SEARCH · PubMed Health

Results for “Enhancer”

Explore indexed PubMed citations for clinical trials, systematic reviews and public health research. Read source abstracts and follow each citation to its original PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 469 records · Page 26Linked to original sources

PubMed1990

Nasal administration of a cognition enhancer provides improved bioavailability but not enhanced brain delivery.

Compound 1 [3,3-bis(4-pyridylmethyl)-1-phenylindolin-2-one] is an experimental cognition-enhancing drug now being developed for cognitive disorders. Oral bioavailability of 1 in rats was less than 10% of the dose. Nasal dosing improved bioavailability to greater than 50%. Brain levels of total radioactivity were measured after iv and nasal doses of radiolabeled 1. The ratio of AUCbrain:AUCplasma was the same by both routes, so nasal dosing did not enhance brain delivery. This is in contrast to other reports of large molecular weight substances and metals gaining direct access to the brain through the nasal epithelium.

Administration, Intranasal↗

PubMed1997

Perforin-enhancing protein, a low molecular weight protein of cytotoxic lymphocyte granules, enhances perforin lysis.

Perforin is a 68 kD protein found in the granules of cytotoxic lymphocytes and is used by lymphocytes to form lethal pores in the membranes of the cells they kill. We and others have found that when perforin is purified, its lytic activity is markedly reduced. ELISAs indicated that our final recovery of perforin protein was excellent. We decided to determine if depletion of other granule proteins contributed to the loss of lytic activity. We isolated perforin to the point where lytic activity was diminished and added back granule proteins that had no lytic activity or detectable (antigenic) perforin. Perforin was isolated by Cu2+-immobilized metal affinity chromatography (IMAC) followed by phenyl-Superose hydrophobic interaction chromatography (HIC). Its lytic activity was enhanced by a low molecular weight (<15 kD) protein, perforin enhancing protein (PEPr). We have isolated PEPr by two methods, HIC and MonoQ. Nonlytic PEPr restored perforin to close to its original lytic activity. A protein similar if not identical to PEPr was also detectable as an 125I-labeled protein associated with lytic perforin. We propose that PEPr acts in conjunction with perforin to form lethal pores and suggest that PEPr may be the rat equivalent of the human cytotoxic lymphocyte protein, granulysin.

Animals↗

PubMed2001

Enhanced fusion of a nucleopolyhedrovirus with cultured cells by a virus enhancing factor from an entomopoxvirus.

Fusion of Pseudaletia unipuncta nucleopolyhedrovirus with an armyworm cell line (SIE-MSH-805-F) was studied by means of three fluorescence assays that are based on the relief of fluorescence self-quenching of octadecylrhodamine B chloride (R18). A gradual increase in fluorescence intensity indicative of virus-cell fusion was observed by spectrofluorometry when R18-labeled polyhedron-derived virus was incubated with cultured cells. The fusion was enhanced by the virus enhancing factor (EF) from Pseudaletia separata entomopoxvirus. Lysosomotropic agents had little effect on the virus-cell fusion. The percentage of positively fluorescent cells, as determined by flow cytometry, gradually increased after the addition of labeled virus and was higher in the presence of the EF than in its absence. Confocal microscopy of cultured cells that had been combined with labeled virus showed that the fluorescence appeared first on their surface. The plasma membrane of cultured cells had specific affinity to the EF, as revealed by indirect immunofluorescence microscopy.

Animals↗

PubMed1993

Vitamin A potentiation of carbon tetrachloride hepatotoxicity: enhanced lipid peroxidation without enhanced biotransformation.

