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Biomedical subjects

A H Maurer

Publications and source records attributed to A H Maurer.

At least 19 recordsLinked to original sources
PubMed2006

Regional gastric emptying abnormalities in functional dyspepsia and gastro-oesophageal reflux disease.

To characterize proximal and distal stomach emptying in functional dyspepsia (FD) and gastro-oesophageal reflux disease (GORD). Eighty-three patients underwent gastric emptying (GE) scintigraphy and symptom scoring for the evaluation of upper gastrointestinal symptoms and were divided into three groups: FD (n = 25), GORD (n = 20) and FD + GORD (n = 38). Total, proximal and distal gastric retention were determined scintigraphically and compared with normal controls. Delayed total GE was observed in each subgroup: FD (56%), GORD (45%) and FD + GORD (55%). Greater proximal gastric retention was observed after meal ingestion in GORD compared to FD. Greater distal gastric retention was observed in FD and FD + GORD but it was only mild in GORD. Nausea, vomiting, early satiety, distention and regurgitation were associated with proximal gastric retention whereas there was no symptom associated with distal gastric retention. Multiple regression demonstrated total gastric retention at 30 min and 1 h was positively correlated with regurgitation whereas early proximal gastric retention was positively correlated with regurgitation and negatively correlated with nausea. Selective abnormalities of proximal and distal stomach emptying were demonstrated in GORD and FD. GORD and FD symptoms were associated with proximal gastric retention suggesting that proximal stomach motor function may be important in the pathogenesis of symptoms associated with these disorders.

Adult↗
PubMed2001

Extending gastric emptying scintigraphy from two to four hours detects more patients with gastroparesis.

Gastric emptying scintigraphy (GES) is usually performed for up to 2 hr to measure the gastric emptying (GE) of solids. Symptomatic patients, however, may have borderline results at 2 hr, making it difficult to determine whether a gastric motor disorder is present. The aim of this study was to assess whether extending GES to 4 hr is useful in evaluating patients for gastroparesis and to correlate the results of GES with patient symptoms. We studied 129 patients undergoing GES at Temple University Hospital between July 1998 and March 1999. Solid-phase GE was measured at 0, 0.5, 1, 2, 3, and 4 hr after ingestion of a 99mTc sulfur colloid-labeled egg meal. Dyspeptic symptoms of upper abdominal discomfort, early satiety, postprandial abdominal bloating, nausea, vomiting, and anorexia were graded as none, mild, moderate and severe (0, 1, 2 and 3, respectively) with the sum representing a total symptom score. Of 129 patients, 86 had normal GE at 2 hr; 26 of the 86 normal scans at 2 hr were delayed at 3 hr. Six of the 60 scans normal at 2 and 3 hr were delayed at 4 hr. Of 43 patients with delayed GE at 2 hr, 39 were delayed at 3 hr and 35 were delayed at 4 hr. Overall, the percentage of patients with delayed GE increased from 33% at 2 hr only to 58% using the results of the 2-, 3-, and 4-hr scans (P < 0.05). There was a significantly greater symptom score in patients with delayed GE compared to patients with normal GE (8.4 +/- 0.5 vs 7.1 +/- 0.5; P < 0.05). Conclusion, prolonging GES after ingestion of a 99mTc-labeled egg meal from 2 to 4 hr increased the number of symptomatic patients found to have delayed GE. These results suggest that GES should be performed for up to 4 hrs when the 2-hr result is normal.

Adolescent↗
PubMed2000

Whole gut transit scintigraphy in the clinical evaluation of patients with upper and lower gastrointestinal symptoms.

