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PubMed1995

Motility disorders of the esophagus: diagnosis with barium-rice administration.

PURPOSE: To evaluate the role of barium-rice administration for a standardized diagnosis of dysphagia and esophageal motility disorders. MATERIALS AND METHODS: Sixty healthy volunteers and 218 patients with various esophageal disorders (achalasia, scleroderma and other connective tissue diseases, neurologic diseases, esophagitis and others) were examined both by a conventional barium study and by a barium-rice study. The barium-rice meal consisted of barium sulfate and boiled rice, mixed half and half. The time required for esophageal clearance of one sip was measured. RESULTS: Normal esophageal transit time in healthy controls was between 5 and 15 s for both methods. In patients, the conventional barium study revealed a prolonged transit time in only 16.5% (36 of the 218 cases). The barium-rice study was abnormal in 51.8% (113 of 218 cases), independent of the underlying disease. The barium-rice study was pathological in 77 of those 182 patients (42.3%) who had normal barium transit time. In 24 patients the radiologic results was confirmed by endoscopy and manometric measurements. CONCLUSIONS: Esophageal motility abnormalities are detected by a barium-rice study with a high sensitivity. With this simple and low-cost method, quantitative and reproducible results can be obtained. Barium-rice administration is a suitable tool for screening and follow-up of patients with dysphagia and esophageal motility disorders.

Adolescent↗
PubMed1993

[Motility disorders of the esophagus--their diagnosis with a rice-barium meal].

UNLABELLED: The purpose of this study was to evaluate the role of a "barium-rice" study for diagnosis of dysphagia and oesophageal motility disorders. MATERIAL AND METHODS: 203 patients with oesophageal motility disorders of various aetiologies were examined by both conventional barium study and a "barium-rice" study. During the latter, oesophageal clearance of a defined mixture of barium sulfate and boiled rice was measured. RESULTS: The conventional barium study revealed prolonged transit time in only 15.8% (32 of 203 cases), whereas barium-rice study was pathological in 50.8% (103 to 203 cases). In 71 of 171 patients (41.5%) with a normal barium study, barium-rice passage was prolonged. In 23 patients, radiological results were confirmed by manometric measurements. CONCLUSION: Oesophageal motility disorders are detected by a barium-rice study with high sensitivity independent of the underlying disease. The barium-rice study offers a simple diagnostic tool revealing quantitative and reliable results. The barium-rice study is a suitable method for screening and follow-up of patients with dysphagia and oesophageal motility disorders.

Adolescent↗
PubMed1984

Alteration of the fast excitatory postsynaptic current by barium in voltage-clamped amphibian sympathetic ganglion cells.

Barium-induced alterations in fast excitatory postsynaptic currents (e.p.s.cs) have been studied in voltage-clamped bullfrog sympathetic ganglion B cells. In the presence of 2-8 mM barium, e.p.s.c. decay was prolonged and in many cells the e.p.s.c. decay phase deviated from a single exponential function. The decay phase in these cases was more accurately described as the sum of two exponential functions. The frequency of occurrence of a complex decay increased both with increasing barium concentration and with hyperpolarization. Miniature e.p.s.c. decay also was prolonged in barium-treated cells. E.p.s.c. amplitude was not markedly affected by barium (2-8 mM) in cells voltage-clamped to -50 mV whereas at -90 mV there was a progressive increase in peak size with increasing barium concentration. In control cells the e.p.s.c.-voltage relationship was linear between -20 and -100 mV; however, this relationship became progressively non-linear with membrane hyperpolarization in barium-treated cells. The e.p.s.c. reversal potential was shifted to a more negative value in the presence of barium. There was a voltage-dependent increase in charge movement during the e.p.s.c. in barium-treated cells which was not present in control cells. We conclude that the voltage-dependent alteration in e.p.s.c. decay time course, peak amplitude and charge movement in barium-treated cells is due to a direct postsynaptic action of barium on the kinetics of receptor-channel gating in postganglionic sympathetic neurones.

Action Potentials↗
PubMedDate not supplied

Role of double-contrast barium enema in colorectal cancer screening based on fecal occult blood.

