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At least 505 records · Page 28Linked to original sources

PubMed2003

Comparison of contrast-enhanced ct angiography and gadolinium-enhanced MR angiography in the detection of subsegmental-sized pulmonary embolism. An experimental study in a pig model.

PURPOSE: To compare contrast-enhanced CT angiography (CTA) and gadolinium-enhanced MR angiography (MRA) for the detection of subsegmental-sized pulmonary emboli in a pig model. MATERIAL AND METHODS: In 5 anesthetized pigs, 3-mm diameter embolic materials made of Konjac, a semisolid food, were introduced through the internal jugular vein into pulmonary arteries. After embolization, CTA and MRA images were obtained. Respiration was suspended during CTA and MRA image acquisition. Two readers reviewed the CTA and MRA images to detect emboli. The pigs were sacrificed, and sliced specimens of inflated lung served as the gold standard. RESULTS: Thirty-six emboli were detected within peripheral arteries. The sensitivity (and 95% confidence intervals) of CTA for the two readers were 57% (39-74%) and 66% (48-81%), and 88% (69-98%) and 92% (74-94%) for MRA. The specificity of CTA was 95% (91-97%) and 98% (96-99%), and that of MRA was 85% (74-93%) and 90% (80-96%). Interobserver agreement was higher for MRA (kappa 0.898) than CTA (kappa 0.574). CONCLUSION: For the detection of subsegmental pulmonary emboli, MRA was superior to CTA, with a higher sensitivity and interobserver agreement by demonstrating perfusion deficits.

Animals↗

PubMed1974

Specific heterologous enhancement of immune responses. VI. Partial purification of a nonspecific enhancing factor from supernates of allogeneically stimulated human lymphocyte cell lines.

The mixing of two histoincompatible human lymphocyte cell lines generated the release of a soluble factor which was capable of nonspecifically enhancing the in vitro immune response of normal mouse spleen cells against sheep erythrocytes. When active supernates were subjected to exclusion chromatography on Sephadex G-150 and BioGel P-150, the active principle eluted with molecules of approximately 35,000 mol wt. Column aliquots from similarly treated supernates from independent cultures of each lymphoid cell line were inactive. The human enhancing factor was concentrated and purified by ammonium sulfate fractionation, followed by Sephadex gel filtration and polyacrylamide gel electrophoresis.

Animals↗

PubMed1974

Quantitative studies on tumor enhancement in mice. I. Enhancement of sarcoma I induced by IgM, IgG1, and IgG2.

The concentration of specific alloantibody in purified mouse immunoglobulin preparations was determined. When passively transferred in adequate doses, IgM, IgG1, and IgG2 antibodies all induced tumor enhancement in allogeneic hosts. IgM and IgG2 antibodies in high concentration led to inhibition of tumor growth. IgM and either IgG1 or IgG2 had additive effects on tumor enhancement. IgG1, but not IgG2, suppressed the inhibitory effect of IgM in high concentration.

Animals↗

PubMed1977

Enhancement of 5-iododeoxyuridine-induced endogenous C-type virus activation by polycyclic hydrocarbons: apparent lack of parallelism between enhancement and carcinogenicity.

When mouse MLg cells were treated with 3-methylcholanthrene or 7,12-dimethylbenz[alpha]anthracene in the presence of microsomal enzymes and NADPH after 5-iododeoxyuridine (IUDR) treatment, the induction rate of the endogenous C-type virus was increased fivefold to sixfold in comparison with the culture treated with IUDR only. In this reaction, both the microsomal enzymes and NADPH were indispensable. 7,8-Benzoflavone, an inhibitor of the metabolism of hydrocarbons in hamster embryo cultures, inhibited the reaction. For detecting the enhancing activity, the concentration of IUDR for the pretreatment, the concentration of the test products, and the duration of the treatment with the products were important factors. In screening 30 polycyclic hydrocarbons, we were unable to detect a correlation between the in vivo carcinogenicity in the skin and the enhancing activity in the conditions tested.

9,10-Dimethyl-1,2-benzanthracene↗

PubMedDate not supplied

Comparison of contrast-enhanced magnetization transfer imaging and contrast-enhanced fat saturation T1-weighted imaging in nasopharyngeal carcinoma.

