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PubMed1991

1,25-Dihydroxycholecalciferol enhances both the bombesin-induced transient in intracellular free Ca2+ and the bombesin-induced secretion of prolactin in GH4C1 pituitary cells.

In GH4C1 rat pituitary cells, 1,25-dihydroxycholecalciferol [1,25-(OH)2D3] enhances both the synthesis of PRL and the TRH-induced transient increase in cytosolic free calcium ( [Ca2+]i). In the present report we investigated whether 1,25-(OH)2D3 could enhance the effect of the tetradecapeptide bombesin (BBS) in GH4C1 cells. Pretreatment of the cells with 1 nM 1,25-(OH)2D3 for 24 h enhanced the BBS-induced transient increase in [Ca2+]i compared to that in control cells, while having no significant effect on the plateau phase of [Ca2+]i. Addition of the Ca2+ channel blocker nimodipine or chelating extracellular Ca2+ with EGTA did not abolish the enhancement of the BBS response in 1,25-(OH)2D3-pretreated cells. Furthermore, the BBS-induced efflux of 45Ca2+ from cells preequilibrated with 45Ca2+ was larger in cells treated with 1,25-(OH)2D3. Incubating GH4C1 cells with 1,25-(OH)2D3 alone or in combination with BBS for up to 72 h did not stimulate synthesis of PRL. However, the BBS-induced secretion of PRL was enhanced in cells pretreated with 1,25-(OH)2D3 for 24 h compared with that in vehicle-treated control cells. The effect of 1,25-(OH)2D3 on BBS-induced secretion was dose dependent, with 10(-11) M 1,25-(OH)2D3 enhancing the stimulated secretion of PRL. We conclude that in GH4C1 cells, pretreatment with 1,25-(OH)2D3 enhances the BBS-induced transient increase in [Ca2+]i. This effect may be due to a modulation of the availability of sequestered intracellular Ca2+ and/or membrane Ca2+ conductance. Furthermore, pretreatment with 1,25-(OH)2D3 enhanced secretion of PRL stimulated by BBS. The enhanced transient increase in [Ca2+]i may be the factor inducing the enhanced BBS-induced secretion of PRL.

Animals↗

PubMed2001

The effect of IFNbeta-1b on the evolution of enhancing lesions in secondary progressive MS.

BACKGROUND: After the resolution of contrast enhancement, the majority of new MS lesions become isointense with surrounding white matter on T1-weighted MRI. Less commonly, a hypointense T1 lesion develops, representing the development of more severe focal tissue damage. Interferon beta (IFNbeta) reduces both the number of new enhancing lesions and the duration of contrast enhancement. OBJECTIVE: To determine if IFNbeta affects the degree of tissue damage within new lesions and if its effects are related to lesion size. METHODS: One hundred twenty-five patients with secondary progressive MS from seven European sites were randomized to receive either IFNbeta-1b or placebo. Monthly, contrast-enhanced T1-weighted MR images were acquired at baseline, at months 1 to 6, and at months 19 to 24. The size of all new enhancing lesions developing between months 1 and 6 was recorded and their appearance at follow-up documented. RESULTS: In the first 6 months, fewer new enhancing lesions occurred in the IFNbeta-1b arm. This difference was greater for small (70% decrease) than for large (46% decrease) lesions. Hypointense T1 lesions were more likely to form from large (25%) than from small (9%) enhancing lesions in both treatment arms. Patients taking IFNbeta-1b developed fewer hypointense T1 lesions; however, the proportion of enhancing lesions developing into hypointense T1 lesions was similar in both arms. CONCLUSION: IFNbeta-1b reduced the number of new enhancing lesions, with a greater effect on small lesions. However, when a new enhancing lesion did become established, treatment with IFNbeta-1b did not alter its subsequent course.

Adult↗

PubMed2000

Electrophysiological studies on the evaluation of absorption enhancers in Caco-2 cells using a microelectrode technique.

