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PubMed1989

Hypertension and associated cardiovascular abnormalities induced by chronic barium feeding.

Because high barium concentrations (2-10 ppm) in human drinking water have been reported to be associated with elevated cardiovascular mortality, hypertension and other cardiovascular effects were sought in rats chronically exposed for 1-16 mo to drinking water containing 1, 10, or 100 ppm barium. From weaning, female Long-Evans rats were kept in a "low contamination" environment and fed a diet low in trace metals. Their drinking water was deionized, fortified with 5 essential trace metals, and either 0, 1, 10, or 100 ppm barium was added. Indirect systolic pressure of unanesthetized rats was measured in triplicate at 1, 2, 4, 8, 12, and 16 mo. Average systolic pressure increased significantly after exposure to 100 ppm barium for 1 mo or longer and after exposure to 10 ppm barium for 8 mo or longer. After 4 or 16 mo, barium exposure failed to alter organ weights or tissue concentrations of calcium, magnesium, sodium, or potassium; however, both 10 and 100 ppm barium resulted in significant increases in tissue barium. Rats exposed to 100 ppm Ba for 16 mo exhibited depressed rates of cardiac contraction and depressed electrical excitability in the heart. Hearts from these maximally exposed rats also had significantly lower ATP content and phosphorylation potential, as measured by 31P NMR spectroscopy. Although the barium-induced increase in the blood pressure of rats was modest, comparable mild hypertension in humans would have major health implications.

Animals↗
PubMed1986

Ultrastructural evidence in rabbit ear arteries that barium enters smooth muscle cells through calcium channels.

The calcium channel blocker methoxyverapamil, at 10(-5) mol/l, abolished contractile responses of isolated perfused rabbit ear arteries to barium. Entry of barium into smooth muscle cells was detected by the presence of mitochondrial granules specific for barium. Methoxyverapamil (10(-5) mol/l) prevented the appearance of barium granules. In a further series of experiments, eight out of twelve arteries incubated with barium, 2.5 mmol/l, showed granules; when the incubate contained 2.5 mmol/l of both barium and calcium, granules were found in only one of twelve specimens; thus calcium appears to compete with barium for entry. These results are consistent with the hypothesis that contractile responses to barium depend on entry of barium into the cells through calcium channels.

Animals↗
PubMed1984

Mechanism of action of barium ion on rat aortic smooth muscle.

The mechanism of action of barium ion on the aortic smooth muscle of the normal rat was investigated using in vitro calcium-depleted aortic strips. Aortic strips were depleted of calcium by repeated exposure to norepinephrine in a calcium-free bathing solution. Although calcium depletion abrogated the response of strips to catecholamines and depolarizing agents, the response to barium chloride remained quantitatively intact. The calcium influx blocker D 600 prevented the contractile response to barium but not to catecholamines, whereas phentolamine prevented the response to catecholamines but not barium. The strip response to barium was depressed by a twofold increase in extracellular magnesium concentration whether the strip was intact or calcium depleted. Although increased concentrations of calcium in the extracellular medium inhibited the contractile response to potassium ion, increases in barium merely potentiated the potassium contracture. These findings indicate that barium produces its contractile effect on vascular smooth muscle by a direct intracellular interaction with the contractile or regulatory proteins. Barium enters these cells via calcium influx channels and is probably not sequestered in a physiologically releasable pool. Unlike calcium, barium does not stabilize the smooth muscle sarcolemma when present in high concentration.

Animals↗
PubMed1989

The effect of high- vs low-density barium preparations on the quantitative features of swallowing.