OBJECTIVE: The objective of this study was to evaluate the efficacy of contrast-enhanced magnetization transfer (CEMT) imaging in the study of nasopharyngeal carcinoma (NPC). METHODS: The contrast-to-noise ratio (CNR) of CEMT images was compared with the CNR of contrast-enhanced fat-saturation (CEFS) T1-weighted images in locoregional tumors and adenopathies of 50 patients with pathologically proven NPC. RESULTS: The CEMT images showed higher CNRs than CEFS images of local nasopharyngeal regions. The mean CNRs of the precontrast T1-weighted, CEFS, and CEMT images were 4.9, 15.4, and 21.2, respectively. There was a statistically significant difference (p < 0.01) in the CNRs of CEFS and CEMT images. In considering images of nodal metastasis, the mean values in these three groups were 0.7, 16.8, and 19.7, respectively, with the difference (p < 0.05) between CEFS and CEMT being statistically significant. CONCLUSIONS: The CEMT image with a larger CNR is superior to the CEFS image in detecting locoregional NPC. CEMT can be useful in imaging patients with possible small tumors and local recurrences.

Adolescent↗

PubMed2000

Enhanced allograft survival induced by posttransplant donor spleen cell infusion occurs via a mechanism that is distinct from the mechanism of enhancement by donor bone marrow.

BACKGROUND: Our previous studies have shown that the ability of donor bone marrow to augment skin graft survival in antithymocyte serum (ATS)-treated recipients is dependent on the presence of functional CD95-ligand (Fas-ligand) molecules on donor cells. Because donor spleen cells can augment graft survival to a similar degree in the same model, we investigated whether the donor spleen cell effect was also dependent on the presence of CD95-ligand on donor cells and CD95 on recipient cells. METHODS: Mutant mice bearing defects in the expression of CD95 (lpr mutation) and CD95-ligand (gld mutation) were used as recipients and cell donors, respectively. Recipients were injected with rabbit ATS on days -1 and +2, and then were injected with 5x10(7) spleen cells on day +7. Skin graft survival was compared and correlated with the use of mutant mice as recipients and cell donors. RESULTS: The combination of ATS and infusions of wild-type [median survival (MST)=44 days, P=0.0004] and gld (mutant CD95-ligand, MST=37 days, P=0.02) donor spleen cells enhanced C3H graft survival, compared with (C57BL/6 x A)F1 recipients treated with ATS alone (MST=27 days). Furthermore, C57BL/6 lpr (CD95-deficient) strain recipients treated with ATS and donor spleen cells demonstrated enhanced B10.D2(R107) strain skin graft survival (MST=44 days, P=0.003), compared with C57BL/6 lpr recipients treated with ATS alone (MST=31 days). Wild-type C57BL/6 recipients treated in the same manner also exhibited an extension of graft survival (MST=64 days) versus controls treated with ATS alone (MST=31 days). CONCLUSION: The data demonstrate that the ability of donor spleen cells to augment allograft survival is not dependent on the CD95/CD95-ligand pathway; therefore the deletion of allospecific cells by donor spleen cells may be induced via a pathway other than deletion by donor bone marrow cells.

Animals↗

PubMedDate not supplied

The Enhancing Recovery in Coronary Heart Disease Trial (ENRICHD): strategies and techniques for enhancing retention of patients with acute myocardial infarction and depression or social isolation.

The report aims to review the literature and describe the methods used for retention of patients in a clinical study. The Enhanced Recovery in Coronary Heart Disease (ENRICHD) trial was a multicenter, randomized clinical trial designed to evaluate the effects of a psychosocial intervention on cardiovascular morbidity and mortality. A total of 2481 patients met the criteria for depression, low social support, or both after a myocardial infarction and needed to be followed. Follow-up evaluation consisted of telephone interviews 3, 9, 12, 24, 36, and 48 months after enrollment and clinic visits scheduled at 6, 18, 30, 42, and 54 months. Creative strategies used to achieve optimum retention of this complex patient population over a long follow-up period are presented. Strategies to enhance adherence throughout the course of the trial required adequate tracking of patients to ensure minimum dropout, follow-up evaluation optimized through multiple methods of contact to guarantee completeness of data collection; and development of procedures to address the needs of patients at risk for dropout. Patients in the group that completed the study participated for a mean of 28.3 months, and those lost to follow-up evaluation participated for a mean of 19 months. Retention was not substantially different by gender or minority status. The results of this project can assist investigators in planning studies that require patient follow-up evaluation, and can provide clinicians with specific strategies for maximizing retention-to-treatment recommendations. As a result of the retention strategies described in this report, 93.02% of the patients completed their study participation or died. This is a very high retention rate given the complexity of the study sample, protocol, and required duration of follow-up evaluation.

Adult↗

PubMed2000

Strongly enhanced magnetic excitations near the quantum critical point of Cr1-xVx and why strong exchange enhancement need not imply heavy fermion behavior.