To better understand the mechanism by which vitamin A (VA, retinol) potentiates the hepatotoxicity of carbon tetrachloride, its effect on metabolism and covalent binding of CCl4 as well as its effect on lipid peroxidation was determined. 14CCl4 (0.15 ml/kg, 21.4 microCi/mmol) was administered to male SD rats that had been treated with vitamin A (250,000 IU/kg/day for 1 week) or vehicle. Vitamin A pretreatment did not increase the 24-hr biotransformation of 14CCl4 to 14CO2, to exhaled volatile organics, or to metabolites excreted in the urine or feces. Furthermore, there was no dramatic effect of vitamin A pretreatment on the covalent binding of 14CCl4 equivalents to hepatic lipids and proteins at early time points (1/2-4 hr) after administration of 14CCl4. The microsomal concentration of cytochrome P450 was unchanged by vitamin A treatment. There was a dramatic increase (6-8x) in the amount of ethane exhaled in those rats treated with vitamin A and then administered CCl4 compared to that of those administered CCl4 without pretreatment. The enhanced lipid peroxidation as evidenced by the increased exhalation of ethane was not the result of vitamin A-induced decreases in hepatic glutathione or vitamin E. These data indicate that the potentiation of CCl4 hepatotoxicity by vitamin A pretreatment is associated with an enhancement of lipid peroxidation that is independent of changes in CCl4 biotransformation or the hepatic concentration of two important hepatoprotective agents.

Animals↗

PubMed1995

Murine leukemia virus-induced neurodegeneration of rats: enhancement of neuropathogenicity correlates with enhanced viral tropism for macrophages, microglia, and brain vascular cells.

A highly neuropathogenic retrovirus, NT40, was generated by serially passaging an infectious molecular clone of Friend murine leukemia virus, FB29, through F344 Fisher rats. NT40 induced severe neurological signs such as reflex abnormalities and ataxia within 4-6 weeks following neonatal inoculation. FB29 led to only very mild neurological dysfunctions with longer incubation periods. Pathological alterations were characterized by mild (FB29) to extensive (NT40) noninflammatory spongiform degeneration, mainly of brain-stem areas. Infectious center assays revealed that viral titers in brain tissues of NT40-infected rats were 100-fold higher than those of FB29-infected animals. Employing immunohistochemistry, in situ hybridization, and flow cytometry, NT40 was found to infect many endothelial cells of brain blood vessels and microglia, whereas FB29 infected only microglia and those to a lower extent. However, when isolated from adult diseased rats, microglial cells turned out in both cases to be nonproductively infected with either FB29 or NT40. Of peripheral organs, we found enhanced levels of NT40 in peritoneal macrophages but not in spleen, thymus, or serum when compared to FB29. Altogether these data suggest that an expanded cellular tropism within the CNS and elevated viral titers in macrophages and microglia correlated with enhancement of neuropathogenicity.

3T3 Cells↗

PubMed1997

Asymmetrical or heterogeneous enhancement of the internal jugular veins in contrast-enhanced CT of the head and neck.

With faster CT scanners, asymmetric/heterogeneous enhancement (ASHE) of the internal jugular veins (IJVs) is frequently encountered in the absence of pathology. We investigated the frequency, side, pattern and significance of ASHE in 200 patients with various head and neck lesions. Non-ionic contrast medium (300 mgI/ml) was infused into a forearm vein (right, n = 100); left, n = 100). Forty seconds after contrast medium injection, contiguous 5-mm-thick sections were obtained craniocaudally from the skull base to the aortic arch. CT machines with two different scanning cycle times (3 s, n = 100; 2 s, n = 100) were used. ASHE of the IJVs was observed in 51 patients (25.5%); the patient group receiving a right-sided injection with a 2-s scan cycle machine, showing a higher frequency (44%). ASHE was divided into four patterns: homogeneous low density, focal low density, heterogenous opacification and fluid-fluid level formation. ASHE was frequently observed in routine contrast-enhanced CT of the head and neck. Frequency of ASHE increased when the scanning cycle was shorter. We should be aware of this phenomenon to avoid its misinterpretation as venous thrombosis or other pathology.

Adolescent↗

PubMed2003

Kirner's deformity of all fingers in a 5-year-old girl: soft-tissue enhancement with normal bones on contrast-enhanced MRI.

Kirner's deformity is an uncommon, but characteristic volar-radial incurvature of the distal phalanx of the little finger. We report a 5-year-old girl with dystelephalangy of all fingers. Some members of the mother's family showed dystelephalangy of the little fingers; the father's family history was unaffected. Contrast-enhanced MRI showed enhancement of the soft tissues of the distal phalanges, but no bone deformities. This leads to the assumption that the radial and volar deviation of the distal phalanges is the result of a chronic inflammatory process or a vascularisation disorder of the soft tissue.

