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 1,333 records · Page 74Linked to original sources

PubMed2004

Contrast-enhanced high-resolution MRI of invasive breast cancer: correlation with histopathologic subtypes.

OBJECTIVE: We sought to determine whether contrast-enhanced MRI could aid in the identification of the histopathologic subtypes of invasive ductal carcinoma. MATERIALS AND METHODS: We evaluated the contrast-enhanced MR images obtained in 62 women with invasive ductal carcinoma of no special type. The presence or absence of three distinct MRI findings-linear enhancement, a serrated border, and delayed rim enhancement-was evaluated. Classification and regression tree analyses were performed to construct the most efficient algorithm for predicting histopathologic subtype on the basis of dynamic MRI features. RESULTS: Histopathologic subtypes of the invasive ductal carcinomas were scirrhous carcinoma in 22 patients, solid tubular carcinoma in 14, and papillotubular carcinoma in 26. A lesion with a serrated border was observed in 28 (45.2%) of the 62 patients. Delayed rim enhancement was seen in 23 (37.1%) and linear enhancement in 20 (32.3%). Scirrhous carcinomas were closely associated with a serrated border (20/22 or 90.9%, p < 0.0001). Delayed rim enhancement was frequently observed in solid tubular carcinomas (12/14 or 85.7%, p < 0.0001) but was not typically seen in scirrhous carcinomas (1/22 or 4.5%, p < 0.0001). Linear enhancement showed relatively high prevalence in papillotubular carcinomas (13/26 or 50%) and low prevalence in solid tubular carcinomas (1/22 or 7%, p < 0.02). Histopathologic subtypes of invasive breast carcinoma of no special type could be correctly identified in 47 (75.8%) of 62 lesions using the diagnostic algorithm generated by the classification and regression tree analyses. CONCLUSION: MRI features showed a close relationship with histopathologic subtypes of invasive ductal carcinoma of no special type. Contrast-enhanced MRI can be a noninvasive diagnostic tool for histopathologic subtypes of invasive breast cancer.

Adult↗

PubMed1988

Enhancement of natural killer cell activity and interferon production by manganese in young mice.

The effect that MnCl2 has on murine splenic natural killer (NK) cell activity was investigated in infant (10 days old), pre-weanling (18 days old) and weanling (24 days old) C57BL/6J mice. A single intraperitoneal injection of 10, 20 or 40 micrograms MnCl2/g body weight caused a significant enhancement in NK activity, as determined by the in vitro 51Cr release assay. Comparable enhancement of NK activity was observed for age-matched mice injected intraperitoneally with polyinosinic polycytidylic acid (Poly I:C). Both MnCl2 and Poly I:C caused elevations in serum interferon levels. Time-course studies revealed that interferon levels returned to normal within 48 hours following injection with either MnCl2 or Poly I:C; however enhanced NK activity persisted for up to 48 hours in Poly I:C-injected mice and 72 hours in MnCl2-injected mice. The administration of rabbit anti-asialo GMl to MnCl2-injected mice completely abrogated the enhanced NK activity. In addition, the injection of rabbit anti-mouse interferon alpha, beta but not gamma completely abrogated the enhanced NK activity. In addition, the injection of rabbit anti-mouse interferon alpha, beta but not gamma completely abrogated the enhancement of NK activity by MnCl2 and to a lesser extent the enhancement of NK activity by Poly I:C. These results indicate that despite low levels of NK activity in pre-weanling mice, MnCl2 is capable of enhancing this activity by 8-9 fold. Furthermore, Mn-enhanced NK activity in these young mice appears to be mediated by the production of interferon alpha, beta.

Animals↗

PubMedDate not supplied

Contrast-enhanced magnetic resonance angiography: dose the test dose bolus represent the main dose bolus accurately?