Inelastic neutron scattering reveals strong spin fluctuations with energies as high as 0.4 eV in the nearly antiferromagnetic metal Cr0. 95V0.05. The magnetic response is well described by a modified Millis-Monien-Pines function. From the low-energy response, we deduce a large exchange enhancement, more than an order of magnitude larger than the corresponding enhancement of the low-temperature electronic heat capacity gammaT. A scaling relationship between gamma and the inverse of the wave vector-averaged spin relaxation rate gammaave is demonstrated for a number of magnetically correlated metals.

Journal Article↗

PubMed1997

Arabidopsis enhanced disease susceptibility mutants exhibit enhanced susceptibility to several bacterial pathogens and alterations in PR-1 gene expression.

To identify plant defense responses that limit pathogen attack, Arabidopsis eds mutants that exhibit enhanced disease susceptibility to the virulent bacterial pathogen Pseudomonas syringae pv maculicola ES4326 were previously identified. In this study, we show that each of four eds mutants (eds5-1, eds6-1, eds7-1, and eds9-1) has a distinguishable phenotype with respect to the degree of susceptibility to a panel of bacterial phytopathogens and the ability to activate pathogenesis-related PR-1 gene expression after pathogen attack. None of the four eds mutants exhibited observable defects in mounting a hypersensitive response. Although all four eds mutants were also capable of mounting a systemic acquired resistance response, enhanced growth of P. s. maculicola ES4326 was still apparent in the secondarily infected leaves of three of the eds mutants. These data indicate that eds genes define a diverse set of previously unknown defense responses that affect resistance to virulent pathogens.

Arabidopsis↗

PubMed1994

Envelope glycoprotein (gp120) from HIV-1 enhances Mycobacterium avium growth in human bronchoalveolar macrophages; an effect mediated by enhanced prostaglandin synthesis.

Human bronchoalveolar lavage (BAL) macrophages were obtained from normal human volunteers and infected with an AIDS-associated strain of Mycobacterium avium. Infected cells were exposed to purified envelope glycoprotein (gp120) from HIV-1 or to the recombinant non-glycosylated gp120 fragments PBI-RF and PBI-IIIB. Native gp120 increased Myco. avium growth in human cells from six separate donors, whereas the non-glycosylated fragments of gp120 had no such effect. Moreover, gp120 induced a substantial secretion of prostaglandin E2 (PGE2) from macrophages; inclusion of indomethacin blocked the enhanced permissiveness of infected cells treated with gp120. Soluble CD4 also neutralized the effect of gp120. Overall, these results indicate a role for gp120 in the susceptibility of AIDS patients to Myco. avium infections, mediated by an enhanced PGE2 release.

Bronchoalveolar Lavage Fluid↗

PubMed1990

Substance P enhances desensitization of the nicotinic response in bovine chromaffin cells but enhances secretion upon removal.

A fundamental process in neurosecretion is desensitization, or a declining response to a stimulus. The response of chromaffin cells to continuous nicotinic stimulation, secretion of catecholamines, desensitizes within a few minutes. The neuropeptide substance P (SP) has been reported to prevent desensitization in culture dish experiments and to enhance desensitization in patch clamp studies. In the present study, these contradictory responses have been demonstrated and the apparent contradictions resolved. We have measured catecholamine secretion by on-line electrochemical detection in a constant-pressure flow system. Isolated chromaffin cells cultured on quartz plates were stimulated with the nicotinic agonist 1,1-dimethyl-4-phenylpiperazinium (DMPP) in the presence and absence of SP. SP inhibited secretion and increase the rate of desensitization compared with stimulation by DMPP alone. However, when the cells were stimulated a second time with DMPP alone immediately after 5-min stimulation with SP + DMPP, the rate of desensitization was markedly lower than the control. Removal of SP after a desensitizing stimulation with SP + DMPP caused a slow secondary release of catecholamine in response to the continued stimulation with DMPP. The kinetic analysis of the secretory response shows that the primary response to SP is enhanced desensitization, but that upon removal of SP the response to DMPP desensitizes less rapidly. We suggest that SP protects some receptors from nicotinic desensitization while holding them in an inactive state, and that upon removal of SP these receptors can slowly respond to DMPP.

Animals↗

PubMed1990

Enhanced Growth of Wheat and Soybean Plants Inoculated with Azospirillum brasilense Is Not Necessarily Due to General Enhancement of Mineral Uptake.