AIMS AND BACKGROUND: Screening for colorectal cancer by fecal occult-blood testing has been shown to be effective in reducing colorectal cancer mortality. Total colonoscopy is the test of choice for the assessment of fecal occult blood-positive subjects. Double-contrast barium enema is commonly employed to study the rest of the colon when colonoscopy is incomplete. The present study evaluated the contribution of double-contrast barium enema in detecting neoplastic lesions of the colon in fecal occult-blood-positive subjects with incomplete colonoscopy. METHODS: In the frame of a screening program for colorectal cancer in the Florence District, a new immunochemical fecal occult-blood test replaced the classic guaiac fecal occult-blood test in 1993. Subjects with a positive fecal occult-blood test were invited to undergo total colonoscopy. Incomplete colonoscopy prompted double-contrast barium enema. Type and rate of neoplastic lesions detected by endoscopy or double-contrast barium enema as single methods or combined were evaluated. RESULTS: A total of 38,829 subjects underwent fecal occult-blood testing in the period 1993-2000. Overall, 1,542 were positive. Assessment was refused by 235 subjects. Out of 1,307 subjects accepting assessment, total colonoscopy was attempted in 1,294: of these, it was not possible in 343 cases, and double-contrast barium enema was advised and performed in 261 subjects. Colorectal cancer was detected in 115 subjects, single or multiple adenomas in 323, hyperplastic polyps in 58, inflammatory, hamartomatous or not histologically confirmed polyps in 38, and other benign non-polypoid findings or no abnormality in 773. There were significant differences between the rates of detected colorectal cancers or adenomas of total and incomplete colonoscopy. There were also significant differences between incomplete colonoscopy and the combination of incomplete colonoscopy and double-contrast barium enema as regards rates of detected colorectal cancer, and between total colonoscopy and the combination of incomplete colonoscopy with double-contrast barium enema as regards rates of detected adenomas. Double-contrast barium enema associated to incomplete colonoscopy was responsible for an increase in detection rates of cancer or adenoma of 2.3/1000 or 3.8/1000, respectively. CONCLUSIONS: Double-contrast barium enema was useful in detecting colorectal cancer beyond the range reached by incomplete colonoscopy, whereas our data confirmed a lower sensitivity of double-contrast barium enema for polyps. The diagnostic contribution observed in the present survey confirms the opportunity of performing double-contrast barium enema as a routine adjunct to incomplete colonoscopy. Nevertheless, in order to maximize the detection rate of adenomas, the rate of total colonoscopy should be kept as high as possible.

Adenoma↗
PubMed1981

Retained barium n the appendix: diagnostic and clinical significance.

The significance of prolonged retention of barium in the appendix in an asymptomatic patient has been debated. Four patients, with retained barium in the appendix for several months after gastrointestinal barium studies, who then developed acute appendicitis, are reported and analyzed. Thirty-one patients who retained appendiceal barium longer than 72 hr after radiographic examination of the gastrointestinal tract were followed for over 1 year. No patient developed appendicitis. Five patients underwent abdominal surgery for other indications and there was no evidence of appendicitis. In 11 patients, who had abdominal radiographs 6 days to 4 months after detection of appendiceal barium, the barium had disappeared. The connotation of the term "barium appendicitis" as initially reported is questioned. Preliminary data in this report suggest that no causal relationship exists between prolonged retention of barium and future acute appendicitis and that normal appendices can expel barium in variable time periods. Etiologic connotation between prolonged appendiceal barium retention and future acute appendicitis should be erased. Retained barium in the appendix can be used as an acid in the precise radiographic diagnosis of acute appendicitis.

Adult↗
PubMed1996

Order in disorder: effect of barium on ventricular fibrillation.