We developed a microelectrode technique to characterize the electrophysiological properties in Caco-2 cells, and used it to determine the mechanisms of absorption enhancers. The action of absorption enhancers on the apical membrane of Caco-2 cells was estimated by measuring the apical membrane potential (Vm) with the microelectrode. The Vm value of Caco-2 cells in Hanks' balanced salt solution containing 0.5 mM K+ was 18.9+/-0.8 mV (n=217), and the apical membrane resistance was 49.4+/-1.1 MOhms (n=160). In the electrophysiological study with absorption enhancers, laurylmaltoside (LM) markedly decreased the Vm value, while sodium glycocholate (NaGC) moderately reduced this value, and EDTA did not affect the value. These findings might be associated with their action sites, plasma membrane or tight junction in Caco-2 cell monolayers. In influx and transport studies with these absorption enhancers, LM enhanced the influx of furosemide, which is transported via both the transcellular and paracellular routes into Caco-2 cells, and enhanced its transport to the basolateral side of Caco-2 monolayers more than that of 5(6)-carboxyfluorescein (CF), a paracellular marker. EDTA did not increase the influx of furosemide, and enhanced the transport of furosemide and CF across Caco-2 cell monolayers to the same extent. In contrast, NaGC only slightly increased the influx of furosemide and did not enhance the transport of either furosemide or CF across the Caco-2 monolayers in this study. These findings were well correlated with the effects of these absorption enhancers on the electrophysiological parameters. Therefore, the microelectrode technique might be useful for evaluating the action of absorption enhancers in the plasma membrane at an intact cell level.

Caco-2 Cells↗

PubMed1990

Duration of absorption-enhancing effect of sodium octanoate, sodium hexanoate or glyceryl-1-monooctanoate on rectal absorption of gentamicin in rabbits.

The duration of the absorption-enhancing effect of sodium octanoate (C8), sodium hexanoate (C6) and glyceryl-l-monooctanoate (MO) on the rectal absorption of gentamicin (GM) using the hollow-type suppository was investigated in rabbits. To evaluate the duration of the absorption-enhancing effect by pretreatment (treatment of absorption enhancer before GM administration), suppository I containing each absorption enhancer in the cavity was administered into the rectum. Then suppository II containing GM in the cavity was administered at predetermined times (0.33, 2, 6 and 24 h) after the administration of suppository I. Plasma GM levels obtained by the pretreatment with absorption enhancer were compared with those obtained by the simultaneous administration of GM with absorption enhancer. The AUC and Cmax of GM significantly decreased with the pretreatment of C8 (6 and 24 h), C6 (2 and 6 h) or MO (6 and 24 h) before rectal GM administration, as compared with the simultaneous administration of GM with C8, C6 or MO. A marked decrease in the absorption-enhancing effect of C8, C6 and MO on rectal GM absorption was observed by the prolongation of the period between the pretreatment of each absorption enhancer and GM administration. The duration of the absorption-enhancing effect of C6 was shorter than that of C8, whereas this duration of MO was similar to that of C8. The effect of these absorption enhancers disappeared 24 h after the pretreatment. These results suggested that the lowering of the membrane transport barrier function recovered about one day after the administration of C8 or MO.

Administration, Rectal↗

PubMed2000

[Transdermal delivery of drugs and enhancement of percutaneous absorption].

This paper describes 1) the drug delivery through the skin to produce systemic effects, 2) the enhancement of percutaneous absorption by absorption enhancers, heating and complex formation, 3) the mechanism for the enhancement effect by enhancers, 4) the percutaneous absorption of peptides, and 5) the pharmacokinetic analysis for percutaneous absorption. 1,3-Dinitroglycerin, indomethacin (IND) and many drugs were efficiently absorbed via rat and rabbit skins in the presence of some enhancers, and using a microporous membrane therapeutic plasma concentrations were maintained for a long time. Enhancement of percutaneous absorption by the complex formation with fatty acid was observed for propranolol (PL) in vitro and in vivo. Heating at 42-45 degrees C also enhanced the percutaneous absorption dramatically, with decreased activation energies. The following mechanisms for the enhancement effect by enhancers were found: a) an increase in the fluidity of the stratum corneum lipids and reduction in the diffusional resistance to permeants, b) the removal of intercellular lipids and dilation between adherent cornified cells, c) an increase in the thermodynamic activity of drugs in vehicles, d) the exfoliation of stratum corneum cell membranes, the dissociation of adherent cornified cells and elimination of the barrier function. Peptides such as enkephalin, elcatonin and insulin were effectively absorbed through the skin in the presence of some enhancers and specific inhibitors, with no proteolytic degradation. The pharmacokinetic model with two parallel absorption processes, lipidic and aqueous pore transport pathways, in skin could adequately describe the percutaneous absorption of IND, PL and valproic acid. With peptides, a kinetic model including zero-order input rate, first-order permeation rate and first-order degradation rate was able to describe well the steady-state flux of peptides.