We compared the effect of high-density and low-density barium preparations on the quantitative features of swallowing. The two barium preparations differed primarily in density but also differed somewhat in viscosity. Concurrent videofluoroscopic and manometric studies were done in nine healthy control subjects. Videofluoroscopy was recorded in the lateral projection at 30 frames/sec while concurrent manometry was done with five intraluminal transducers that straddled the pharynx and upper esophageal sphincter. Swallows of 5 and 10 ml of high- and low-density barium preparations were recorded. Analysis indicated that, compared with the low-density barium (1.4 g/cm3), the high-density barium (2.5 g/cm3) preparation had a slower oral and pharyngeal bolus transit time and caused significant quantitative differences in the function of the upper esophageal sphincter. Compared with low-density barium boluses, the high-density barium boluses were associated with later sphincter opening and closure, longer duration of sphincter opening and flow, lower flow rate, greater maximal anterior hyoid movement, greater sagittal sphincter diameter, and higher intrabolus pressure upstream of and within the sphincter. We conclude that the density as well as the viscosity of the barium preparation used in radiologic examination of the oral-pharyngeal phases of swallowing has an influence on bolus transit time through the mouth and pharynx, and on the quantitative features of upper esophageal sphincter opening. Although these quantitative differences cannot generally be recognized visually at fluoroscopy, they become important for the quantitative assessment of swallowing in patients with suspected disorders of oral-pharyngeal swallowing. Therefore, the basic barium preparations used to examine such patients should be either standardized or at least specified.

Adult↗
PubMed1997

Timed barium swallow: a simple technique for evaluating esophageal emptying in patients with achalasia.

OBJECTIVE: Our purpose was to define a simple technique for timing a barium swallow by which radiologists can assess esophageal emptying in patients with achalasia before and after minimally invasive therapy. Our purpose was also to determine the best method of quantifying the degree of emptying using this timed technique. MATERIALS AND METHODS: In the barium swallow technique, upright frontal spot films of the esophagus are obtained at 1, 2, and 5 min after ingestion of 100-200 ml of low-density (45% weight in volume) barium sulfate (volume of barium determined by patient tolerance). Forty-two of these barium swallows done by 23 patients with achalasia were retrospectively reviewed. The examination served either as a baseline study or as a 1-month follow-up study after patients had undergone pneumatic dilatation or Clostridium botulinum toxin injection. The spot films were digitized, and a region of interest was drawn around the column of barium by two observers. The change in area seen in the region of interest on the 1- and 5-min films served as the gold standard for percentage of emptying. The spot films were then analyzed by four other observers, each of whom independently, subjectively, and qualitatively estimated the percentage of emptying between the 1- and 5-min spot films. Percentages were divided into quintiles. On a separate occasion, each of these four observers also independently measured the height and width of the barium column on the 1- and 5-min spot films. The product of height times width seen on the 1- and 5-min films became the quantitative estimate for percentage of emptying. RESULTS: We found no statistically significant difference between the percentage of emptying as measured on the digitized images by the two observers and the height-times-width calculations or qualitative emptying percentage as estimated by the four observers. Interobserver agreement for the area evaluated on the digitized films as well as the height-times-width measurements and qualitative estimates of emptying was almost perfect (the correlation coefficients being 0.99, 0.87, and 0.93, respectively). CONCLUSION: The timed barium swallow is a simple and reproducible technique. Both qualitative assessment and estimated change in area based on height-times-width measurements of the barium column are accurate methods of estimating esophageal emptying.

Adolescent↗
PubMed1995

Relationship between particle size of barium glass filler and water sorption of light-cured composite resin.

The reaction of barium glass filler with water was determined by investigation of the effects of the particle size of barium glass filler on the water sorption rate and the mechanical properties of composite resin. Barium glass and quartz were milled to obtain powders with different average particle sizes. These powders were silanized and used as inorganic filler in composite resin. Photoactivated base monomer was loaded at 65% (w/w) with these fillers to prepare the composite resin paste. The water sorption of barium glass filled resin was always more than that of quartz filled resin. The amount of sorbed water obtained by barium glass filled resin increased as the particle size decreased. The particle size of the quartz filler did not affect the water sorption. The flexural strength of barium filled resin decreased after water immersion more than that of the quartz filled resin as the particle size decreased. These results suggest that the water durability of barium glass is low and the surface of barium glass filler is damaged by water. Water would be retained in the interface between the barium glass filler and the matrix resin.

Absorption↗
PubMed2003

Effects of powdered versus liquid barium on the viscosity of fluids used in modified swallow studies.

