binding affinity and specificity of steroid receptors.

Alanine↗
PubMed2005

A quantitative look at fluorosis, fluoride exposure, and intake in children using a health risk assessment approach.

The prevalence of dental fluorosis in the United States has increased during the last 30 years. In this study, we used a mathematical model commonly employed by the U.S. Environmental Protection Agency to estimate average daily intake of fluoride via all applicable exposure pathways contributing to fluorosis risk for infants and children living in hypothetical fluoridated and nonfluoridated communities. We also estimated hazard quotients for each exposure pathway and hazard indices for exposure conditions representative of central tendency exposure (CTE) and reasonable maximum exposure (RME) conditions. The exposure pathways considered were uptake of fluoride via fluoridated drinking water, beverages, cow's milk, foods, and fluoride supplements for both age groups. Additionally, consumption of infant formula for infants and inadvertent swallowing of toothpaste while brushing and incidental ingestion of soil for children were also considered. The cumulative daily fluoride intake in fluoridated areas was estimated as 0.20 and 0.11 mg/kg-day for RME and CTE scenarios, respectively, for infants. On the other hand, the RME and CTE estimates for children were 0.23 and 0.06 mg/kg-day, respectively. In areas where municipal water is not fluoridated, our RME and CTE estimates for cumulative daily average intake were, respectively, 0.11 and 0.08 mg/kg-day for infants and 0.21 and 0.06 mg/kg-day for children. Our theoretical estimates are in good agreement with measurement-based estimates reported in the literature. Although CTE estimates were within the optimum range for dental caries prevention, the RME estimates were above the upper tolerable intake limit. This suggests that some children may be at risk for fluorosis.

Beverages↗