Animals↗

PubMed2004

Castleman's disease of the neck: a description of four cases on contrast-enhanced CT.

Castleman's disease of the neck is an uncommon benign lymphoproliferative disease that usually presents as homogeneously enhancing enlarged lymph nodes on contrast-enhanced CT scan. We described the appearance of four confirmed cases of Castleman's disease of the neck on contrast-enhanced CT scan. Three of these presented as a solitary enhancing lymph node and the fourth case presented with multiple bilateral enhancing lymph nodes. A central non-enhancing area was present in two of the three cases that presented as a solitary node. Pathological correlation of one of these cases showed that this was due to a central fibrotic scar. One of the enhancing nodes in the fourth case with multiple and bilateral lymphadenopathy also contained a central non-enhancing area. We would like to propose that if a central non-enhancing scar is observed in an enhancing lymph node in the neck on CT scan, Castleman's disease should be considered as a possible diagnosis.

Adolescent↗

PubMedDate not supplied

Effects of enhanced UV-B on pigment-based phytoplankton biomass and composition of mesocosm-enclosed natural marine communities from three latitudes.

A series of three outdoor mesocosm experiments was undertaken in Rimouski (Canada), Ubatuba (Brazil) and Ushuaia (southern Argentina) to examine the effects of lamp-enhanced UV-B (280-320 nm) on phytoplankton communities isolated from seawater at each site. Detailed pigment composition was used to identify these communities. Each experiment compared three replicated UV-B treatments, consisting of natural sunlight conditions (NUVB), low-level UV-B enhancement corresponding to local 30% ozone depletion (LUVB) and high-level enhancement corresponding to 60% ozone depletion (HUVB). Each mesocosm (ca 2 m deep) was mixed continuously (turnover time, ca 1.3 h) and samples were obtained daily over 7-10 days. In Rimouski a large diatom bloom occurred during the first week. Repeated-measures analysis of variance (RM-ANOVA), with time as the repeated factor, showed slight but statistically significant increases in the chlorophyll (Chl) a level with the HUVB treatment, which were especially obvious over the last 3 days of the experiment. A large decrease in grazers (ciliates) that was observed concurrently with this treatment is the most likely explanation for the increase in Chl a level. The lack of negative effect on algal biomass by enhanced UV-B is attributed to the mixing inside the mesocosms and to the relatively low UV-B penetration. In Ubatuba levels of most pigments decreased over time, particularly fucoxanthin, Chl c3 and alloxanthin. The RM-ANOVA showed no effect of the UV-B treatments, except for Chl c3, which had significantly lower concentrations under natural UVB conditions, indicating that enhanced UV-B directly or indirectly favored Chl c3 algae (likely prymnesiophytes). Although particulate organic carbon concentration was significantly larger during HUVB treatment than during the other treatments, Chl a was unaffected, suggesting that enhanced UV-B favored heterotrophs. Lack of algal growth during this experiment was attributed to low nutrient concentrations (which were the lowest of the three sites), high irradiances (which were the highest noon incident photosynthetically available radiation and UV of the three sites) and UV-B penetration down to the bottom of the mesocosms. In Ushuaia a small bloom took place over the first 5 days. The RM-ANOVA showed no overall effect of the UV-B treatments for any of the pigments examined but on the last 3 days of the experiment several green algae-type pigments, such as Chl b and siphonein, showed increased concentrations under the HUVB treatment. UV-B enhancement hence favored green algae, as seen from the stronger increase over time in the ratio of Chl b to Chl a associated with the HUVB treatment. UV-B enhancement also seemed to cause a slight decrease in physiological condition, because the relative concentration of chlorophyllide a and some pheophorbides that may be the product of dying algae increased during the HUVB treatments in Ubatuba and particularly in Ushuaia (where UV-B also penetrated to the bottom of mesocosms). For all three sites changes in phytoplankton biomass due to the UV-B treatments were minor, even though UV-B enhancement was important. This study indicates that effects of enhanced UV-B on the community structure of both phytoplankton and their grazers are potentially more important than effects on overall algal biomass.

Biomass↗

PubMed2006

Is there an optimal training intensity for enhancing the maximal oxygen uptake of distance runners?: empirical research findings, current opinions, physiological rationale and practical recommendations.