OBJECTIVE: To determine if the viscosity of thickened juice mixtures used in modified barium swallow studies significantly changes with the addition of powdered barium. We also describe a test formulation created using liquid barium, which has a negligible effect on juice viscosity. METHODS: The viscosities of water and standardized honey- and nectar-consistency juices mixed with different amounts of powdered barium were measured by timing the laminar flow of a given initial hydrostatic head of fluid under gravity though an orifice of fixed diameter. Standardized juices were then mixed with a liquid formulation of barium and with measured quantities of water to produce viscosities that more closely equated with those of the standardized juices. RESULTS: With the addition of powdered barium, viscosity increased in all fluids, most markedly with the nectar-consistency juice. Liquid barium formulations maintained the viscosities of the original thickened juices. CONCLUSION: Rendering juices radio-opaque with barium powder results in dramatic increases in the viscosity of the resulting mixture and compromises diagnostic accuracy. Liquid barium preparations have the advantage that they can be rapidly and accurately dispensed by syringe, and their use does not significantly increase the viscosity of the preparation.

Barium Sulfate↗
PubMed1986

Cardiotoxic and bronchoconstrictor effects of industrial metal fumes containing barium.

For certain metal arc-welding and other metal processing operations, compounds of barium are used as flux components. Airborne fumes generated by welding with electrodes using barium fluoride or carbonate fluxes may contain 15-30% of barium in readily water-soluble form (Dare et al. 1984). Urine of welders inhaling such fumes was shown to contain elevated levels of barium ions (up to 234 micrograms/l). To assess the possible hazards of such exposure, the toxic potencies of fume samples, expressed in terms of their water-soluble barium ion contents, were compared with effects of solutions of barium salts in anaesthetised guinea-pigs. Dose-effect relationships were established and it was verified that acute toxic effects of inhaled aerosols or of intravenous bolus administration correlated with the barium contents of various forms of welding fumes. Bronchopulmonary reactivity to the barium was observed as marked increases in resistance to ventilatory air-flow, indicating bronchoconstriction. Simultaneously, marked pressor effects on blood pressure occurred. ECG abnormalities indicated myocardial hyperexcitability. Effects were modified by nifedipine and propranolol pretreatments.

Air Pollutants, Occupational↗
PubMed1991

Biliary excretion of barium in the rat.

Biliary excretion of barium was studied in Sprague-Dawley bile-duct-cannulated rats injected intravenously with 1.8 micrograms Ba/rat as 133Ba-labeled barium chloride. Approximately 0.5% of the barium dose was excreted into bile within 2 h. The time-course profile of biliary excretion of the radiotracer closely reflected that of plasma concentrations. Biliary barium levels reached their peak in the first 15-min period after administration and rapidly declined thereafter. The plasma-to-bile barium-concentration ratio was approx 1 at 2 h after injection. There was no tendency of barium to concentrate in liver, and the 133Ba levels in stomach and small intestine largely exceeded hepatic levels. There is evidence indicating that barium is predominantly excreted with feces following parenteral administration in rats and humans. The results of this study suggest that biliary excretion is of little quantitative importance and that physiological routes other than bile contribute to elimination of barium by the digestive tract.

Animals↗
PubMedDate not supplied

Barium trapping in rectoceles: are we trapped by the wrong definition?

BACKGROUND: Barium trapping within a rectocele is a criterion used by surgeons to select which patients with rectoceles should undergo operative repair. This proctographic study compared the presence and depth of barium trapping within a rectocele on postevacuation radiography with those seen on posttoilet radiography after further evacuation in the privacy of the bathroom. METHODS: Eighty-two consecutive patients with evidence of barium trapping on postevacuation radiographs of a fluoroscopic dynamic cystoproctographic examination were reviewed retrospectively. The size of the rectoceles and the depth of barium trapping on the postevacuation and subsequent posttoilet radiographs were measured. RESULTS: The posttoilet radiographs showed resolution of the barium trapping in 47 (57%) of the 82 patients. Resolution of the trapping was directly related to rectocele size. The mean differences in the depth of barium trapping between the postevacuation and posttoilet radiographs were significant for all sizes of rectocele. CONCLUSION: Barium trapping in rectoceles changes with the degree of rectal evacuation. More complete evacuation was shown on the posttoilet radiograph than on the postevacuation radiograph. Consequently, the posttoilet radiograph may be more appropriate for the preoperative assessment of barium trapping within rectoceles.