OBJECTIVE: To determine whether the time-intensity curves acquired by test and main dose contrast injections for MR angiography are similar. MATERIALS AND METHODS: In 11 patients, repeated contrast-enhanced 2D-turbo-FLASH scans with 1-sec interval were obtained. Both test and main dose time intensity curves were acquired from the abdominal aorta, and the parameters of time-intensity curves for the test and main boluses were compared. The parameters used were arterial and venous enhancement times, arterial peak enhancement time, arteriovenous circulation time, enhancement duration and enhancement expansion ratio. RESULTS: Between the main and test boluses, arterial and venous enhancement times and arteriovenous circulation time showed statistically significant correlation (p < 0.01), with correlation coefficients of 0.95, 0.92 and 0.98 respectively. Although the enhancement duration was definitely greater than infusion time, reasonable measurement of the end enhancement point in the main bolus was impossible. CONCLUSION: Only arterial and venous enhancement times and arteriovenous circulation time of the main bolus could be predicted from the test-bolus results. The use of these reliable parameters would lead to improvements in the scan timing method for MR angiography.

Adult↗

PubMed2004

Contrast-enhanced power Doppler sonography in breast lesions: effect on differential diagnosis after mammography and gray scale sonography.

OBJECTIVE: To evaluate the efficacy of contrast-enhanced power Doppler sonography in the differential diagnosis of breast lesions after a mammography-gray scale sonography combination. METHODS: Sixty-eight patients with 69 breast masses underwent power Doppler sonography before and after intravenous injection of a contrast agent. The lesions were diagnosed as "highly suggestive of malignancy" (category 5; n = 32), "suspicious" (category 4; n = 21), and "probably benign" (category 3; n = 16) by mammography and gray scale sonography, modeled on the American College of Radiology Breast Imaging Reporting and Data System classification. Power Doppler findings did not affect patient treatment. The authors subjectively evaluated the estimated area of vascularity, degree of enhancement following contrast agent administration, morphologic features, and distribution of vessels within the lesions. RESULTS: The final diagnoses were malignant in 28 lesions and benign in 41. Significant enhancement after contrast agent injection was detected in both the malignant and benign groups. Only 2 criteria, estimated area of vascularity and degree of enhancement following contrast agent administration, proved to be significant diagnostic determinants for contrast-enhanced power Doppler sonography (P < .001; interobserver agreements, 74.4 and 77.8, respectively). Contrast-enhanced power Doppler sonography provided a higher specificity, positive predictive value, and negative predictive value than power Doppler sonography but a lower sensitivity and negative predictive value than mammography-gray scale sonography. Only in the category 4 lesions could the combination of mammography-gray scale sonography and contrast-enhanced power Doppler sonography accomplish a higher specificity (71%) and positive predictive value (70%) than mammography-gray scale sonography (39% and 53%, respectively). CONCLUSIONS: Power Doppler and contrast-enhanced power Doppler sonography cannot be recommended as confirmatory tests in Breast Imaging Reporting and Data System category 3 and category 5 lesions. Although contrast-enhanced power Doppler sonography may help reduce unnecessary biopsies in Breast Imaging Reporting and Data System category 4 lesions, recommendation of its use has many drawbacks, such as imperfectly established criteria, lack of absolute certainty, and high cost.

Adult↗

PubMed2004

Contrast-enhanced sonography of autoimmune pancreatitis: comparison with pathologic findings.