The maximal oxygen uptake (V-dotO(2max)) is considered an important physiological determinant of middle- and long-distance running performance. Little information exists in the scientific literature relating to the most effective training intensity for the enhancement of V-dotO(2max) in well trained distance runners. Training intensities of 40-50% V-dotO(2max) can increase V-dotO(2max) substantially in untrained individuals. The minimum training intensity that elicits the enhancement of V-dotO(2max) is highly dependent on the initial V-dotO(2max), however, and well trained distance runners probably need to train at relative high percentages of V-dotO(2max) to elicit further increments. Some authors have suggested that training at 70-80% V-dotO(2max) is optimal. Many studies have investigated the maximum amount of time runners can maintain 95-100% V-dotO(2max) with the assertion that this intensity is optimal in enhancing V-dotO(2max). Presently, there have been no well controlled training studies to support this premise. Myocardial morphological changes that increase maximal stroke volume, increased capillarisation of skeletal muscle, increased myoglobin concentration, and increased oxidative capacity of type II skeletal muscle fibres are adaptations associated with the enhancement of V-dotO(2max). The strength of stimuli that elicit adaptation is exercise intensity dependent up to V-dotO(2max), indicating that training at or near V-dotO(2max) may be the most effective intensity to enhance V-dotO(2max) in well trained distance runners. Lower training intensities may induce similar adaptation because the physiological stress can be imposed for longer periods. This is probably only true for moderately trained runners, however, because all cardiorespiratory adaptations elicited by submaximal training have probably already been elicited in distance runners competing at a relatively high level.Well trained distance runners have been reported to reach a plateau in V-dotO(2max) enhancement; however, many studies have demonstrated that the V-dotO(2max) of well trained runners can be enhanced when training protocols known to elicit 95-100% V-dotO(2max) are included in their training programmes. This supports the premise that high-intensity training may be effective or even necessary for well trained distance runners to enhance V-dotO(2max). However, the efficacy of optimised protocols for enhancing V-dotO(2max) needs to be established with well controlled studies in which they are compared with protocols involving other training intensities typically used by distance runners to enhance V-dotO(2max).

Adaptation, Physiological↗

PubMed2006

An algorithm for the diagnosis of focal liver masses using microbubble contrast-enhanced pulse-inversion sonography.

OBJECTIVE: The objective of this study was to develop an algorithm for liver mass diagnosis using microbubble contrast-enhanced pulse-inversion sonography. SUBJECTS AND METHODS: Ninety-six lesions in 92 patients were evaluated with DMP 115 (Definity)-enhanced pulse-inversion sonography, comprising 44 malignancies (29 hepatocellular carcinomas, 12 metastases, two peripheral cholangiocarcinomas, and one hepatic lymphoma) and 52 benign lesions (26 hemangiomas, 20 focal nodular hyperplasias, and six others). All had continuous low-mechanical-index imaging through the arterial and portal venous phase. A three-person blind review evaluated single images at baseline, early and peak arterial phases, and through the extended portal phases with a movie showing arterial phase wash-in. Reviewers assessed lesional vascularity and enhancement blindly but did not make a diagnosis. Combinations of answers were compared with independently determined final diagnoses to develop an algorithm for liver mass diagnosis. RESULTS: Portal phase enhancement comprises the first step of the algorithm, with positive or sustained enhancement identifying 48 (92%) of 52 benign lesions and negative enhancement or washout present in 41 (93%) of 44 malignancies. Sustained portal phase enhancement with arterial phase peripheral nodularity and centripetal progression predicted 24 (92%) of 26 of the hemangiomas; diffuse arterial phase enhancement greater than the liver identified 19 (95%) of 20 of the focal nodular hyperplasias. With negative portal phase enhancement, arterial phase information was less effective at differentiating hepatocellular carcinoma (25 [86%] of 29 cases) from another hepatic malignancy (11 [73%] of 15 cases). CONCLUSION: A simple diagnostic algorithm for interpretation of microbubble-enhanced sonography provides sensitive and accurate diagnosis of commonly encountered liver masses.

Adolescent↗

PubMed1989

Dyke award. Gd-DTPA-enhanced MR imaging of experimental bacterial meningitis: evaluation and comparison with CT.