Barium Sulfate↗
PubMed2006

Rectal perforations after barium enema: a review.

PURPOSE: Rectal injuries during barium enema are rare but life-threatening complications. The last review about this subject was published more than ten years ago. In the present review, we present an overview on the subject and especially focus on changes in treatment strategies and developments of less risky visualization techniques. METHODS: A literature search was performed in the PubMed library using the key words-barium enema, complications, peritonitis, and rectal perforation-as well as related articles and other references obtained from these articles. RESULTS: The most frequent cause of perforation is iatrogenic and catheter-related. Other causes are related to weakness of the colorectal wall or obstruction. Five types of perforations have been described: 1) perforations of the anal canal below the levator; 2) incomplete perforations; 3) perforations into the retroperitoneum; 4) transmural perforations into adjacent viscera; 5) perforations into the free intraperitoneal cavity. Most incomplete perforations and one-half of the retroperitoneal perforations have minimal clinical signs. Intraperitoneal perforations lead to the most catastrophic course, starting with rectal bleeding and mild abdominal complaints. This is rapidly followed by progressive sepsis and peritonitis, and leads to a high mortality rate. Surgery is not always required for intramural or small retroperitoneal perforations. These can be treated conservatively and require surgical debridement only in case of large amounts of extravasation or abscesses. Surgical repair of large rectal mucosal lesions or anal sphincter lesions is advised. Perirectal abscesses require drainage. Intraperitoneal perforations with gross extravasation need immediate aggressive surgical treatment in a critical care setting, because the threat of shock is high. Intraperitoneal perforations, neglected perforations, gross barium extravasation, poorly prepared colon, and venous intravasation of barium are prognostically unfavorable. The severest late complication in intraperitoneal perforations is ileus. Meticulous technical performance of the barium enema is the most important factor in prevention. CONCLUSIONS: Rectal perforations after barium enema are rare. The overall mortality rate decreased in recent decades from approximately 50 to 35 percent as the result of advances in supportive and intensive care. Because of these advances, more aggressive surgical strategies were undertaken. With the advent of endoscopy, less barium enemas are performed. Consequently, the absolute incidence of complications has decreased. It is expected that in the future barium enemas will be replaced by more sensitive and less risky techniques, such as CT colonography and magnetic resonance colonography.

Barium Sulfate↗
PubMed1983

Barium-induced spontaneous activity in sheep cardiac Purkinje cells.

We used intracellular microelectrodes to study the electrophysiological effects of low barium concentrations (1--4 x 10(-5) M) on sheep cardiac Purkinje fibers. The main effect of barium was an increase in action potential duration (APD) both at -60 mV (APD-60) and at 100% repolarization (APD100). The prolongation of APD was greater at a lower (30/min) than at a higher driving rate (120/min). Barium significantly modified the normal linear relationship between driving rate and APD. The effects of barium on APD were enhanced by lowering [K+]0 and antagonized by increasing [Ca2+]0. Barium caused a slowing of phase 3 repolarization, a steepening of diastolic depolarization and induced spontaneous activity in the resting potential range during the interruption of the drive. The first spontaneous action potential was usually preceded by an oscillatory potential. By means of several procedures (lowering [K+]0, increasing [Ca2+]0, increasing the driving rate) it was possible to identify two separate mechanism underlying the initiation of spontaneous activity: (1) enhancement of normal diastolic depolarization and (2) induction of oscillatory afterpotentials. Finally, barium induced repetitive activity through early afterdepolarizations. We conclude that in Purkinje fibers low barium concentrations cause a lengthening of APD and can induce spontaneous activity by means of at least three different mechanisms. The main factor underlying the barium effects seems to be a reduction in potassium conductance.

Action Potentials↗
PubMed1988

Endoscopy versus double-contrast barium enema in the evaluation of patients with symptoms suggestive of colorectal carcinoma.