OBJECTIVE: We evaluated the vascularity of autoimmune pancreatitis lesions on contrast-enhanced harmonic gray scale sonographic images in comparison with the pathologic findings. METHODS: Six patients with autoimmune pancreatitis were examined. All patients held their breath from 20 to 50 seconds after the injection of a contrast agent while the vascularity of the lesion was examined by contrast-enhanced harmonic gray scale sonography (early phase), and lesion enhancement was monitored at about 90 seconds after the injection while the patients held their breath for a few seconds (delayed phase). We then compared the vascularity on the contrast-enhanced harmonic gray scale sonographic images with the pathologic findings (fibrosis and inflammation) in all lesions. The vascularity of 3 of the 6 lesions was also evaluated by contrast-enhanced harmonic gray scale sonography before and after treatment with corticosteroids. RESULTS: The autoimmune pancreatitis lesions exhibited mild (n = 1), moderate (n = 3), or marked (n = 2) enhancement throughout almost the entire lesions in both the early and delayed phases. The grade of lesion vascularity on the contrast-enhanced harmonic gray scale sonographic images correlated with the pathologic grade of inflammation and inversely correlated with the grade of fibrosis associated with autoimmune pancreatitis. The vascularity of all 3 lesions had decreased on the contrast-enhanced harmonic gray scale sonographic images after steroid therapy. CONCLUSIONS: Contrast-enhanced harmonic gray scale sonography may be useful for evaluating the vascularity of autoimmune pancreatitis lesions and the therapeutic efficacy of steroid therapy.

Aged↗

PubMed1976

Differentiation of lymphoid cells: B cell as a direct target and T cell as a regulator in lipopolysaccharide-enhanced induction of immunoglobulin production.

The cells involved in the stimulatory effect of bacterial lipopolysaccharide (LPS) on the induction of immunoglobulin (Ig) production by rabbit spleen cells cultured in the absence of antigen has been analyzed. Addition of LPS caused a several-fold enhancement of both DNA synthesis and Ig production. These enhanced activities were not significantly affected by depletion of adherent cells in the spleen cell population. Although inactivation of splenic T cells by anti-thymocyte serum (ATS) treatment did not affect the enhancement of DNA synthesis due to LPS, such treatment did adversely affect the enhancement of Ig production by LPS. Furthermore, the enhancement of Ig production of ATS-treated spleen cells by LPS was found to be dependent on the number of thymocytes added. In addition, the prior incubation of ATS-treated spleen cells with LPS resulted in effective enhancement of Ig production when such ATS-treated spleen cells and thymocytes were combined after removal of LPS. An identical experiment, except that thymocytes instead of ATS-treated spleen cells received the prior incubation with LPS, did not result in enhancement of Ig production. Finally, the enhanced Ig production due to LPS was inhibited by hydroxyurea, a known inhibitor of cellular DNA synthesis. The relationship between the mitogenic activity of LPS on B cells, the regulatory function of T cells, and the enhancement of Ig production by LPS is discussed in relation to the contrasting reports concerning the cellular target of LPS.

Animals↗

PubMed2001

Antibody-dependent enhancement of heterotypic dengue infections involved in suppression of IFNgamma production.

Antibody-dependent enhancement has been implicated in some outbreaks of epidemic dengue hemorrhagic fever, however, the mechanism of antibody-dependent enhancement is not well known. This study was conducted to investigate the cross-protection and cross-enhancement of dengue-2 virus infections by dengue-1 immune sera. It was found that dengue-1 immune sera at 1:5 dilution (n = 12) could neutralize dengue-2 infections in BHK-21 cells, as assessed by a standard plaque-reduction neutralization assay. Two-thirds of the dengue-1 immune sera at 1:25 dilution demonstrated neutralizing effects for dengue-2 infections, whereas, non-immune sera revealed no neutralization for dengue-2 infections in BHK-21 cells. Human mononuclear leukocytes in response to dengue-2 infections elicited a T cell helper 1 (Th1) response revealing induction of IFNgamma but not IL-4 production. Dengue-1 immune sera did not neutralize dengue-2 infections in mononuclear leukocytes. Subneutralizing titers of dengue-1 immune sera at 1:250, but not at 1:10 dilution, enhanced dengue-2 infections in mononuclear leukocytes (1.2 +/- 0.7 x 10(4) vs. 2.8 +/- 0.3 x 10(2) PFU/ml). The enhancement of dengue-2 infections in mononuclear leukocytes by dengue-1 immune sera at 1:250 was associated with an increase in the lymphocyte proliferation index, and a decrease in IFNgamma production (56 +/- 24 vs. 12 +/- 3 pg/ml). The addition of IFNgamma (0.1 microg/ml) suppressed significantly the antibody-dependent enhancement induced by dengue-1 immune sera, whereas the presence of anti-IFNgamma F(ab)2 antibody augmented the antibody-dependent enhancement effect. Results from this study suggest that suppression of Th1 response may be involved in the antibody-dependent enhancement of heterotypic dengue infections. Better regulation of Th1/Th2 reactions may be useful for prevention of heterotypic immune enhancement of dengue infections.

