Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “Barium Compounds”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

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

At least 1,297 records · Page 72Linked to original sources
PubMed2000

Tc-99m-PEG-Liposomes for the evaluation of colitis in Crohn's disease.

In the present study, the potential role of 99mTc-PEG-liposome to determine the extent and severity of active disease of Crohn's colitis was investigated. Patients suspected of having an exacerbation of Crohn's disease underwent a 99mTc-PEG-liposome scan (740 MBq, imaging at 4 and 24 h p.i.). A barium enema or endoscopy was performed as the standard verification procedure. Disease activity indices (Clinical Disease Activity Index and Van Hees Activity Index) were calculated. In seven patients positive images of colon segments affected by Crohn's colitis were obtained using 99mTc-PEG-liposomes. Only a moderate relation between 99mTc-liposome scan grading and verification procedures was found (Spearman rank r = 0.22). In accordance with previous studies, no significant correlation was found between the clinical disease activity indices and the verification procedures. This study was prematurely terminated because of unacceptable side-effects in 3 out of 9 patients, which occured almost immediately after starting the infusion. The complaints consisted of dyspnea and facial erythema. The symptoms were self-limiting when the infusion was stopped. In conclusion, the extent of Crohn's colitis can be established non-invasively with 99mTc-PEG-liposome scintigraphy. However, in view of the encountered side-effects, the PEG-liposomal preparation may have to be modified.

Adult↗
PubMed1975

[Pharmacological action of cattle prostate extracts (PE). V. Effect on the bladder].

As the extract of cattle prostate (PE) is clinically effective in treating prostatic hypertrophy, a study was carried out on urinary bladders of rat, guinea pig, rabbit and dog as well as on guinea pig ileum. Muscle strip of rat and/or dog bladder contracted with PE with increasing spontaneous movement, and was unaffected by atropine. The isolated ileum of guinea pig also contracted with PE, and the contraction was inhibited by papaverine, but not by atropine. A rise in intravesical pressure was observed with increasing spontaneous movement in guinea pig bladder treated with PE, as well as in rabbit bladder in vitro or in situ. The sphincter vesica of guinea pig was dilated by PE as well as by ACh and methacholine.

Acetylcholine↗
PubMedDate not supplied

The 99mTc-HMPAO leukocyte scan: an alternative to radiology and endoscopy in evaluating the extent and the activity of inflammatory bowel disease.

Seventy-eight patients, 47 with Crohn's disease and 31 with ulcerative colitis, were studied using 99mTc-HMPAO-labelled leukocytes, in order to assess the reliability of the scan in evaluating the location and activity of the disease. The granulocyte integrity was assessed by evaluating the lung wash-out and the early liver and spleen uptake using a 20 minute initial dynamic study. The results of the leukocyte scan revealed a high correlation with radiological and endoscopic findings in the diagnosis of the inflamed bowel segments. The disease activity correlated well with uptake in the bowel, graded from 0 to 3. The leukocyte scan exactly documented the activity in the 9 cases of Crohn's disease located in the ileum and in 5 cases in which the endoscopic exploration was hampered by scarring. Four fistulae were correctly visualized. Moreover, the change in activity after therapy in 6 patients was documented. This technique provides images of excellent quality, superior to those obtainable with indium-111.

Adult↗
PubMed2002

Electrospray ionization fourier transform ion cyclotron resonance mass spectrometry of dissolved organic phosphorus species in a treatment wetland after selective isolation and concentration.