Child, Preschool↗

PubMed2002

Pediatric excretory MR urography: comparative study of enhanced and non-enhanced techniques.

Our purpose was to compare the quality of ureteral imaging in pediatric patients using two different MR sequences: the non-enhanced heavily T2-weighted (W) turbo spin-echo sequence (TSE) and the gadolinium-enhanced T1W fast-field-echo sequence (T1 FFE). An experimental study on three pigs was first performed. The TSE, before and after furosemide injection, was followed by the T1 FFE sequence. The clinical study included 11 infants and 10 children. With some modifications the same MR parameters and techniques were used as in the animal study. The TSE with TR 8000 ms and TE 650 ms implied 6 radial stacks each of 40 mm thickness. The T1 FFE included TR 18 ms, TE 2.9 ms, flip angle 60, and 50 slices with thickness 0.7 mm. After post-processing, image reconstructions qualitative and quantitative analysis were performed. Complete visualization of the ureters was achieved in 35 of 42 (83%) cases. Seventy-four percent of the ureters were completely visualized with T1 FFE compared with only 19% with TSE. Sixty-nine percent of the ureters were better imaged with T1 FFE than TSE and 21% equally well imaged. Four ureters (10%), either obstructed or due to poor renal function, were better imaged with TSE. The two sequences are complementary. Visualization of non-obstructed ureters is excellent with T1 FFE and the sequence is superior to TSE. The TSE, however, may be equal to or even better than T1 FFE in visualizing obstructed ureters or ureters draining malfunctioning kidneys.

Animals↗

PubMed2006

Contrast-enhanced ultrasonography to detect liver metastases : a prospective trial to compare transcutaneous unenhanced and contrast-enhanced ultrasonography in patients undergoing laparotomy.

BACKGROUND/AIMS: The advent of contrast-enhanced ultrasound (CEUS) has called into question the efficacy of standard ultrasonographic techniques. In this study, we evaluated B-mode and color-duplex imaging and CEUS in the detection of liver metastases, using intraoperative and histological findings as a reference. MATERIALS AND METHODS: Before laparotomy, 108 patients suspected of having liver metastases were prospectively examined with B-mode and color-duplex imaging, followed by contrast-enhanced ultrasound (2.4 ml SonoVue). Patients with unresectable tumors (n=8) were excluded from the analysis. The sonographic diagnosis in the remaining 100 patients was compared to the intraoperative and histological findings. RESULTS/FINDINGS: CEUS improved the sensitivity for detecting liver lesions from 56.3% (B-mode) to 83.8% (CEUS) (p=0.004). In particular, the contrast agent led to an improvement in ultrasonographic detection in the following cases: nodular metastases smaller than one centimeter; after adjuvant chemotherapy; for tumors near the surface of the liver; and for lesions situated around the ligamentum teres. INTERPRETATION/CONCLUSIONS: CEUS provides significant improvement in the detection of liver metastases, and should therefore, be performed routinely in the surveillance of cancer patients.

Adult↗

PubMedDate not supplied

Delayed contrast enhancement in a patient with perimyocarditis on contrast-enhanced cardiac MRI: case report.

The findings of contrast-enhanced cardiac magnetic resonance imaging of a 19-year-old man with perimyocarditis in the subacute and chronic stage are presented. In perimyocarditis., it is useful to check the presence of delayed contrast enhancement to confirm the presence of the lesion and to evaluate the severity of inflammation in the acute stage as well as to determine the extent of fibrosis in the pericardium and myocardium in the chronic stage.

Acute Disease↗

PubMed1990

Enhanced proliferation of murine T cell lines following interaction of poly(Glu60,Phe40) (GPhe) and antigen-presenting accessory cells. I. GPhe-stimulated enhancement of antigen-dependent proliferative responses.