BACKGROUND: Drugs that prolong cardiac refractoriness can decrease defibrillation energy requirements. In particular, barium, a relatively selective blocker of cardiac Ik1 channels, produces marked decreases in defibrillation energy. The mechanism of this effect is unknown, and may relate to modulation of the effect of defibrillatory shocks, or an alteration of the pattern of ventricular fibrillation (VF) by the drug. METHODS AND RESULTS: Accordingly, the effect of barium chloride was examined, 1.1 mg/kg followed by 0.1 mg/kg/min intravenously, or saline control, on the pattern of unipolar electrograms using a 120 electrode array, during 73 episodes of VF (37 after saline, 36 after barium ). For each episode of VF, peak-dV/dt associated with local activations and mean activation-activation (ACT-ACT) intervals for the last 2 s of a 10 s episode of VF were measured for each electrode. 'Organization' in VF was measured by the variability in ACT-ACT intervals, their visually assessed pattern, and the relation between local activations on adjacent electrodes. Voltage gradients were measured at each of 40 epicardial sites for each defibrillation shock, delivered at voltages ranging from to 20% to 100% successful in defibrillation. At identical voltage shocks (400 V), mean voltage gradients before and after barium were similar: 18+/-9 and 19+/-1.2 V/cm, respectively. Mean peak -dV/dt for all activations was -8.7+/-0.5 V/s before and -7.7+/-2.8 V/s after barium, suggesting no apparent change in local conduction velocity. When the lowest voltage gradient at any site was less than 3.5 V/cm, defibrillation was successful 14% of the time (two of 14 ) during control, but 88% of the time (14 to 16) after barium infusion (P<0.01). Mean ACT-ACT intervals after barium for all episodes over all electrodes was 107.5+/-14.1 ms, significantly longer than 89.7 +/-3.9 ms after saline, indicating a 20% increase in the cycle length of fibrillation. During saline control, local epicardial electrogram patterns showed irregular, variable morphology electrograms and a mean lowest SD of ACT-ACT intervals over any electrode of 5.1+/-1.5 ms, compared with 1.2+/-0.7 ms after barium (P < 0.0001). Following barium, most unipolar epicardial electrograms showed regular, phasic activations that appear to reflect an organized, uniformly repetitive local activation pattern, suggesting spatially homogeneous and temporally regular activation wavefronts. CONCLUSIONS: During VF after barium, despite an apparently disorganized surface electrocardiographic pattern, epicardial electrogram patterns are altered and reflect a more ¿ordered', homogeneous and regular local activation. This increased order may be in part responsible for the decreased defibrillation energy requirements observed after barium.

Animals↗
PubMed2000

Effects of barium on stimulus-induced rises of [K+]o in human epileptic non-sclerotic and sclerotic hippocampal area CA1.

In the hippocampus of patients with therapy-refractory temporal lobe epilepsy, glial cells of area CA1 might be less able to take up potassium ions via barium-sensitive inwardly rectifying and voltage-independent potassium channels. Using ion-selective microelectrodes we investigated the effects of barium on rises in [K+]o induced by repetitive alvear stimulation in slices from surgically removed hippocampi with and without Ammon's horn sclerosis (AHS and non-AHS). In non-AHS tissue, barium augmented rises in [K+]o by 147% and prolonged the half time of recovery by 90%. The barium effect was reversible, concentration dependent, and persisted in the presence of alpha-amino-3-hydroxy-5-methyl-4-isoxazolepropionate (AMPA), N-methyl-D-aspartate (NMDA) and gamma-aminobutyric acid [GABA(A)] receptor antagonists. In AHS tissue, barium caused a decrease in the baseline level of [K+]o. In contrast to non-AHS slices, in AHS slices with intact synaptic transmission, barium had no effect on the stimulus-induced rises of [K+]o, and the half time of recovery from the rise was less prolonged (by 57%). Under conditions of blocked synaptic transmission, barium augmented stimulus-induced rises in [K+]o, but only by 40%. In both tissues, barium significantly reduced negative slow-field potentials following repetitive stimulation but did not alter the mean population spike amplitude. The findings suggest a significant contribution of glial barium-sensitive K+-channels to K+-buffering in non-AHS tissue and an impairment of glial barium-sensitive K+-uptake in AHS tissue.

2-Amino-5-phosphonovalerate↗
PubMed1997

Preliminary assessment of potential health hazards associated with barium leached from glazed ceramicware.