Two hundred seventy-six patients with positive findings on a stool guaiac test, hematochezia, a change in bowel habits, or a family history of colorectal carcinoma were referred to the colorectal clinic for further investigation. There were 105 men and 171 women. All patients underwent examination with the 65 cm flexible sigmoidoscope. Patients with no abnormalities on endoscopy underwent a double-contrast barium enema. If the barium enema revealed a polyp or other suspicious pathologic process, the patient was referred for colonoscopy. In 258 patients, findings of barium enema and flexible sigmoidoscopy were in agreement. The findings in 178 of these examinations were completely negative, and in the remaining 80 cases flexible endoscopy and barium enema revealed diverticulosis. In an additional 18 patients, negative findings on flexible sigmoidoscopy were followed by positive findings on barium enema. Thirteen of these 18 patients (72 percent) had negative findings on colonoscopies and therefore had false-positive findings on barium enema. In the remaining five patients (28 percent), an unsuspected colonic carcinoma or premalignant polyp was discovered on barium enema and documented by colonoscopy. Also, in four of these five patients, colonoscopy found additional polyps that were not seen on barium enema.

Barium Sulfate↗
PubMed1997

Relative sensitivity of colonoscopy and barium enema for detection of colorectal cancer in clinical practice.

BACKGROUND & AIMS: The relative sensitivities of barium enema and colonoscopy for colorectal cancer are still debated. The aim of this study was to determine the relative sensitivity of barium enema and colonoscopy in general clinical practice. METHODS: Medical records of 2193 consecutive colorectal cancer cases identified in 20 central Indiana hospitals were reviewed. All procedures performed within 3 years of the diagnosis were identified. RESULTS: The sensitivity of colonoscopy for colorectal cancer (95%) was greater than that for barium enema (82.9%), with an odds ratio of 3.93 for a missed cancer by barium enema compared with colonoscopy. The sensitivity of double-contrast barium enema (85.2%) was not different from that of single-contrast (81.8%). Barium enema performed no better in the right than the left colon. Cancers detected by colonoscopy were more likely to be Dukes' class A (24.9%) than cancers detected by barium enema (9.8%). Colonoscopy performed by gastroenterologists was more sensitive (97.3%) for cancer than colonoscopy by nongastroenterologists (87%), with an odds ratio of 5.36 for a missed cancer by a nongastroenterologist compared with a gastroenterologist. CONCLUSIONS: Hospital quality assurance committees and/or third-party payors should review the sensitivity of barium enema and colonoscopy by practitioners in their institutions. Corrective measures are recommended when sensitivity deviates significantly below the standard set by gastroenterologists performing colonoscopy in this study.

Barium Sulfate↗
PubMedDate not supplied

Quality of air contrast barium enema performed the same day as incomplete colonoscopy with air insufflation.

The quality of 17 air contrast barium enemas performed the same day as incomplete colonoscopies using air insufflation was compared with 21 air contrast barium enemas performed on a different day from incomplete colonoscopies. A gastrointestinal radiologist blinded to the timing of the procedures reviewed the barium studies scoring them as 1 (unsatisfactory) to 4 (excellent) in four areas. The mean overall quality score for the air contrast barium enemas done the same day as incomplete colonoscopy was 3.29 vs. 2.97 for those done on a different day (p = 0.24). There were no significant differences in quality scores between same-day versus different-day air contrast barium enemas for the specific parameters of quality of distention, barium coating, and amount of spasm. We conclude that when colonoscopy using air insufflation is incomplete because of looping or angulation, air contrast barium enema can be done the same day without impairing the quality of the barium study.

Air↗
PubMed1981

Pitfalls in the use of barium enema in early appendicitis in children.