Gd-DTPA-enhanced MR images of experimental bacterial meningitis were obtained after Staphylococcus aureus was inoculated directly into the cisterna magna of four dogs. Each animal was studied with both unenhanced and enhanced MR and CT with Gd-DTPA and meglumine iothalamate, respectively. The enhancement patterns resulting from these techniques were compared and images were correlated with histopathology. All animals demonstrated abnormal leptomeningeal enhancement on MR with Gd-DTPA, but only one of four dogs exhibited abnormal contrast enhancement on CT. In these animals Gd-DTPA-enhanced MR also identified complications of meningitis, such as ventriculitis and cerebritis, more effectively than CT did. Unenhanced MR was not helpful in identifying meningitis. Histologic evaluation demonstrated that the abnormal areas of contrast enhancement on MR and CT correlated with inflammatory cell infiltration. However, some regions of mild leptomeningitis, ependymitis, and cerebritis identified histologically did not demonstrate abnormal enhancement. Since the animal model used was clinically and pathologically similar to human meningitis, we propose that Gd-DTPA-enhanced MR will subsequently be found more effective than unenhanced MR and IV contrast-enhanced CT for demonstrating meningitis and its complications in humans.

Animals↗

PubMed1994

Cost-effective use of low-osmolality contrast media for CT of the liver: evaluation of liver enhancement provided by various doses of iohexol.

OBJECTIVE: Because of pending efforts to reform health care in the United States, judicious use of low-osmolality contrast media is important. We studied the effects of using various concentrations and volumes of iohexol, compared with the conventional dose and concentration of diatrizoate meglumine used for CT, to determine if a more cost-effective dose results in diagnostically efficacious liver enhancement. SUBJECTS AND METHODS: A total of 902 patients received one of nine different doses of IV contrast media. Eight doses of iohexol were used: 125 ml of iohexol 350 (350 mg l/ml, 44 g l/dose), 100 ml of iohexol 350 (35 g l/dose), 150 ml of iohexol 300 (300 mg l/ml, 45 g l/dose), 120 ml of iohexol 300 (36 g l/dose), 100 ml of iohexol 300 (30 g l/dose), 175 ml of iohexol 240 (240 mg l/ml, 42 g l/dose), 150 ml of iohexol 240 (36 g l/dose), and 125 ml of iohexol 240 (30 g l/dose). A single dose (150 ml) of diatrizoate meglumine 60% (w/v) was used (42 g l/dose). Contrast material was injected at a rate of 2 ml/sec. Scanning began 35-45 sec after injection. Quantitative analysis of enhancement was performed by obtaining region-of-interest measurements through the liver on scans obtained before and after injection of contrast material. Mean and maximum changes in hepatic density and mean time to maximum enhancement were measured. Mean time-density curves were subsequently derived for each dose of contrast material. Qualitative analysis of enhancement was performed by using subjective, previously defined criteria. All studies were interpreted in a double-blind fashion. RESULTS: Mean hepatic enhancement was greater with 125 ml of iohexol 350 and 150 ml of iohexol 300 than with other doses of contrast material (p < .05). Both 125 ml of iohexol 350 and 150 ml of iohexol 300 produced actual hepatic enhancement of more than 50 H for over 60 sec. The greatest maximum increase in hepatic density occurred with 125 ml of iohexol 350. When analyzed qualitatively, 150 ml of iohexol 300 resulted in the highest percentage of optimum enhancement. CONCLUSION: According to quantitative analysis, 125 ml of iohexol 350 administered at a rate of 2 ml/sec produces the best enhancement, whereas according to qualitative analysis, 150 ml of iohexol 300 produces the best enhancement. All doses of iohexol 240 provide poor enhancement compared with a conventional dose of contrast material of 150 ml of diatrizoate meglumine 60% or 150 ml of iohexol 300. A moderate cost savings can be achieved by using 125 ml of iohexol 350 for dynamic sequential CT.

Cost-Benefit Analysis↗

PubMed1998

Variability in the detection of enlarged mediastinal lymph nodes in staging lung cancer: a comparison of contrast-enhanced and unenhanced CT.