Antibodies, Viral↗

PubMed1975

Comparative enhancing effects of phenobarbital, amobarbital, diphenylhydantoin, and dichlorodiphenyltrichloroethane on 2-acetylaminofluorene-induced hepatic tumorigenesis in the rat.

Earlier studies showed that phenobarbital feeding enhanced hepatic tumorigenesis in rats previously fed 2-acetylaminofluorene for a brief period. As part of an investigation of the mechanism of this enhancement, the present study evaluated the relative enhancing abilities of amobarbital, diphenylhydantoin, and dichlorodiphenyltrichloroethane (DDT), agents that resemble phenobarbital to varying degrees in their effects on liver structure and metabolism. A comparison of hepatic tumor yields in rats fed 2-acetylaminofluorene, followed by the test substance (sequential treatment), showed that amobarbital and diphenylhydantoin had no enhancing activity, whereas the enhancing effect of DDT was similar to that of phenobarbital. These results show that the sequential treatment technique readily distinguishes among substances differing in enhancing ability and should prove useful in screening additional substances for this activity. The comparative biochemical effects of these substances in the liver can then be correlated with their relative enhancing abilities to provide information on the molecular events specifically associated with enhancement. Such correlations were initiated in this study by comparing the effects of the four test substances on liver weight and DNA synthesis. The results showed that the enhancers, phenobarbital and DDT, each stimulated liver DNA synthesis and increased liver weight, whereas the nonenhancers, amobarbital and diphenylhydantoin, had neither effect. Phenobarbital and DDT both increased the early tumor incidence rate and maintained an increment in tumor incidence over that in the other treatment groups throughout the experiment, although it is not clear whether this increment would persist indefinitely. In addition, although the spectrum of tumor types observed ranged from highly differentiated to poorly differentiated in all treatment groups, DDT and phenobarbital selectively increased the incidence of highly differentiated tumors throughout most of the experiment.

2-Acetylaminofluorene↗

PubMed2001

[Sports, use of performance enhancing drugs and addiction. A conceptual and epidemiological review].

BACKGROUND: Both the general public and non-sports medicine health professionals have recently been made aware of a large use of performance enhancing drugs among sports practicing subjects. It has been suggested that this behavior is similar to that of substance dependence. Also some have reported that practice of a sport could be in itself an addictive behavior. OBJECTIVE: The main objective was to address the following question: is performance enhancing drug use in sports an addictive behavior? Methodology. We first reviewed the definition of performance enhancing drug use in sports and the diagnostic criteria of substance dependence as they are currently accepted and attempted to determine a possible common factor. Secondly we reviewed epidemiological data from the literature according to three approaches: RESULTS: Use of performance enhancing drugs is an important and increasing phenomenon among adolescents. It is sometimes associated to risk taking behaviors for health (syringe use and sharing). Competition participants are at increased risk (up to 20% according to some authors) and some substances (anabolic steroids) are also used by non-sports practicing individuals. It has not been shown that sports practicing subjects were more at risk of using addictive substances compared to non-sports practicing subjects. It is not established that practice of a sport is by itself a risk factor for substance use. However, it could be that a sub-group of individuals that practice certain types of sports in an intensive way, that use both performance enhancing drugs and addictive substances and that engage in health risk taking behaviors have an increased risk for developing a dependence syndrome to both addictive and performance enhancing drugs. This sub-group is even more at risk because some performance enhancing drugs (anabolic steroids) could increase the risk for occurrence of a substance dependence syndrome through neurobiological actions. Yet, the few available clinical studies show that at most only half of regular users actually meet criteria for dependence. Also, one study has reported an overrepresentation of sports professionals among patients seeking treatment for heroin addiction. CONCLUSION: The large majority of sports practicing subjects have no dependence to either performance enhancing or addictive drugs. However, a subgroup of individuals that practice sports intensely and makes use of both addictive and performance enhancing drugs appear to be at increased risk for developing a substance dependence syndrome.