A method for the selective concentration of dissolved organic phosphorus (DOP) from complex surface water samples for the first time allows mass spectral characterization of individual DOP compounds in phosphorus-limited ecosystems. The entire dissolved organic matter (DOM) pool is first separated according to molecular weight by tangential cross-flow ultrafiltration (CFF). DOP is selectively isolated and concentrated from CFF fractions by a barium precipitation procedure. The DOP precipitate is then reconstituted in distilled water and excess barium, and other cations are removed with an ion-exchange resin. The DOP isolation/concentration step can provide up to 15-fold concentration and 300-fold concentration of high molecular weight DOP when combined with the inherent concentration provided by CFF. The procedure also removes cations and most of the background DOM, leaving DOP in a matrix suitable for electrospray ionization and mass spectral characterization. Model organic phosphate standards representative of DOP species expected in aquatic environments were used to evaluate the technique. It was then applied to a series of high molecular weight (>1000) CFF retentates isolated from sites within the Everglades Nutrient Removal (ENR) treatment wetland. The elemental compositions of several individual DOP compounds observed at different sites within the ENR were determined by electrospray ionization Fourier transform ion cyclotron resonance mass spectrometry.

Conservation of Natural Resources↗
PubMed1979

Gas chromatographic method for the determination of valproic acid in human plasma.

A gas chromatographic method has been developed for the routine monitoring of valproic acid (VPA) in human plasma samples. Two compounds, 2-ethylpentanoic acid (EPA) and 2-propylhexanoic acid (PHA), were synthesized and evaluated as internal standards together with cyclohexane carboxylic acid (CHCA), a commonly employed internal standard. Crystalline barium salts of VPA, EPA, and PHA were prepared, which enabled preparation of standard solutions of high accuracy for use in calibration experiments and in daily intra-laboratory quality control tests. The extraction scheme was designed on the basis of the solvent partitioning properties of VPA. Solvent transfers are required in the extraction scheme, but solvent evaporations are not. Studies were made of the performances of EPA, PHA, and CHCA as internal standards in the VPA assay at different lifetimes of the 10% SP-1000 chromatography column. As judged by these studies, EPA or CHCA is a better choice than PHA as an internal standard, provided that certain guidelines are followed in the use of CHCA.

Chromatography, Gas↗
PubMed1996

Detection and characterization of primary liver cancer in rats by MS-264-enhanced MRI.

A new MR contrast agent, MS-264 (Gd(1RS)-1-(p-butylbenzyl)-DTPA), was developed to achieve hepatobiliary specificity and its potential evaluated for detecting and characterizing liver tumors in rats with chemically induced hepatocellular carcinoma (HCC). In seven rats with 66 HCC lesions, enhancements of different abdominal organs and tumors were compared on T1-weighted images after intravenous administration of Gd-DTPA (0.3 mmol/kg) and MS-264 (0.05 mmol/kg). MR images were correlated with postmortem microangiographic and histological findings. An overall enhancement of different organs, which normalized within 24 h, was observed after Gd-DTPA and MS-264 injection. MS-264 caused a higher relative enhancement (RE) in liver (60%), compared with that of Gd-DTPA (40%), which resulted in a prompt negative contrast enhancement in 59 of 66 HCCs. All were moderately to poorly differentiated (Grades II-IV) tumors. Six of these 59 negative contrast-enhancing lesions showed a positively enhanced peritumoral rim, which corresponded histologically to malignant infiltration (n = 2) or compression (n = 4). On the other hand, six well differentiated HCCs showed prolonged positive enhancement. However, one well differentiated HCC was not positively enhanced by MS-264, probably due to poor access of the agent to the lesion. In comparison to that of the precontrast images, enhancement with Gd-DTPA and MS-264 increased the number of detected lesions by 22 and 42%, respectively. In this animal study, MS-264 proved to be useful in detection and characterization of primary liver cancers.

Animals↗
PubMed1988

The effect of known K+-channel blockers on the electrical activity of bovine lymphatic smooth muscle.

The effects of known K+-channel blockers on the electrical properties of bovine lymphatic smooth muscle were investigated using the double sucrose-gap technique. Constant current anodal pulses elicited hyperpolarizing electrotonic potentials (EP's) which were characterised by a "sag" in the potential record. Current/voltage relationship (I/V), which were examined by measuring EP amplitude at the end of 5 s anodal pulses (less than 30 microA), showed an apparent increase in conductance with increasing hyperpolarization. In the presence of caesium (10 mM), 4-aminopyridine (10 mM) or in the absence of external K+ the sag in the EP was lost and the inward rectification characteristic of the control I/V relationship was abolished. Barium (2.5 mM) also abolished in sag in the EP although TEA (10 mM) had no effect on either EP shape or I/V relationship. Thus it would appear that lymphatic smooth muscle shows inward rectification which is slowly activating and is blocked by some of the known K+-channel blockers or by the removal of external K+.