OBJECTIVE: Because CT protocols for staging lung cancer vary and little information exists regarding the diagnostic importance of using i.v. contrast material, our intent was to evaluate intra- and interobserver agreement in the detection of enlarged mediastinal lymph nodes, comparing i.v. contrast-enhanced and unenhanced CT. SUBJECTS AND METHODS: Fifty patients with known or suspected bronchogenic carcinoma underwent unenhanced thoracic CT followed by contrast-enhanced CT. Three observers noted enlarged lymph nodes (> 10 mm in the short axis) and assigned the enlarged nodes to American Thoracic Society nodal station designations. Enlarged lymph nodes were grouped two ways: by assigning the exact number of enlarged lymph nodes found (zero, one, two, three, four or more), and by assigning whether at least one, or no, enlarged mediastinal lymph nodes were found at a station ("one or none"). Agreement levels were determined for inter- and intraobserver interpretations using weighted kappa statistics and the McNemar test. RESULTS: The number of enlarged lymph nodes with enhanced CT was 11% higher than on unenhanced studies (418 versus 377; p = .044). Numbers of enlarged lymph nodes were different for five stations; however, the numbers were small except for the right upper paratracheal station (2R) (contrast-enhanced, 68 enlarged lymph nodes; unenhanced, 44 enlarged lymph nodes; p = .014). With regard to all stations together, intraobserver agreement between contrast-enhanced and unenhanced studies was almost perfect (kappa range, .85-.94), and no difference was found for any observer in the proportion of patients with at least one enlarged lymph node. Interobserver agreement was substantial or almost perfect for the total number of enlarged lymph nodes. For specific stations, the lowest kappa value was .48 at 2R. One observer reported more patients with at least one enlarged lymph node with contrast enhancement at station 2R (p = .031). Greater agreement existed between two observers at station 2R with contrast enhancement versus no enhancement (kappa = .85 versus .48; p = .02). Conclusions matched, and calculations of estimated kappa values gave similar results for determination of the specific number of enlarged lymph nodes at a station and the "one or none" category. CONCLUSION: We found high agreement for intra- and interobserver interpretations for contrast-enhanced and unenhanced CT, although contrast-enhanced CT revealed more enlarged lymph nodes, especially at station 2R.

Adult↗

PubMed1999

Using helical CT to evaluate renal cell carcinoma in patients undergoing hemodialysis: value of early enhanced images.

OBJECTIVE: The purpose of this study was to evaluate early and delayed enhanced helical CT for revealing renal cell carcinoma in patients undergoing hemodialysis. MATERIALS AND METHODS: Over the course of 3 years, 630 chronic hemodialysis patients underwent early and delayed contrast-enhanced and unenhanced helical CT to detect renal cell carcinoma. Retrospective review showed that 23 of these patients later underwent either unilateral or bilateral nephrectomy. Two radiologists, unaware of the pathology results, independently reviewed these 23 examinations. The sensitivity and specificity of each early and delayed scan for revealing neoplasms were determined using pathology as the gold standard. The mean attenuation values of the neoplasms and parenchymas of end-stage kidneys on both early and delayed enhanced images were also compared. RESULTS: Helical CT revealed 225 lesions, 24 of which were found to be renal cell carcinomas at pathology. Delayed enhanced helical CT failed to detect one papillary carcinoma in an end-stage kidney with acquired cysts. Three nonpapillary carcinomas were not detected on delayed scans, and one was missed on an early scan of a patient without acquired cysts. The sensitivity and specificity of early enhanced CT for revealing renal cell carcinoma were 96% and 95%, respectively. In contrast, delayed enhanced CT achieved a sensitivity of 83% and a specificity of 94%. A significant difference in mean attenuation values between carcinomas and renal parenchymas was observed on the images with early enhancement but not on those with delayed enhancement (p < .0001). CONCLUSION: Early enhanced helical CT is superior to delayed enhanced helical CT for revealing renal cell carcinoma in end-stage kidneys.

Carcinoma, Renal Cell↗

PubMed2003

Dynamic CT of acute cholangitis: early inhomogeneous enhancement of the liver.

OBJECTIVE: Our objective was to describe the dynamic CT findings of acute cholangitis, especially early inhomogeneous enhancement of hepatic parenchyma. MATERIALS AND METHODS: Inhomogeneous enhancement of hepatic parenchyma was retrospectively evaluated on dynamic CT in 406 consecutive patients without irregular fatty liver or multiple hepatic tumors. Dynamic CT scans were obtained 30 sec (early phase) and 90 sec (late phase) after starting the contrast material injection. Thirteen patients were diagnosed as having acute cholangitis (cholangitis group), and the remaining 393 patients were classified as the control group. The frequency of inhomogeneous enhancement was compared between these two groups. In nine of the 13 patients in the cholangitis group, we also evaluated changes in inhomogeneous enhancement on follow-up dynamic CT scans obtained after the patients had undergone treatment for acute cholangitis. RESULTS: In the cholangitis group, 11 (85%) of 13 patients showed nodular, patchy, wedge-shaped, or geographic inhomogeneous enhancement throughout the liver in the early phase on dynamic CT. In the control group, 19 (5%) of 393 patients also showed inhomogeneous enhancement in the early phase on dynamic CT. The frequency of inhomogeneous enhancement was significantly higher in the cholangitis group than in the control group (p < 0.001). Follow-up dynamic CT performed after treatment for acute cholangitis showed decreased inhomogeneous enhancement or no inhomogeneous enhancement in seven (78%) of nine patients in the cholangitis group. CONCLUSION: Inhomogeneous enhancement in the early phase on dynamic CT is frequently seen in patients with acute cholangitis; this finding usually disappears after treatment.