Adolescent↗

PubMed2003

[Diagnosis of periventricular ependymal enhancement in MRI in adults].

Periventricular enhancement in adults at MRI is a significant finding since it often indicates the presence of an underlying disease requiring prompt medical attention. From a review of patients with periventricular enhancement, the main imaging features based on the underlying infectious or tumoral etiology will be described. The presented differential diagnosis is based on the immune status of the patient, type of enhancement, and response to a trial therapy. In immunocompromised patients, the main considerations are lymphoma and viral ependymitis. The pattern of enhancement is important. The presence of thin linear enhancement suggests a viral etiology (cytomegalovirus or varicella-zoster virus) that can be confirmed at CSF evaluation whereas the presence of nodular enhancement suggests a diagnosis of primary CNS lymphoma that can be confirmed by the presence of lymphomatous cells in the CSF or, more frequently, at stereotactic surgical biopsy performed after failure of response to anti-toxoplasmosis treatment. The presence of band enhancement is less specific and can be seen with viral, lymphomatous and even tuberculous involvement. In immunocompetent patients, a clinical context of infection will suggest bacterial or tuberculous ventriculitis and the presence of cystic lesions will suggest cysticercosis; in the absence of constitutional symptoms, the presence of nodular enhancement will suggest a tumoral process (lymphoma, ependymoma, germ cell tumor, or metastases). Rarely, linear enhancement will be due to sarcoidosis or Whipple's disease.

Adult↗

PubMed2003

Contrast-enhanced transabdominal ultrasonography in the diagnosis of pancreatic mass lesions.

PURPOSE: In this study, we evaluated the diagnostic usefulness of contrast-enhanced transabdominal ultrasonography (CE-US) in pancreatic mass lesions that could be detected by US. MATERIAL AND METHODS: CE-US was performed in 37 patients with various pancreatic mass lesions to evaluate the characteristic vascular findings. RESULTS: Pancreatic tubular adenocarcinoma showed negative enhancement pattern in 16 cases and a slight spotty enhancement pattern in 5 cases. Poorly differentiated adenocarcinoma showed slight homogeneous enhancement pattern in 1 case and acinar cell carcinoma was expressed as a heterogeneous enhancement pattern in 3 cases on CE-US. Endocrine cell tumor had a strong homogeneous enhancement pattern in 3 cases, a strong central enhancement in 1 case and a strong peripheral enhancement in 2 cases. Pseudotumorous pancreatitis showed an iso-enhancement pattern in 6 cases. CONCLUSION: CE-US is useful in evaluating the vascularity of the lesions in various pancreatic mass lesions in real-time images, and may be useful for the differential diagnosis of pancreatic mass lesions.

Abdomen↗

PubMed2003

[The characteristics of enhanced gadolinium DTPA brain magnetic resonance images in 298 multiple sclerosis patients].

OBJECTIVE: To investigate the characteristics of enhanced brain magnetic resonance imaging (MRI) with gadolinium-DTPA (GD) in patients with multiple sclerosis (MS). METHODS: Brain enhanced MRI were studied in 186 patients with clinically definite multiple sclerosis. 298 MRI enhanced lesions were followed every 4 weeks and the study lasted 3 months to 2 years. RESULTS: Of the 298 enhanced MRI lesions 207 (69.5%) lasted less than 4 weeks, 251 (84.2%) 8 weeks, and 272 (91.3%) 12 weeks. There were 3 lesions lasting more than 2 years. Round, oval, ring form, arcuate, spotty, or irregular MRI GD enhanced lesions were found in our MS data. CONCLUSIONS: Most of the MRI GD enhanced lesions disappear in 4 weeks. Very few can last more than 2 years. So it is necessary to perform the GD enhanced MRI in 4 weeks for studying MS intracranial GD enhanced lesions. The DA enhanced MRI lesions in MS may be round, oval, ring form, arcuate, spotty or irregular.