OBJECTIVE: In a single noninvasive, quantitative test, whole gut transit scintigraphy (WGTS) measures gastric emptying (GE), small bowel transit (SBT), and colonic transit (CT). The aim of this study was to investigate the clinical utility of WGTS in patients with functional gastrointestinal (GI) symptoms. METHODS: A total of 108 patients with either dyspeptic upper GI symptoms (n = 35) or constipation (n = 73) underwent WGTS. Patients consumed a meal of 99 m-Tc egg sandwich with 111-In DTPA in water. They were imaged every 30 min for 6 h to measure GE and SBT, and at 24, 48, and 72 h to measure CT. RESULTS: Of 108 studies, 104 were analyzable. In patients with upper GI symptoms, 14/35 (40%) had delayed GE of solids, 4/35 (11%) delayed SBT, and 11/35 (31%) delayed CT. Of those with constipation, 13/69 (19%) had delayed GE, 5/69 (7%) delayed SBT, and 43/69 (65%) delayed CT. WGTS changed the initial clinical diagnosis in 47/104 (45%) and altered patient management in 70/104 (67%) of the patients. CONCLUSIONS: Transit abnormalities of the upper GI tract and colon are common in patients with functional GI symptoms. Patients with upper GI symptoms frequently have delayed GE, whereas those with constipation tend to have predominantly delayed CT. In many patients with functional GI symptoms, there was evidence of a diffuse GI motility disorder. Whole gut transit scintigraphy is a simple, clinically useful test, as it frequently leads to a change in diagnosis and, therefore, patient management.

Adult↗
PubMed2000

Quantitation of regional ventilation during the washout phase of lung scintigraphy: measurement in patients with severe COPD before and after bilateral lung volume reduction surgery.

STUDY OBJECTIVES: We sought to investigate the effect of lung volume reduction surgery (LVRS) on regional lung ventilation. DESIGN: Retrospective analysis of routinely acquired data before and after LVRS. SETTING: Large, urban, university medical center. PATIENTS: Twenty-nine patients with severe emphysema. INTERVENTION: Bilateral LVRS. MEASUREMENTS AND RESULTS: (133)Xe washout curves during lung scintigraphy exhibit a biphasic pattern (the first component of the washout curve [m(r)] corresponds to an initial rapid phase in washout that reflects larger airways emptying, and the second component [m(s)] reflects a slower phase of washout that is attributed to gas elimination via smaller airways). We analyzed six standardized regions of the lung (upper, mid, and lower zones of the right and left lung), and calculated m(r) and m(s) for each lung region. The mean (+/- SE) baseline FEV(1) was 0.69+/-0.04 L, total lung capacity (TLC) was 139 +/-4% predicted, and the residual volume (RV)/TLC ratio was 65+/-2%. The mean improvement in FEV(1) 3 months post-LVRS was 38%. Post-LVRS, m(r) and m(s) increased in 79 and 74 lung regions, respectively, and there was no relationship with respect to lung regions that had or had not been operated on. The increase in m(s), however, significantly correlated with the increase in FEV(1) (r = 0.66; p<0.0001) and the decrease in RV/TLC (r = -0.67; p<0.0001). An increase in m(s) also correlated with a decrease in PaCO(2) (r = -0.39; p = 0.03), but m(r) showed no relationship with any parameter. CONCLUSIONS: Small airways ventilation in lung regions that had and had not been operated on is associated with a greater improvement in lung mechanics following LVRS.

Administration, Inhalation↗
PubMed2000

Imaging pulmonary emboli and deep venous thrombi with 99mTc-bitistatin, a platelet-binding polypeptide from viper venom.