4-Aminopyridine↗
PubMed1994

alpha-Aminoadipic acid blocks the Na(+)-dependent glutamate transport into acutely isolated Müller glial cells from guinea pig retina.

The effect of the glial toxin alpha-aminoadipic acid (AAA) upon the Na+/glutamate cotransporter of acutely isolated guinea pig retinal glial cells was studied using the whole-cell voltage-clamp technique. Glutamate evoked an inward current in these cells at negative holding potentials dependent on the presence of extracellular Na+ and intracellular K+. A reversal potential could not be found for the current. L-trans-Pyrrolidine-2.4-dicarboxylic acid (PDC), a blocker of Na(+)-dependent glutamate uptake, diminished the glutamate current also in our cells. Application of L-AAA also generated an inward current at negative holding potentials, without a reversal potential, being suppressed if extracellular Na+ or intracellular K+ was removed. The glutamate uptake blocker, PDC (200 microM), blocked the L-AAA (1 mM) current. Thus, L-AAA proved to be transported by the Na+/glutamate transporter of Müller cells. Hence, glutamate currents were diminished by L-AAA competitively with a Km of 499 microM at a glutamate concentration of 10 microM. The Na+/glutamate uptake was less sensitive to DL- and D-AAA block. It is suggested that the blocking effect of AAA on Na(+)-dependent glutamate uptake into glial cells might be involved in the well known glia toxicity of this compound.

2-Aminoadipic Acid↗
PubMed1990

Electrophysiological properties of reactive glial cells in the kainate-lesioned hippocampal slice.

Kainate-lesioned hippocampal slices provide an excellent system for examining the electrophysiological properties of non-cultured glial cells without interfering signals from surrounding neurons. Intracellular recordings in the intensely gliotic CA3 region indicated that the resting membrane potential and input resistance of these reactive glial cells were similar to those reported for non-reactive astrocytes. Dye-coupling typical of astrocytes was also demonstrated amongst these cells, and was considerably reduced by cytoplasmic acidification. Occasionally these cells demonstrated spontaneous, rhythmic oscillations of membrane potential associated with large changes in whole cell input resistance. The action potentials reported in cultured astrocytes were not observed in reactive glial cells, even under conditions that maximize the observation of Ca2(+)-dependent responses. This suggests that reactive glial cells in this preparation have either no voltage-activated Ca2+ channels or a very low density of such channels. These cells also lack a bicarbonate conductance, but they do appear to have an apamin-sensitive conductance, possibly a Ca2(+)-activated gK.

Animals↗
PubMed1992

Potassium currents from isolated frog lens epithelial cells.

Using the perforated patch version of whole-cell recording, we have measured currents from isolated frog lens epithelial cells. Three types of currents were seen. A time-independent outwardly rectifying potassium current was identified that sets the resting voltage. This potassium current differs significantly from any of the potassium currents recorded with the whole-cell technique in mammalian lens epithelial cells. In addition to the potassium current, the two other currents present were both outwardly rectifying: one was time-independent while the other showed distinct activation.

Animals↗
PubMed1988

Scintigraphic assessment of bowel involvement and disease activity in Crohn's disease using technetium 99m-hexamethyl propylene amine oxine as leukocyte label.