Ceramic glazes contain several elements which have the potential to leach into food or beverages that are held or stored in ceramicware. Recently, barium salts have been investigated as one of the alternatives to lead in frit formulations for glazes. This preliminary evaluation addresses the potential health hazards associated with barium at levels that might leach from glazed ceramicware. A set of specialty ceramicware, consisting of five teacups and a pitcher, was examined for extractable barium. Exposure to barium that adults (18-44 years) might encounter using the vessels for coffee, tea, or orange juice was estimated. The exposure estimate was derived from values for intakes of the beverages and for the barium migration from glazed ceramicware test samples. An established reference dose (RfD) for barium exposure for the critical effect of hypertension was identified. The potential hazard associated with the leaching of barium from glazed ceramicware varied with the level of use. Consuming beverages in amounts up to the 95th percentile would not result in total barium intake in amounts that exceed the RfD; consuming large quantities (> 95th percentile) of beverages such as tea or coffee from glazed vessels might. This suggests that for a small portion of the population of users, intake of barium may be in quantities that warrant further consideration as a potential health hazard. Analyses of a broad sample of ceramicware and study of barium leaching behaviour under actual use conditions are needed to assess further the significance of these findings.

Adolescent↗
PubMed1966

Endotrophic calcium, strontium, and barium spores of Bacillus megaterium and Bacillus cereus.

Foerster, Harold F. (The University of Texas, Austin), and J. W. Foster. Endotrophic calcium, strontium, and barium spores of Bacillus megaterium and Bacillus cereus. J. Bacteriol. 91:1333-1345. 1966.-Spores were produced by washed vegetative cells suspended in deionized water supplemented with CaCl(2), SrCl(2), or BaCl(2). Normal, refractile spores were produced in each case; a portion of the barium spores lost refractility and darkened. Thin-section electron micrographs revealed no apparent anatomical differences among the three types of spores. Analyses revealed that the different spore types were enriched specifically in the metal to which they were exposed during sporogenesis. The calcium content of the strontium and the barium spores was very small. From binary equimolar mixtures of the metal salts, endotrophic spores accumulated both metals to nearly the same extent. Viability of the barium spores was considerably less than that of the other two types. Strontium and barium spores were heat-resistant; however, calcium was essential for maximal heat resistance. Significant differences existed in the rates of germination; calcium spores germinated fastest, strontium spores were slower, and barium spores were slowest. Calcium-barium and calcium-strontium spores germinated readily. Endotrophic calcium and strontium spores germinated without the prior heat activation essential for growth spores. Chemical germination of the different metal-type spores with n-dodecylamine took place at the same relative rates as physiological germination. Heat-induced release of dipicolinic acid occurred much faster with barium and strontium spores than with calcium spores. The washed "coat fraction" from disrupted spores contained little of the spore calcium but most of the spore barium. The metal in this fraction was released by dilute acid. The demineralized coats reabsorbed calcium and barium at neutral pH.

Acids↗
PubMed2000

Characterization with barium of potassium currents in turtle retinal Müller cells.

Müller cells are highly permeable to potassium ions and play a crucial role in maintaining potassium homeostasis in the vertebrate retina. The potassium current found in turtle Müller cells consists of two components: an inwardly rectifying component and a linear, passive component. These currents are insensitive to broadband potassium channel blockers, tetraethylammonium (TEA) and 4-aminopyridine (4-AP) and well blocked by barium. Differential block by the polyamine spermine suggests that these currents flow through different channels. In this study, we used barium ions as a probe to investigate the properties of these currents by whole cell, voltage-clamp recordings from isolated cells. Current-voltage (I-V) relationships generated from current responses to short (35 ms) and long (3.5 s) voltage pulses were fit with the Hill equation. With extracellular barium, the time course of block and unblock was voltage and concentration dependent and could be fit with single exponential functions and time constants larger than 100 ms. Blocking effects by extracellular barium on the two types of currents were indistinguishable. The decrease of the outward current originates in part due to charge effects. We also found that intracellular barium was an effective blocker of the potassium currents. The relative block of the inward rectifier by intracellular barium suggests the existence of two "apparent" binding sites available for barium within the channel. Under depolarizing conditions favoring the block by internal polyamines, the Hill coefficient for barium binding was 1, indicating a single apparent binding site for barium within the pore of the passive linear conductance. The difference in the steepness of the blocking functions suggests that the potassium currents flow through two different types of channels, an inward rectifier and a linear passive conductance. Last, we consider the use of barium as an intracellular K(+) channel blocker for voltage-clamp experiments.