Appendicitis remains the most common intraabdominal indication for surgery in children. Recently, barium enema has been helpful in increasing the accuracy of diagnosis in difficult cases. Experience with 202 barium enemas in children with abdominal pain entertaining the diagnosis of acute appendicitis revealed some of the problems encountered in using this procedure as a diagnostic tool. Of the 66 children who underwent surgery, there were 32 children who were felt to have a positive barium enema and 31 of these turned out to have acute appendicitis. In the group that had negative barium enemas, there were 3 false negatives and 2 of these children had early perforations by the time of their surgery. The third group were equivocal barium enemas and they pointed out the difficulty in obtaining a normal barium enema in a child who does not have appendicitis. It was felt that the use of barium enema as an adjunct was helpful especially if it were positive, but a negative barium enema could not be relied upon to delay surgery in the child with right lower quadrant peritoneal signs.

Acute Disease↗
PubMed2001

Why barium enemas fail to identify colorectal cancers.

BACKGROUND: The aim of the present study was to determine the cause and clinicopathological factors associated with the failure of barium enemas to detect colorectal cancers. METHODS: A histopathological database was used to identify all patients with a diagnosis of colorectal cancer between 1991 and 1995. These records were matched with the records from patients who underwent barium enema examinations between 1990 and 1995. Those patients who had a colorectal cancer histologically diagnosed within 24 months of a barium enema in which no carcinoma was seen, were identified. Where possible the radiology was reviewed. Failure to identify a carcinoma was then attributed to either simple failure, technical, interpretive or perceptive difficulties. RESULTS: There were 967 patients with colorectal cancers treated in Christchurch Hospital during the study period 1991-1995. Matching of these patient details with all barium enema records revealed 313 patients who had barium enemas and histologically proven colorectal cancer. There were 21 (6.7%) patients in whom a carcinoma was missed. Of these, 18 had a barium enema within 8 months of surgery, and three were performed outside this timespan (15, 18 and 28 months, respectively). On review, 11 carcinomas could not be identified (nine due to technical error: poor coating (n = 1), overlapping loops (n = 3), single-contrast enema (n = 4), faecal residue (n = 1)); and seven could be seen on review of the films (two interpretation errors, one technical and perceptive error, and four perceptive errors). In three cases films could not be found for review. In 16 of the 21 missed lesions the patient had a double-contrast barium enema (DCBE) while five patients had single-contrast barium enema (SCBE). The site and stage of missed tumours is presented. CONCLUSIONS: The most common reason for missed tumours was technical. The percentage of missed tumours in each region of the bowel correlates with the known incidence of tumours in each region and with a normal Dukes stage distribution, except in the caecum where the number of missed lesions was higher than expected.

Aged↗
PubMed2000

A comparison of colonoscopy and double-contrast barium enema for surveillance after polypectomy. National Polyp Study Work Group.

BACKGROUND: After patients have undergone colonoscopic polypectomy, it is uncertain whether colonoscopic examination or a barium enema is the better method of surveillance. METHODS: As part of the National Polyp Study, we offered colonoscopic examination and double-contrast barium enema for surveillance to patients with newly diagnosed adenomatous polyps. Although barium enema was performed first, the endoscopist did not know the results. RESULTS: A total of 973 patients underwent one or more colonoscopic examinations for surveillance. In the case of 580 of these patients, we performed 862 paired colonoscopic examinations and barium-enema examinations that met the requirements of the protocol. The findings on barium enema were positive in 222 (26 percent) of the paired examinations, including 139 of the 392 colonoscopic examinations in which one or more polyps were detected (rate of detection, 35 percent; 95 percent confidence interval, 31 to 40 percent). The proportion of examinations in which adenomatous polyps were detected by barium enema colonoscopy was significantly related to the size of the adenomas (P=0.009); the rate was 32 percent for colonoscopic examinations in which the largest adenomas detected were 0.5 cm or less, 53 percent for those in which the largest adenomas detected were 0.6 to 1.0 cm, and 48 percent for those in which the largest adenomas detected exceeded 1.0 cm. Among the 139 paired examinations with positive results on barium enema and negative results on colonoscopic examination in the same location, 19 additional polyps, 12 of which were adenomas, were detected on colonoscopic reexamination. CONCLUSIONS: In patients who have undergone colonoscopic polypectomy, colonoscopic examination is a more effective method of surveillance than double-contrast barium enema.

Adenoma↗