Following interaction of the random polymer (Glu60,Phe40)n (GPhe) with antigen-presenting accessory cells (APC), unusual costimulatory activities were noted in several murine T cell systems. When GPhe, in contrast with other random copolymers (GT,GL), was added during "inhibition" and T cell "repertoire" studies as a (negative) control to GLA-reactive nonclonal T cell lines of haplotypes H-2d (DCL-2) or H-2bm12, augmentation of T cell proliferation ([3H]thymidine incorporation ([3HT]) to homologous antigen was observed. Augmentation by GPhe was also observed in the response of a GLPhe-reactive (H-2s X H-2d)F1 T cell line and the allogeneic response of the clonal T cell line D10.G4.1. This augmentation was critically dependent on the concentration of adherent accessory cells. Although the mechanism of action of GPhe remains, as yet, undefined, the GPhe-mediated enhancement of DCL-2 (a TH2, H-2d anti-GLA, T cell line) proliferation was not dependent upon the production of either IL-1 or IL-6 by accessory cells. In addition, enhanced DCL-2 proliferation was not accompanied by a significant increase in detectable IL-4 release.

Animals↗

PubMed1984

Heat-enhanced reactivation of UV-irradiated adenovirus 2 is not associated with enhanced mutagenesis in HeLa cells.

The reversion frequency of an adenovirus 2 temperature-sensitive growth mutant irradiated with different doses of UV light was determined after infection of control, UV-irradiated and heat-shocked HeLa cells. No enhancement of mutagenesis by treatment of the cells was observed. Heat-enhanced viral reactivation does not therefore display a significant error-prone component.

Adenoviruses, Human↗

PubMed1987

Enhanced reactivation of UV-irradiated adenovirus 2 is not associated with enhanced mutagenesis in carcinogen-pretreated HeLa cells.

Treatment of HeLa cells with low doses of the carcinogens aflatoxin B1, methyl methanesulfonate (MMS) or ethyl methanesulfonate (EMS) increases the survival rate of UV-irradiated adenovirus 2 (ade2). This increase is maximal if the time interval between cell treatment and virus infection is delayed by 36 h. No enhanced mutagenesis was found measuring the reversion frequency of a temperature-sensitive mutant of ade2 grown in HeLa cells treated with the same carcinogens. The enhanced viral reactivation observed does not, therefore, display a significant error-prone component.

Adenoviruses, Human↗

PubMed2005

Comparison of ezetimibe plus simvastatin versus simvastatin monotherapy on atherosclerosis progression in familial hypercholesterolemia. Design and rationale of the Ezetimibe and Simvastatin in Hypercholesterolemia Enhances Atherosclerosis Regression (ENHANCE) trial.

BACKGROUND: Lipid lowering through statin therapy significantly reduces the risk of cardiovascular events. The ENHANCE study is an international 2-year, randomized, double-blind, controlled trial designed to test the hypothesis that treatment of hypercholesterolemia by use of 2 complementary agents, ezetimibe (a specific cholesterol absorption inhibitor) and simvastatin (a 3-hydroxy-3-methylglutaryl coenzyme A reductase inhibitor), will result in larger beneficial effects on carotid artery intima-media thickness (CA IMT) than simvastatin monotherapy. METHODS: The study will recruit 725 men and women with heterozygous familial hypercholesterolemia. After a placebo washout period, participants are randomized to receive daily administration of either simvastatin 80 mg and ezetimibe 10 mg or simvastatin 80 mg and placebo. The ENHANCE trial uses novel state-of-the-art single-frame digital image acquisition and rigorous quality assurance and control. RESULTS: The primary end point is mean change from baseline to 2 years in CA IMT, using composite measures from the right and left far wall common carotid artery, carotid bulb, and internal carotid artery. Secondary end points include (1) the proportion of participants who exhibit reductions in CA IMT, (2) the change in maximum far wall IMT, (3) the proportion of participants who develop new carotid artery plaques, and (4) the changes in carotid plus common femoral artery IMT. CONCLUSIONS: This study addresses the question of whether a regimen that uses drugs with different mechanisms of action will be of further benefit in terms of atherosclerosis reduction compared to statin monotherapy.

Adult↗

PubMed2005

Enhanced photodynamic activity of hypericin by penetration enhancer N-methyl pyrrolidone formulations in the chick chorioallantoic membrane model.