Acute Disease↗

PubMed2004

Small (<or= 2 cm) hepatic lesions in colorectal cancer patients: detection and characterization on mangafodipir trisodium-enhanced MRI.

OBJECTIVE: The purpose of this study was to evaluate whether mangafodipir trisodium (MnDPDP)-enhanced MRI improves the detection and characterization of small ( 2.0 cm). The differences between MnDPDP-enhanced MRI and helical CT with regard to the detection rates for hepatic lesions and metastases and with regard to the false-positive rates for hepatic metastases were analyzed using the McNemar test. The performances of MnDPDP-enhanced MRI and helical CT in indicating metastases of focal liver lesions were analyzed using receiver operating characteristic curves. RESULTS: No statistically significant differences were seen between MnDPDP-enhanced MRI and helical CT in the detection of all hepatic lesions (p = 0.383) and small lesions (p = 0.210). However, concerning the differentiation between benign and metastatic lesions, MnDPDP-enhanced MRI was superior to helical CT both for all hepatic lesions (p = 0.023) and for small lesions (p = 0.015), and remained better when the analyses were restricted to patients with histopathologic confirmation (p = 0.023 for both). MnDPDP-enhanced MRI changed the diagnosis of hepatic metastasis in nine (13.0%) of 69 patients. Of 12 metastases that were found on MnDPDP-enhanced MRI and missed on helical CT, 11 lesions (91.7%) were small. MnDPDP-enhanced MRI showed a significantly greater detection rate than helical CT for small hepatic metastases (p = 0.022). MnDPDP-enhanced MRI was better when the analyses were restricted to patients with histopathologic confirmation (p = 0.043). CONCLUSION: Although MnDPDP-enhanced MRI is equal to helical CT in detection of both all hepatic lesions and small lesions in patients with colorectal carcinoma, it is superior to CT in characterization of the lesions.

Adult↗

PubMed2006

Bryostatin enhancement of memory in Hermissenda.

Bryostatin, a potent agonist of protein kinase C (PKC), when administered to Hermissenda was found to affect acquisition of an associative learning paradigm. Low bryostatin concentrations (0.1 to 0.5 ng/ml) enhanced memory acquisition, while concentrations higher than 1.0 ng/ml down-regulated the pathway and no recall of the associative training was exhibited. The extent of enhancement depended upon the conditioning regime used and the memory stage normally fostered by that regime. The effects of two training events (TEs) with paired conditioned and unconditioned stimuli, which standardly evoked only short-term memory (STM) lasting 7 min, were--when bryostatin was added concurrently--enhanced to a long-term memory (LTM) that lasted about 20 h. The effects of both 4- and 6-paired TEs (which by themselves did not generate LTM), were also enhanced by bryostatin to induce a consolidated memory (CM) that lasted at least 5 days. The standard positive 9-TE regime typically produced a CM lasting at least 6 days. Low concentrations of bryostatin (<0.5 ng/ml) elicited no demonstrable enhancement of CM from 9-TEs. However, animals exposed to bryostatin concentrations higher than 1.0 ng/ml exhibited no behavioral learning. Sharp-electrode intracellular recordings of type-B photoreceptors in the eyes from animals conditioned in vivo with bryostatin revealed changes in input resistance and an enhanced long-lasting depolarization (LLD) in response to light. Likewise, quantitative immunocytochemical measurements using an antibody specific for the PKC-activated Ca2+/GTP-binding protein calexcitin showed enhanced antibody labeling with bryostatin. Animals exposed to the PKC inhibitor bisindolylmaleimide-XI (Ro-32-0432) administered by immersion prior to 9-TE conditioning showed no training-induced changes with or without bryostatin exposure. However, if animals received bryostatin before Ro-32, the enhanced acquisition and demonstrated recall still occurred. Therefore, pathways responsible for the enhancement effects induced by bryostatin were putatively mediated by PKC. Overall, the data indicated that PKC activation occurred and calexcitin levels were raised during the acquisition phases of associative conditioning and memory initiation, and subsequently returned to baseline levels within 24 and 48 h, respectively. Therefore, the protracted recall measured by the testing regime used was probably due to bryostatin-induced changes during the acquisition and facilitated storage of memory, and not necessarily to enhanced recall of the stored memory when tested many days after training.