4-Aminopyridine↗
PubMed2000

Detection of pharyngeal perforation: comparison of aqueous and barium-containing contrast agents.

OBJECTIVE: We sought to assess the value of aqueous and barium-containing contrast agents in the detection of pharyngeal perforation. SUBJECTS AND METHODS: Visual and objective in vitro comparisons of an iodinated aqueous contrast agent, a 50% weight/volume barium suspension, and a 100% weight/volume barium suspension were performed. Moreover, to exclude pharyngeal perforation after surgery, we prospectively examined 109 patients by pharyngography, using the aqueous contrast agent and the 100% weight/volume barium suspension. All patients with a pharyngeal perforation were followed up clinically to exclude complications due to barium application. RESULTS: As opposed to the 100% weight/volume barium suspension, in vitro comparison between the aqueous contrast agent and the 50% weight/volume barium suspension yielded no substantial differences. Seventeen perforations could be detected with the aqueous contrast agent. Although 10 of 17 perforations could be slightly better visualized with the 100% weight/volume barium suspension, two perforations were missed with this agent. Five perforations were equally well detected with both. CONCLUSION: Because of a higher radiopacity, 100% weight/volume barium suspensions may more sharply delineate perforations. However, in contrast to aqueous contrast media, narrow pharyngeal perforations can be missed. Thus, the use of a 100% weight/volume barium suspension does not improve the detection of pharyngeal perforation.

Adult↗
PubMed2003

Comparison of multidetector CT and barium studies of the small bowel: inflammatory bowel disease in children.

OBJECTIVE: We compared barium studies of the small bowel with multidetector CT (MDCT) in the evaluation of the small bowel during the initial presentation of inflammatory bowel disease in a pediatric population. SUBJECTS AND METHODS: This was a prospective study. Eighteen children undergoing workup for inflammatory bowel disease underwent MDCT, colonoscopy, and barium studies of the small bowel before commencement of therapy. Examinations were independently reviewed. The patients and their guardians completed a questionnaire assessing the acceptability of each study. RESULTS: In 13 of 18 children, the findings of MDCT and barium studies of the small bowel concurred in the evaluation of terminal ileum disease. In three of these children, MDCT detected skip segments of small-bowel disease not detected on barium studies of the small bowel. In two of 18 children, the terminal ileum was not visualized on barium studies of the small bowel, whereas MDCT showed substantial terminal ileum disease in both children. In three of 18 children, there was discordance between the two tests regarding terminal ileum disease. However, these discordant imaging findings were all subtle. In addition, MDCT revealed extraenteric abnormalities, clinically relevant in two children (ureteric obstruction and perirectal abscess), and showed the colon in all children, seven of whom had incomplete colonoscopy. The questionnaire revealed that 16 of 18 patients preferred MDCT to small-bowel barium studies. The reasons given were poor tolerance of oral barium and the long duration of barium studies of the small bowel. CONCLUSION: MDCT can be an alternative to barium studies of the small bowel for evaluation of the small bowel in patients with inflammatory bowel disease. MDCT also offers additional, clinically relevant information not obtained by small-bowel barium studies.

Adolescent↗
PubMed1991

Barium sulfate suspension as a negative oral MRI contrast agent: in vitro and human optimization studies.

In vitro proton spectroscopy with line-width measurements and MR imaging were performed on various concentrations of commercially available single contrast (SC), double contrast, oral and rectal barium sulfate suspensions, as well as potassium sulfate, barium chloride, barium hydroxide, and 97% pure barium sulfate suspensions. Approximately 500 ml of 20%, 40%, 60%, and 70% w/w suspensions of SC oral barium sulfate suspensions were administered to four normal volunteers, respectively, and MR images were obtained at both 1.5 T and 0.15 T. Subsequently, 500 ml of 60% w/w suspensions of SC oral barium sulfate suspensions were administered to five normal volunteers and imaged at 1.5 T. All of the inert suspensions produced line-width broadening but the SC oral barium sulfate suspension at 50% and 70% stayed in suspension even after hours of standing undisturbed. As much as 80% of the small bowel and the entire colon were well visualized using the combination of 60% or 70% w/w SC barium sulfate suspensions with SE 550/22 and FISP pulse sequences. The effect was less at 0.15 T and also with the SE 2000/45/90 pulse sequences. We conclude that barium sulfate suspensions are useful as oral MRI contrast agents.