Adolescent↗

PubMed2003

Effect of some penetration enhancers on the permeation of glibenclamide and glipizide through mouse skin.

The purpose of this investigation was to study the effect of some penetration enhancers on in vitro permeation of glibenclamide and glipizide through mouse skin. Ethanol in various concentrations, N-methyl-2-pyrrolidinone, transcutol, propylene glycol and terpenes like citral, geraniol and eugenol were used as penetration enhancers. The in vitro skin permeation experiments were conducted by both simultaneous application of drug and enhancer solution and by pretreatment of the skin with neat enhancer. At the end of the experiment drug retained in the skin was estimated. The flux values (microg/cm2/h) of both drugs significantly (p < 0.05) increased in the presence of penetration enhancers, except transcutol and propylene glycol. The glibenclamide flux values ranged from 1.42 +/- 0.09 without enhancer, to 18.25 +/- 1.21 in a combination of 50% ethanol and 5% eugenol. Glipizide flux values ranged from 3.21 +/- 0.51 without enhancer, to 57.21 +/- 5.25 in a combination of 50% ethanol and 5% eugenol. Skin retention and solubility of both drugs increased with all penetration enhancers compared to control (except propylene glycol). As the target permeation rates for glibenclamide and glipizide were calculated to be 193.8 and 184.8 microg/h respectively, the present study showed that the required permeation rates for both drugs could be achieved with the aid of enhancers by increasing the area of application in an appreciable range.

Animals↗

PubMed2004

[Differential patterns of contrast enhancement in different focal liver lesions after injection of the microbubble US contrast agent SonoVue].

PURPOSE: To identify differential contrast enhancement patterns in different focal hepatic lesions after injection of the microbubble contrast agent SonoVue using high or low acoustic power imaging. MATERIAL AND METHODS: Forty-seven focal hepatic lesions (1-8 cm) were detected in 45 patients at unenhanced gray-scale ultrasound (US) and evaluated by color Doppler (CD) US with spectral analysis of tumoral vessels. Lesions were subsequently evaluated by US contrast specific modes after IV bolus administration of 2,4-4,8 ml of SonoVue, by intermittent high acoustic power (18 patients) or by continous low acoustic power imaging (27 patients), during arterial, portal and late phase. Subjective evaluation of lesions appearance before and after SonoVue injection was performed. For final diagnosis multiphasic helical CT (21 patients) and/or fine needle US guided biopsy (24 patients) were considered as the reference procedures. RESULTS: Final diagnoses comprised 22 hepatocellular carcinomas (HCCs; 1,5-6 cm), 2 macroregenerative nodules (RNNs; 1-2 cm), 10 metastasis (2-3,5 cm), 10 hemangiomas (2-6 cm) and 3 focal nodular hyperplasias (FNHs; 1-3 cm). On CD evaluation HCCs revealed peripheral basket shaped (12/22) or intranodular (10/22) arterial pattern while, after SonoVue injection HCCs revealed diffuse contrast enhancement during arterial phase with contrast washout during portal and late phase. Metastases did not reveal flow signals on CD or contrast enhancement after SonoVue injection, except for 2 metastases which revealed peripheral and central vessels on CD and a diffuse contrast enhancement during arterial phase, appearing hypoechoic to the adjacent liver during portal and late phase. RNNs revealed dotted contrast-enhancement during portal and late phase with isoechoic appearance to the adjacent liver. Hemangiomas revealed some peripheral venous flows on CD and a peripheral nodular contrast enhancement during arterial phase with a centripetal fill-in during portal and late phase. FNHs revealed low resistance peripheral or central arterial vessels and a diffuse contrast enhancement during arterial phase, preceded or not by central spoke wheel shaped contrast enhancement, and a persistent iso-hyperechogenicity during portal and late phase. CONCLUSIONS: SonoVue injection has showed to identify differential contrast enhancement patterns in different focal hepatic lesions.