The capacity of Azospirillum brasilense to enhance the accumulation of K, P, Ca, Mg, S, Na, Mn, Fe, B, Cu, and Zn in inoculated wheat and soybean plants was evaluated by using two different analytical methods with five A. brasilense strains originating from four distinct geographical regions. A Pseudomonas isolate from the rhizosphere of Zea mays seedlings was included as a control. All A. brasilense strains significantly improved wheat and soybean growth by increasing root and shoot dry weight and root surface area. The degree of plant response to inoculation varied among the different strains of A. brasilense. All strains were capable of colonizing roots, but the best root colonizer, Pseudomonas sp., had no effect on plant growth. The numbers of organisms of Brazilian strains Sp-245 and Sp-246 colonizing roots were similar regardless of the host plant. Numbers of organisms for the other strains were directly dependent on the host plant. The main feature characterizing mineral accumulation in inoculated plants was that all inoculation treatments changed the mineral balance of the plants, but in an inconsistent manner. Enhancement of mineral uptake by plants also varied among strains to a great extent and was directly dependent on the strain-plant combination; i.e., a strain capable of increasing accumulation of a particular ion in one plant species or cultivar often lacked the ability to do so in another. Minerals in inoculated plants were not evenly distributed in different plant tissues, and the changes varied among groups of plants within each bacterial strain inoculation treatment. We suggest that, although A. brasilense strains are capable of changing the mineral balance and content of plants, it is unlikely that this ability is a general mechanism responsible for plant improvement by A. brasilense.

Journal Article↗

PubMed1981

Trypsin enhancement of rotavirus infectivity: mechanism of enhancement.

The infectivity of most rotaviruses is enhanced by treatment with trypsin. We studied the mechanism of enhancement of examining the effect of trypsin on rotavirus infectivity, aggregation, early interactions with host cells, and structure. The results indicated that trypsin does not increase levels of infectious virus by dispersion of aggregates or affect the efficiency or rate of attachment of virus to cells. A fraction of virus that was not infections without trypsin treatment was found to attach to cells, but did not initiate antigen synthesis. When cells were infected with labeled, purified virus, increased levels of uncoated particles were found in cells infected with trypsin-treated virus. Infection of cells with trypsin-treated virus also led to greater levels of RNA synthesis early in the infection. The results suggest that trypsin converts a noninfectious fraction of virus into infectious virus by allowing this fraction to uncoat in the infected cell. Trypsin was found to cleave an 88,000-dalton structural polypeptide of bovine rotavirus generating 67,000- and 20,000-dalton cleavage products.

Animals↗

PubMed1984

Enhanced reactivation and enhanced mutagenesis of herpes simplex virus in normal human and xeroderma pigmentosum cells.

Enhanced reactivation (ER) and enhanced mutagenesis (EM) of herpes simplex virus type 1 were studied simultaneously in UV-irradiated stationary cultures of diploid normal human and xeroderma pigmentosum (XP) fibroblasts. Mutagenesis was assayed with unirradiated herpes simplex virus type 1 as a probe in a forward mutation assay (resistance to iododeoxycytidine). Dose-response studies showed that ER increased with the UV dose given to the virus. Optimal reactivation levels were obtained when normal cells and XP variant cells were exposed to a UV dose of 8 J . m-2 and the virus was irradiated with 150 J . m-2. Repair-deficient XP cells of complementation groups A, C, and D showed optimal reactivation levels with a UV dose to the cells of 1.0 J . m-2 and a UV dose to the virus of 40 J . m-2. The time course of appearance of ER and EM was also studied, both in the normal and XP cells. In all cell types except the XP variant cells, EM followed similar kinetics of appearance as did ER. Maximal activities occurred when infection was delayed 1 or 2 days after cell treatment. In XP variant cells, however, maximal expression of the EM function was significantly delayed with respect to ER. The results indicate that ER and EM are transiently expressed in normal and repair-deficient XP cells. Although both phenomena may be triggered by the same cellular event, ER and EM appear to be separate processes that occur independently of each other.

Cell Transformation, Viral↗

PubMed2000

Primary diffuse leptomeningeal gliomatosis: unusual MRI with non-enhancing nodular lesions on the cerebellar surface and spinal leptomeningeal enhancement.

A 28 year old man presented with a 1 month history of symptoms of intracranial hypertension. Examination showed bilateral papilloedema and meningeal signs. Magnetic resonance imaging showed nodular lesions on the cerebellar and pontine surface and thickening of the thoracic spinal leptomeninges. Throughout the course of the disease, contrast enhancement was detected in the spinal leptomeninges but not intracranially. Primary diffuse leptomeningeal gliomatosis (PDLG) was diagnosed by biopsy and later confirmed on necropsy. The present case is remarkable for the nodular superficial cerebellar lesions and the absence of intracranial contrast enhancement of the leptomeninges.