Administration, Oral↗
PubMed1996

Dissolution of Barium from Barite in Sewage Sludges and Cultures of Desulfovibrio desulfuricans.

High concentrations of total barium, ranging from 0.42 to 1.58 mg(middot)g(sup-1) (dry weight) were found in sludges of two sewage treatment plants near Florence, Italy. Barium concentrations in the suspended matter decreased as redox potential values changed from negative to positive. An anoxic sewage sludge sample was aerated, and 30% of the total barium was removed in 24 h. To demonstrate that barium was solubilized from barite by sulfate-reducing bacteria, a strain of Desulfovibrio desulfuricans was used to study the solubilization of barium from barite under laboratory conditions. During cell growth with different concentrations of barite from 0.01 to 0.3 g(middot)liter(sup-1) (the latter is the MIC) as the only source of sulfates in the cultures, the D. desulfuricans strain accumulated barium up to 0.58 (mu)g(middot)mg(sup-1) (dry weight). Three times the quantity of barium was dissolved by bacteria than in the uninoculated medium (control). The unexpectedly low concentration of soluble barium (1.2 mg of Ba(middot)liter(sup-1)) with respect to the quantity expected (109 mg of Ba(middot)liter(sup-1)), calculated on the basis of the free H(inf2)S evolved from the dissimilatory reduction of sulfate from barite, was probably due to the formation of other barium compounds, such as witherite (BaCO(inf3)) and the transient species barium sulfide (BaS). The D. desulfuricans strain, growing on barite, formed visible aggregates. Confocal microscopy analysis showed that aggregates consisted of bacteria and barite. After 3 days of incubation, several autofluorescent crystals surrounded by a dissolution halo were observed. The crystals were identified as BaS by comparison with the commercial compound.

Journal Article↗
PubMed1997

[Scanning electron microscopic studies on mucosal coating by barium mixtures].

The purpose of this study was to observe and evaluate mucosal coating by barium mixtures using electron microscopy. Specimens from the ileum of two pigs, about 50cm in length from the terminal ileum, were divided into 3 groups with different in concentrations and additives of barium mixture. The 50cm length of ileum was cut into 10cm long pieces. Four specimens from each group were evaluated by double contrast study for coating by the barium layer. Then the specimen was frozen with liquid nitrogen solution, and fixed. Afterward, the specimen was cut into about 1cm sections, fixed again, dehydrated, dried, and observed by scanning electron microscopy (SM). In the double contrast study, the differences in barium coating were correlated with the concentration of barium sulphate. The scanning electron microscopic findings were correlated with those of the double contrast study. The various additives in the barium mixture did not cause any distinctive differences. Although barium particles have been studied by electron microscopy, barium mixture coating state on the mucosa of biological materials has not been reported. In conclusion, a correlation of the coated barium layer on double contrast study and the images of scanning electron microscopy was observed using pig ileum specimens.

Animals↗
PubMed1987

Effect of barium meals on gastric electromechanical activity in man. A fluoroscopic-electrogastrographic study.

UNLABELLED: The relationship between the cutaneously recorded electrogastrogram (EGG) and gastric contractions in man is unclear. We investigated: (1) the relationship between the electrogastrogram (EGG) signals and gastric contractions elicited by barium meals and (2) the effects of barium meals on frequency and amplitude of EGG signals. As documented by fluoroscopy in four healthy subjects, barium meals stimulated three per minute gastric peristalsis which corresponded with simultaneously recorded three cycle per minute (cpm) EGG waves. Eighteen other healthy volunteers ingested 45% (w/v) or 60% barium suspensions. As determined by Fourier analysis, the dominant EGG frequency before barium was 3 cpm in 16 subjects; two subjects had no distinct frequency peaks. After barium ingestion, the mean amplitude or power at 3 cpm and 1 cpm increased, but the increase was significant only after 45% barium. IN CONCLUSION: (1) individual EGG waves after barium reflect gastric peristaltic sequences, which are reflected in increases in amplitude or power of 3 cpm EGG activity; (2) density or viscosity of the barium meal affects the gastric myoelectric response; and (3) mechanical correlates of 1 cpm EEG activity are unknown.