Animals↗

PubMed2002

Contrast-enhanced two- and three-dimensional sonography for evaluation of intra-abdominal hemorrhage.

OBJECTIVE: To determine whether a contrast agent enhances sonographic detection of bleeding sites in the abdomen and whether contrast-enhanced three-dimensional sonography provides additional information compared with contrast-enhanced two-dimensional sonography. METHODS: Bleeding sites were created within the livers (n = 3), spleens (n = 5), and kidneys (n = 3) of 3 dogs. A sonographic contrast agent with vascular and parenchymal enhancement capabilities was administered intravenously at a dose of 0.02 mL/kg. Before and after each contrast agent injection, the bleeding sites were imaged with two- and three-dimensional sonography in gray scale harmonic imaging and color flow modes. Sonographic findings were compared with gross pathologic findings. RESULTS: Noncontrast-enhanced sonography was not able to show the specific location of the active bleeding in any of the organs evaluated. The contrast agent enhanced the sonographic detection of blood flow in normal vessels and extravasated blood from damaged vessels or organs in all cases. Intrasplenic and intrahepatic hematomas were better identified on delayed imaging sequences because there was marked enhancement of the normal parenchyma, whereas the hematomas remained unenhanced. Reconstructed three-dimensional sonography showed spatial relationships of the bleeding sites and surrounding structures. Gross pathologic findings were consistent with the contrast-enhanced sonographic results. CONCLUSIONS: Contrast-enhanced sonography improves the detection and evaluation of abdominal bleeding sites. Contrast-enhanced three-dimensional sonography appears to provide additional information when compared with two-dimensional sonography.

Animals↗

PubMed1975

Immunologic and physicochemical properties of enhancing soluble factors for IgG and IgE antibody responses.

Rabbits were immunized with dinitrophenyl-coupled Ascaris antigen (DNP-Asc) or ragweed antigen (DNP-Rag) included in aluminum hydroxide gel and their mesenteric lymph node cells were cultured for 24 hr in vitro in the presence of free homologous carrier. The cell-free supernatant thus obtained enhanced both IgG and IgE antihapten antibody responses of DNP-primed cells to DNP-heterologous carrier conjugate (DNP-keyhole limpet hemocyanin). Since the cell-free supernatant obtained from Rag-specific cells enhanced antibody response of hapten-primed cells raised by immunization with DNP-Asc, no carrier specificity was involved in the enhancement. It was found that treatment of primed cells with 10-5 M pactamycin suppressed the formation of the enhancing soluble factor, whereas the factor was readily formed in the presence of 2 mug/mol of cytosine arabinoside in the culture. The results indicated that cell proliferation was not required but de novo synthesis of protein was essential for the formation of soluble factor(s). The enhancing factor was not absorbed by either carrier-coated or anti-carrier antibody-coated immunosorbent. It was also found that the enhancing factor was formed by incubating primed cells with carrier-coated Sepharose. The cell-free supernatant containing no free carrier enhanced both IgG and IgE anti-hapten antibody responses. The activities of the cell-free supernatant to enhance IgG and IgE antibody responses were not absorbed by anti-Fab, anti-gamma-or anti-mu-chain antibody immunosorbent, indicating that the nonspecific enhancing factor did not possess immunoglobulin determinant. The cell-free supernatant was fractionated by sucrose density gradient ultracentrifugation and by gel filtration with three radiolabeled proteins, i.e., IgG, ovalbumin, and cytochrome C as markers. Enhancing activity for IgG antibody response was recovered in a fraction between ovalbumin peak (40,000 m.w.) and cytochrome C peak (20,000 m.w.). The activity for IgE antibody response was recovered in a fraction containing IgG marker (150,000 m.w.). By block electrophoresis, both activities were detected in beta globulin fraction. The results suggested that different T cell factors are involved in the IgG and IgE antibody responses.

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