Adult↗

PubMed2005

Regulation of muscle GLUT4 enhancer factor and myocyte enhancer factor 2 by AMP-activated protein kinase.

As the primary glucose transporter in skeletal muscle, GLUT4 is an important factor in the regulation of blood glucose. We previously reported that stimulation of AMP-activated protein kinase (AMPK) with 5-aminoimidazole-4-carboxamide-1-beta-d-ribofuranoside (AICAR) increased GLUT4 expression in muscle. GLUT4 enhancer factor (GEF) and myocyte enhancer factor 2 (MEF2) have been shown to be important for normal GLUT4 expression because deletion or truncation of the consensus sequences on the promoter causes depressed GLUT4 mRNA expression. This led to the current study to investigate possible roles for GEF and MEF2 in mediating the activation of GLUT4 gene transcription in response to AMPK. Here we show that, although AMPK does not appear to phosphorylate MEF2A, AMPK directly phosphorylates the GEF protein in vitro. MEF2 and GEF are activated in response to AMPK as we observed translocation of both to the nucleus after AICAR treatment. Nuclear MEF2 protein content was increased after 2 h, and GEF protein was increased in the nucleus 1 and 2 h post-AICAR treatment. Last, GEF and MEF2 increase in binding to the GLUT4 promoter within 2 h after AICAR treatment. Thus we conclude that GEF and MEF2 mediate the AMPK-induced increase in transcription of skeletal muscle GLUT4. AMPK can phosphorylate GEF and in response to AICAR, GEF, and MEF2 translocate to the nucleus and have increased binding to the GLUT4 promoter.

AMP-Activated Protein Kinases↗

PubMedDate not supplied

Application of dye-enhanced laser ablation for liver resection. Production of protein sealant on the cut surface of the liver by enhanced thermal energy of low power diode laser.

BACKGROUND: Dye-enhanced laser ablation (DLA) using a low-power diode laser for indocyanine green (ICG)-stained tissue has proven its effectiveness in dye-enhanced laser photocoagulation of retinal vessels or endoscopic surgical mucosectomy. We have applied DLA in hepatectomy and described its histological distinction in comparison with the cavitron ultrasonic surgical aspirator (CUSA). METHODS: A diode laser (UDL-60 Laser unit, Olympus, Tokyo, Japan) with 810 +/- 20 nm wavelength was employed for this study. The ICG dye (Diagnogreen, Daiichi Pharmaceutical, Tokyo, Japan) with a peak absorption wavelength at 800-810 nm was injected topically into the resection plane of the liver. The liver tissue was divided by touching the tip of the diode laser. Three different concentrations of ICG solution such as 2.0, 1.0 and 0.5 mg/ml were tested in the preliminary animal experiment. The use of a low-power diode laser at 10 W with an ICG concentration of 0.5 mg/ml was the appropriate combination for liver resection. In the clinical series, 27 hepatectomies were performed by DLA, and 10 with CUSA. RESULTS: DLA demonstrated smooth cutting and good hemostasis in liver resection. Among the hepatectomy cases given DLA, no postoperative hemorrhage or bile leakage was noted. The postoperative hospital stay was significantly shorter in the DLA than the CUSA group. The cut surface of the liver was sealed microscopically with a layer of protein coagulum. CONCLUSIONS: A layer of protein sealant on the cut surface of the liver contributes to the short postoperative hospital stay when using DLA.

Adult↗

PubMed2002

Relationship of enhanced norepinephrine activity during memory consolidation to enhanced long-term memory in humans.

OBJECTIVE: The purpose of this study was to investigate the effect of enhanced noradrenergic activity on memory consolidation in humans. METHOD: Thirty healthy subjects (21 men and nine women) viewed a series of 12 slides that depicted an emotionally arousing story. Five minutes after viewing the slides, subjects received either intravenous yohimbine or intravenous placebo in a double-blind randomized fashion. Multiple blood samples were drawn for determining plasma free 3-methoxy-4-hydroxyphenylglycol (MHPG). One week later subjects took a surprise memory test for the slides. RESULTS: There was no significant difference in memory score between yohimbine and placebo groups. Linear regression revealed a significant effect of MHPG on memory score for the group as a whole (subjects who had received yohimbine and those who had received placebo) and for the placebo group alone. CONCLUSIONS: These findings strengthen support for the hypothesis that enhanced memory for emotionally arousing events in humans depends critically on postlearning adrenergic modulation.

Adult↗