Adult↗

PubMed2005

Characterization of focal liver lesions with a new ultrasound contrast agent using continuous low acoustic power imaging: comparison with contrast enhanced spiral CT.

PURPOSE: To evaluate the concordance of the enhancement patterns of a new ultrasound contrast agent (SonoVue) with those obtained with dual-phase contrast-enhanced spiral CT (CE-CT) in the characterization of focal liver lesions (FLLs). MATERIALS AND METHODS: Sixty-two patients with focal liver lesions discovered at ultrasound and also studied with CECT underwent contrast-enhanced ultrasound using continuous low acoustic power imaging after receiving a 2.4 ml bolus of the new US contrast agent SonoVue, consisting of a dispersion of sulphur hexafluoride microbubbles. The examinations were made using ATL HDI-5000, Acuson SEQUOIA and Aloka 5500 Prosound ultrasound systems with 5.2 MHz curved-array probes. The concordance between US and CE-CT images was evaluated on site by two radiologists blinded to CT RESULTS: The FLLs were assessed in the arterial (20 s after CM injection), portal (after 45-60 s) and late (after 120 s) phases for: 1) presence/absence of enhancement 2) distribution of enhancement (homogenous or target distribution, centripetal or centrifugal flow, and other), 3) qualitative enhancement pattern (hyperechoic, hypoechoic, or isoechoic) versus normal liver parenchyma. RESULTS: The concordance between SonoVue-enhanced US and CE-CT was 85%. Moreover during portal venous phase with CEUS it was possible to differentiate between malignancy or benignity of 91% of lesions. CONCLUSIONS: The preliminary data obtained in this study suggest that continuous low acoustic power imaging and contrast-enhanced US show similar results to CT in contrast distribution and contrast enhancement patterns.

Adult↗

PubMed2004

Evaluation of contrast-enhanced FLAIR sequence in MR assessment of intracranial tumours.

BACKGROUND: Magnetic resonance (MR) has become the most important imaging method in the diagnosis of intracranial tumours. However, conventional MR protocol often fails to obtain all morphological details which are necessary for precise planning of the treatment. Therefore, there are attempts of introducing other MR techniques, to gain new information concerning tumour morphology. One such technique is FLAIR sequence. In previous papers we presented the value of plain FLAIR in patients with intracranial tumours. The aim of the present study was evaluation of contrast enhanced FLAIR (CE FLAIR) in assessment of intracranial tumours. MATERIAL/METHODS: MR examinations, including conventional T1 (pre-and postcontrast) and T2 images, as well as plain and contrast-enhanced FLAIR sequences were performed in 27 patients with intracranial tumours. In all patients the degree and localization of contrast enhancement in post-contrast T1-weighted sequence (CE T1w) and CE FLAIR images have been compared. RESULTS: Contrast enhancement of the tumour in both CE T1-w and CE FLAIR sequences was found in 18 patients. In 5 patients the enhancement was visible only on T1-weighted images, while in 2 cases only on FLAIR images. Among 18 patients, who demonstrated enhancement both in T1-weighted and FLAIR sequences, in 9 cases the effect of enhancement was better on T1-weighted images, in 7-CE FLAIR gave superior results, and in 2 patients - both methods were equivalent. In the whole material in 9 cases CE-FLAIR was superior in 14-inferior and in 4-equal to CE-T1-w. Among 9 cases in which CE- FLAIR was superior, in 7 patients the enhancement concerned the border of the tumour or postoperative cave. CONCLUSIONS: Contrast-enhanced FLAIR has limited value in assessment of intracranial tumours and should be used as a supplementary technique if there are difficulties in evaluation of tumour morphology in other sequences.