Using a novel labeling technique with technetium 99m-hexamethyl propylene amine oxine, we studied 29 patients with known or suspected Crohn's disease. Technetium 99m-hexamethyl propylene amine oxine leukocyte scanning (99mTc scan) was prospectively compared with the results of independently performed radiologic, endoscopic, and histologic examinations, and with findings at surgery, to assess the clinical usefulness of this technique to localize inflammatory lesions. In addition, uptake of technetium 99m-hexamethyl propylene amine oxine in the bowel was graded by comparing it with the uptake in liver and bone marrow and correlating this with established parameters of disease activity. The viability of homologous labeled leukocytes was greater than 95%. Less than 5% of lymphocytes were found in the final preparation. It was found that 45% +/- 12% of the label was bound to granulocytes, and 98% of the unbound label was washed off before reinjection. The results of 99mTc scan revealed a good correlation with those of barium enema (r = 0.880, p less than 0.001), of endoscopy/surgery (r = 0.983, p less than 0.001), and of all combined reference methods (r = 0.981, p less than 0.001). Activity as determined by 99mTc scan was weakly correlated with the results of Crohn's disease activity index (r = 0.559, p less than 0.01), van Hees index (r = 0.606, p less than 0.01), and erythrocyte sedimentation rate (r = 0.456, p less than 0.05) in 24 patients with proven Crohn's disease. The correlation was improved when the 99mTc scan was compared with a combination of these activity parameters and C-reactive protein (r = 0.781, p less than 0.001). Extraintestinal manifestations (joints) and complications (cholecystitis) were also identified correctly by the 99mTc scan. The study demonstrates that leukocyte scanning with technetium 99m-hexamethyl propylene amine oxine as a label can reliably assess the location and, to a lesser degree, activity of Crohn's disease. This technique is more convenient and provides images far superior to those produced by indium 111-labeled leukocyte scanning.

Adolescent↗
PubMed1978

Effects of prostaglandins on vesicourethral smooth muscle of rabbit. Therapeutic implications.

The effects of PGF 2-alpha and PGE2 on the vesicourethral smooth muscle of the rabbit were studied in vitro. PGF2-alpha had potent contractile effects on the bladder body and comparatively less in the bladder base and the proximal urethra. PGE2 contractile effects were two times greater than PGF 2-alpha on the bladder body but minimal or absent on the base and the urethra. The effects of PGF2-alpha and PGE2 seem to be mediated through a prostaglandin receptor as indicated by competitive antagonism of both prostaglandins by N-0164, a synthetic phenyl phosphonate. It also appears that the effects of PGF2-alpha PGE2 may not be mediated through muscarinic, adrenergic, nicotinic, or histaminic receptors or direct smooth-muscle action. The therapeutic implications of PGE2 in the patients with problems of bladder emptying are discussed.

Acetylcholine↗
PubMed1993

Persistent muscarinic excitation in guinea-pig olfactory cortex neurons: involvement of a slow post-stimulus afterdepolarizing current.

The persistent excitatory effects of the muscarinic agonist oxotremorine-M were investigated in guinea-pig olfactory cortex neurons in vitro (28-30 degrees C) using a single-microelectrode current-clamp/voltage-clamp technique. In 40% of recorded cells (type 1), bath-application of oxotremorine-M (2-10 microM; 1-2 min) induced a strong membrane depolarization, an increase in input resistance and a sustained neuronal discharge lasting over 30 min following agonist washout. A large depolarizing stimulus applied during the action of oxotremorine-M, evoked a slow post-stimulus afterdepolarization (approximately 10-15 mV) lasting approximately 30 s. Injection of steady negative current at the peak of this response produced a slow repolarization of the membrane potential (half-time approximately 0.6 min) towards a plateau level ("hyperpolarization recovery"); these effects of oxotremorine-M were slowly reversed on washout or by application of atropine (1 microM). In a second population of neurons (type 2; 39% of total), oxotremorine-M produced a large depolarization, a resistance increase and repetitive firing that did not persist after agonist washout; these neurons failed to generate a prominent slow afterdepolarization on stimulation, and showed no hyperpolarization recovery effect. Their resting membrane properties were not significantly different from those of type 1 cells. The remaining proportion of cells (type 3) elicited little or no muscarinic response to oxotremorine-M and no slow afterdepolarization; these cells showed characteristics spike fractionation (pre-potentials) during an evoked train of action potentials.(ABSTRACT TRUNCATED AT 250 WORDS)

4-Aminopyridine↗