Hypericin (HY) was examined for photodynamic therapy (PDT)-induced vascular damage using the chick chorioallantoic membrane (CAM) model. Clinically, plasma protein was used to solubilize HY. Upon binding to albumin, free HY available to be transported through the membrane may be limited. Hence, formulations containing a biocompatible solvent, N-Methyl pyrrolidone (NMP), have the potential to enhance HY delivery into solid tumors. At suitable concentrations, NMP and/or light irradiation did not produce antivascular damage. Hypericin-PDT effects showed to be HY and NMP concentrations-dependent. These findings indicate that NMP is a promising solvent and penetration enhancer for HY-PDT clinical applications.

Animals↗

PubMed2003

Enhanced expression of lymphotactin by CD8+ T cells is selectively induced by enhancer agonist peptides of tumor-associated antigens.

Human tumor-associated antigens (TAAs) are weak immunogens. One strategy for increasing the immunogenicity of TAAs is to generate altered peptide ligands. In the studies reported here, microarray technology has been used to compare gene expression profiles of a human T cell line that was derived from the peripheral blood of a cancer patient vaccinated with a carcinoembryonic antigen (CEA)-based vaccine. We compared the gene expression profiles of this CEA-specific CD8 T cell line when (a) stimulated with the native peptide used to derive this line vs. no peptide, and (b) stimulated with its TCR enhancer agonist epitope vs. no peptide. The results demonstrate that the effect on the T cell line, when stimulated with the agonist peptide, is not an enhanced quantitative expression of the same genes or gene sets induced by the native peptide, but is rather a nearly reciprocal upregulation of different gene sets. The gene for the chemokine lymphotactin, which was overexpressed only in T cells stimulated with the agonist peptide, stood out above all others. This finding was extended using other T cell lines, and another set of agonist and native peptides from another TAA. ELISPOT and ELISA assays for lymphotactin confirmed and extended these findings. These studies suggest a potential role for lymphotactin in the T-cell activation processes and subsequent anti-tumor events.

Animals↗

PubMed2005

FK962, a novel enhancer of somatostatin release, exerts cognitive-enhancing actions in rats.

FK962 (N-(1-acetylpiperidin-4-yl)-4-fluorobenzamide) is a derivative of FK960 (N-(4-acetyl-1-piperazinyl)-p-fluorobenzamide monohydrate), with putative anti-dementia properties. Here, we wanted to determine whether FK962 retained the ability of the parent compound to both facilitate somatostatinergic nerve activity in hippocampal neurons and to ameliorate cognitive dysfunction in rat models. FK962 (10(-9) - 10(- 6) M) significantly enhanced high K+-evoked somatostatin release from rat hippocampal slices. FK962 also significantly reduced somatostatin-induced inhibition of Ca2+ channels at 10(-9) - 10(-7) M in single rat hippocampal neurons using whole-cell patch-clamp. Furthermore, administration of FK962 (0.032-3.2 mg/kg, i.p.) significantly ameliorated memory deficits in passive avoidance task in animal models: scopolamine-treated rats, nucleus basalis magnocellularis-lesioned rats and aged rats. FK962 (0.01- 1) mg/kg, i.p.) significantly improved spatial memory deficits induced by nucleus basalis magnocellularis-lesion in water maze task. These results suggest that FK962 ameliorates cognitive impairment in rats via activation of the somatostatinergic nervous system in the hippocampus, indicating that FK962 could be a potent cognitive enhancer and therefore might be of therapeutic value for cognitive disorders such as Alzheimer's disease.

Aging↗

PubMed2005

HIV-1 Cis Enhancing Sequence (CES) enhances CTE-dependent Gag expression.

In order to export intron-containing RNA from nucleus, retroviruses use either viral trans-acting factors or constitutive cellular factors interacting with cis-elements in their intron-containing RNA. We have previously identified a Cis Enhancing Sequence (CES) in HIV-1 env region that could co-operate with Rev and RRE to enhance Gag expression by promoting RNA stabilization and exportation. In this study, we found that CES could function in a Rev-independent manner by co-operating with a Constitutive Transport Element (CTE) of Mason-Pfizer monkey viruses (MPMV). RRE and CTE promote intron-containing RNA exportation through different pathways. The fact that CES could function in both pathways of RNA export suggested that CES might function at a common step either up- or downstream to Rev/RRE or CTE functions. Known hnRNP-A1-binding sites as well as other 3 highly conserved sequences in the CES were found to be required for its activity.

Animals↗