Adolescent↗

PubMed1992

Endotoxin enhances the expression of monocyte prothrombinase activity.

Thrombin is generated on the surface of mononuclear cells (MNCs) through the assembly and function of the prothrombinase complex consisting of the enzyme factor Xa, the cofactor/factor Va, calcium ions, and an appropriate membrane surface for proper assembly of the protein constituents. Assays performed in the presence of factors Va and Xa indicated that endotoxin significantly enhanced the prothrombinase activity (1.5- to 2.5-fold; P less than .001) expressed by MNCs in a dose- and time-dependent manner. Monocytes present in the MNC suspensions were responsible for this increased activity through processes resulting in both enhanced cellular activity and the enhanced release of membranous vesicles. Endotoxin was without effect on the expression of lymphocyte prothrombinase activity. Scanning electron microscopy techniques indicated that endotoxin resulted in extensive membrane blebbing of the monocytes present in the MNC suspensions with no effect on the morphology of the lymphocytes. Within 5 hours, endotoxin maximally enhanced the prothrombinase activity expressed by the monocyte membrane surface 2.8-fold, whereas 8 hours was required to maximally enhance the activity associated with the released vesicles by twofold. The observed increase in activity expressed by the monocyte membrane surface was due solely to endotoxin, since the activity expressed by the unstimulated monocyte membrane surface remained unaltered over time. In contrast, cell vesiculation, which occurred in the absence of any stimulus, was further enhanced by endotoxin. The increase in activity associated with the released vesicles from both stimulated and unstimulated cells paralleled an increase in the vesicle number as determined by flow cytometric analyses. The vesicle released from both unstimulated and stimulated monocytes were indistinguishable in size as determined by image analysis and ranged between 0.05 and 0.3 microns in diameter. 2-Deoxy-D-glucose (2DG) significantly enhanced the prothrombinase activity expressed by the monocyte membrane surface, as well as the released vesicle fraction, when used alone or in addition to endotoxin. The enhanced activity associated with the vesicle fraction again was attributed to the release of more vesicles. In contrast, cycloheximide decreased the prothrombinase activity expressed by the monocyte membrane surface, as well as the activity associated with vesicles released from both stimulated and unstimulated cells. These data suggest that the expression of monocyte prothrombinase activity can be significantly enhanced by endotoxin through processes that alter the monocyte membrane surface and augment the vesiculation process. Both processes appear to be regulated by protein synthesis and adenosine triphosphate (ATP)-dependent mechanisms.

Blood Proteins↗

PubMedDate not supplied

Spinal epidural abscess: evaluation with contrast-enhanced MR imaging.

Seven patients with spinal epidural abscess were evaluated with MR imaging. T1-weighted images were obtained before and after administration of gadopentetate dimeglumine, and contrast-enhanced images were compared with available T2-weighted images and unenhanced T1-weighted images. In all seven cases, the epidural infection was iso- to hypointense compared with the spinal cord on unenhanced T1-weighted images, and increased in intensity on proton-density- and T2-weighted images. Three patterns of enhancement were observed after contrast administration. In three patients the infection enhanced homogeneously, likely representing thickened, inflammed tissue with microabscesses and granulomatous material. In one patient, peripheral enhancement surrounded a central focus of low signal intensity, representing necrotic abscess. In two patients, a combination of both patterns was observed. One abscess infiltrated the posterior thoracic epidural fat, producing decreased signal within the high-signal fat on T1-weighted images. Enhanced T1-weighted images were equivalent to unenhanced T2-weighted images in detecting the extent of epidural involvement in three cases. In two cases, enhanced T1-weighted images were superior to T2-weighted images in differentiating the infectious component from surrounding CSF. In one case, contrast administration produced no discernible enhancement. Enhanced images also provided important information regarding the composition of the abscess (liquid versus solid). Contrast-enhanced MR images are valuable in the characterization of spinal epidural abscesses.

Abscess↗