UNLABELLED: An imaging test that could locate both pulmonary emboli (PE) and their source, active deep venous thrombi (DVT), would be valuable in patient management. Bitistatin, an 83-amino-acid polypeptide isolated from Bitis arietans venom, binds avidly to the glycoprotein IIb/IIIa receptor on platelets. The goal of this study was to label bitistatin with 99mTc and assess its potential for imaging thrombi and emboli in vivo. METHODS: Molecular modeling of bitistatin indicated that its primary amines are located on the opposite side of the molecule from the receptor-binding domain. The primary amines were reacted with succinimidyl-4-hydrazino nicotinate hydrochloride to place 2.4 hydrazino nicotinate (Hn) chelating groups per peptide molecule. Hn-bitistatin was labeled by incubation with 99mTc-glucoheptonate to 96 TBq/mmol and then tested for binding to platelets in vitro and for imaging of 24-h-old DVT and PE in a canine model used previously for other thrombus tracers. RESULTS: 99mTc-Hn-bitistatin bound to stimulated platelets with a dissociation constant (Kd) = 32 nmol/L, similar to that of 125I-bitistatin (Kd = 41 nmol/L). In vivo, focal uptake was observed in planar images as early as 30 min (DVT) and 60 min (PE) after injection. Lesion uptake of 99mTc-Hn-bitistatin at 4 h after injection was calculated in terms of percentage injected dose per gram (%ID/g) of tissue and averaged 0.89 %ID/g PE and 0.79 %ID/g DVT. Lesion-to-background ratios averaged 34:1 (PE-to-lung), 18:1 (DVT-to-blood), and 284:1 (DVT-to-muscle). These values were not significantly different from iodinated bitistatin, but uptakes were higher than other tracers tested in the same model. CONCLUSION: 99mTc-Hn-bitistatin retains the functional activity of the iodinated peptide, has higher DVT and PE uptakes than other thrombus tracers in this standardized model, and has target-to-background characteristics suitable for imaging both PE and DVT in a single test.

Animals↗
PubMed1999

Cholinergic effects on human gastric motility.

BACKGROUND: Cholinergic regulation of chronotropic (frequency) and inotropic (force) aspects of antral contractility and how these impact on gastric emptying are not well delineated. AIMS: To determine the effects of cholinergic stimulation and inhibition on myoelectric, contractile, and emptying parameters of gastric motility. METHODS: Ten normal subjects underwent three studies each, using simultaneous electrogastrography (EGG), antroduodenal manometry, and gastric emptying with dynamic antral scintigraphy (DAS). After 30 minutes of baseline fasting manometry and EGG, subjects received saline intravenously, atropine (0.6 mg then 0.25 mg/hour intravenously), or bethanechol (5 mg subcutaneously). This was followed by another 30 minutes' recording and by three hours of postprandial recording after ingestion of a technetium-99m labelled solid meal. RESULTS: During fasting, atropine decreased, whereas bethanechol increased, the antral manometric motility index and EGG power. Postprandially, atropine decreased the amplitude of antral contractions by DAS, decreased the postprandial antral manometric motility index, and slowed gastric emptying. Atropine caused a slight increase in postprandial frequency of antral contractions by DAS and gastric myoelectrical activity by EGG. Bethanechol slightly increased the amplitude, but slightly decreased the frequency of antral contractions by DAS and decreased the frequency of gastric myoelectrical activity by EGG, with no significant increase in the motility index or gastric emptying. CONCLUSIONS: Cholinergic antagonism with atropine reduces antral contractility and slows gastric emptying. Cholinergic stimulation with bethanechol increases antral contractility, but decreases the frequency of antral contractions, without altering the antral motility index or gastric emptying.

Adult↗
PubMed1998

Effect of gastric acid suppressants on human gastric motility.

BACKGROUND: The effect of histamine H2 receptor antagonists on gastric emptying is controversial. AIMS: To determine the effects of ranitidine, famotidine, and omeprazole on gastric motility and emptying. PATIENTS AND METHODS: Fifteen normal subjects underwent simultaneous antroduodenal manometry, electrogastrography (EGG), and gastric emptying with dynamic antral scintigraphy (DAS). After 30 minutes of fasting manometry and EGG recording, subjects received either intravenous saline, ranitidine, or famotidine, followed by another 30 minutes recording and then three hours of postprandial recording after ingestion of a radiolabelled meal. Images were obtained every 10-15 minutes for three hours to measure gastric emptying and assess antral contractility. Similar testing was performed after omeprazole 20 mg daily for one week. RESULTS: Fasting antral phase III migrating motor complexes (MMCs) were more common after ranitidine (9/15 subjects, 60%), famotidine (12/15, 80%), and omeprazole (8/12, 67%) compared with placebo (4/14, 29%; p < 0.05). Postprandially, ranitidine, famotidine, and omeprazole slowed gastric emptying, increased the amplitude of DAS contractions, increased the EGG power, and increased the antral manometric motility index. CONCLUSIONS: Suppression of gastric acid secretion with therapeutic doses of gastric acid suppressants is associated with delayed gastric emptying but increased antral motility.