Adolescent↗
PubMed2002

Effects of barium, furosemide, ouabaine and 4,4'-diisothiocyanatostilbene-2,2'-disulfonic acid (DIDS) on ionophoretically-induced changes in extracellular potassium concentration in hippocampal slices from rats and from patients with epilepsy.

Glial cells limit local K(+)-accumulation by K(+)-uptake through different mechanisms, sensitive to Ba(2+), ouabaine, furosemide, or DIDS. Since the relative contribution of these mechanisms has not yet been determined, we studied the effects of bath-applied barium (2 mM), ouabaine (9 microM), furosemide (2 mM), and DIDS (1 mM) on ionophoretically-induced rises in [K(+)](o) in the pyramidal layer of area CA1 from normal rat slices, in the presence of glutamate receptor (Glu-R) antagonists. We also investigated the effect of barium on ionophoretically-induced tetrapropylammonium (TPA(+))-signals in order to test for barium-induced changes of the extracellular space. Finally, we repeated the barium experiment on slices from human non-sclerotic and sclerotic hippocampal specimens to assess a reduced glial capability for barium-sensitive K(+)-uptake in sclerotic tissue from epilepsy patients. In normal rat slices barium augmented ionophoretically-induced rises in [K(+)](o) by approximately 120%, also in the presence of tetrodotoxin (TTX) (by approximately 150%), but did not significantly affect the TPA(+)-signal. Ouabaine also augmented the K(+)-signal, but only by 27%. Furosemide and DIDS had negligible effects. In slices from sclerotic human hippocampus an augmentation of the K(+)-signal by barium was absent. Thus barium augments ionophoretically-induced K(+)-signals to a similar extent as previously shown for stimulus-induced signals. We suggest that glial barium-sensitive K(+)-buffer mechanisms reduce fast local rises of [K(+)](o) by at least 50%. This capability of glial cells is extremely reduced in area CA1 of slices from human sclerotic hippocampal specimens.

2-Amino-5-phosphonovalerate↗
PubMed2000

Timed barium esophagogram: A simple physiologic assessment for achalasia.

OBJECTIVE: Success of achalasia therapy is difficult to determine because repeated physiologic study is impractical and symptoms are subjective. Timed barium esophagography directly measures esophageal emptying and is simple to perform. This study (1) evaluates the assessment of myotomy by timed barium esophagography and (2) compares it with premyotomy and postmyotomy symptoms. METHODS: Fifty patients ingested 250 mL low-density barium and had upright films at 1, 2, and 5 minutes premyotomy. Forty-five underwent repeat timed barium esophagography 8 weeks (median) postmyotomy. Premyotomy and postmyotomy height and width of the barium column were compared and related to symptoms. RESULTS: At 1, 2, and 5 minutes premyotomy, median barium column height was 19, 17, and 15 cm, and width was 5.2, 4.8, and 4.5 cm, respectively. Surgery reduced these to 7.0, 5.0, and 1.0 cm and to 3.5, 3.0, and 1.0 cm, respectively (P <.001). Postmyotomy complete esophageal emptying was seen in 29%, 36%, and 49% at 1, 2, and 5 minutes. Postmyotomy height was unrelated (r approximately 0.2) to premyotomy height but was directly related to premyotomy width (r = 0.3-0.5; P <.05); postmyotomy width was directly related to premyotomy width (r approximately 0.6; P <.001). Premyotomy dysphagia was more severe when little change in width occurred from 1 to 5 minutes (r = 0.26, P =.07). Premyotomy regurgitation was more severe the higher the barium column (r approximately 0.4, P <.007). Surgery relieved symptoms in the majority of patients (grade 2-5 dysphagia from 72% to 4%, grade 2-5 regurgitation from 79% to 4%). Postmyotomy symptoms were unrelated to the timed barium esophagogram. CONCLUSIONS: (1) The timed barium esophagogram gives objective confirmation of successful myotomy. (2) Symptoms are unreliable in assessing esophageal emptying.

Barium Sulfate↗