Adolescent↗
PubMed1998

Effects of in vitro versus in vivo red cell labeling on image quality in gastrointestinal bleeding studies.

OBJECTIVE: Both in vivo and in vitro red cell labeling methods are available for performing gastrointestinal bleeding studies. While in vitro labeling has been shown to result in higher binding efficiency, no comparison of clinical image quality has been reported between those techniques. This study compares in vivo and in vitro methods using both subjective and objective measurements of image quality. METHODS: A consecutive series of gastrointestinal bleeding studies performed on 23 patients using in vivo labeling was compared to a series of 23 studies using in vitro labeling. Images at 30 min postinjection were randomized and analyzed by two observers. Subjective evaluation of image quality, as well as renal activity, was based on a comparison of femoral vein and inferior vena cava activity to adjacent background using numerical scores with a scale of 0-3. Image quality using the subjective scores was further classified as acceptable and poor. Target-to-background measurements of femoral vein to adjacent soft tissue in the thigh and inferior vena cava to adjacent abdominal background also were made. RESULTS: In vitro label subjective image quality was acceptable in 87% and 91% of cases for vascular and renal activity, respectively, but only 35% and 52% for in vivo labeling. In vitro label target-to-background ratios were significantly better than in vivo label for the femoral vein and inferior vena cava, as well as for the subjective assessment of vascular image quality, but not for renal activity. CONCLUSION: In vitro red cell labeling improves clinical image quality as compared with in vivo labeling. Both subjective and objective measurements of image quality are useful for comparing the results of labeling methods.

Abdomen↗
PubMed1998

In vitro platelet binding compared with in vivo thrombus imaging using alpha(IIb)beta3-targeted radioligands.

Radioligands for the alpha(IIb)beta3 integrin on platelets are being studied for their ability to image venous thrombi and pulmonary emboli. One such radioligand, 123I-bitistatin, was previously shown to have higher thrombotic uptake in an animal model than other disintegrins, but the reason for this difference was not clear. The purpose of this study was to evaluate three labeled disintegrins, bitistatin, kistrin and barbourin, to look for in vitro differences in platelet binding which could explain the in vivo behavior. Disintegrins labeled with 121I were compared in vitro for extent of binding to platelets and rates of binding and dissociation. These findings were related to organ distribution and image quality for imaging thrombotic lesions, following administration of 123I-disintegrins in an animal model. Fibrinogen at 8.8 micromol/l was able to displace 125I-barbourin and 125I-kistrin more rapidly from ADP-stimulated platelets, with half-times of 3.5 and 10.7 min, compared with 125I-bitistatin (31.6 min). At equivalent concentrations in whole blood, a higher percentage of bitistatin bound to platelets compared with the other two. In vivo, kistrin and barbourin had significantly lower thrombus:muscle and pulmonary embolus:lung ratios in images compared with bitistatin. There was evidence of more metabolic deiodination of labeled kistrin and barbourin in vivo compared with bitistatin. A surprising finding was that conventional in vitro platelet binding studies did not predict the relative in vivo behavior of labeled disintegrins. The results suggest that labeled bitistatin has improved targeting of thrombi because it is less easily displaced from stimulated platelets, permitting longer lesion retention. It also appears to have a greater association with resting platelets in the blood, which may increase bioavailability and delay metabolic breakdown.

Animal Testing Alternatives↗
PubMed1997

Comparison of scintigraphy and lactulose breath hydrogen test for assessment of orocecal transit: lactulose accelerates small bowel transit.

UNLABELLED: The lactulose breath test (LBT) and gastroenterocolonic scintigraphy (GECS) can both be used to measure orocecal transit time (OCTT). The aims of this study were (1) to measure OCTT by LBT and GECS and (2) to determine whether lactulose alters orocecal transit. METHODS: Eight normal subjects underwent simultaneous breath hydrogen testing, GECS, and duodenal manometry while receiving either 10 g lactulose or placebo with a radiolabeled solid/liquid test meal during two studies. There was a good correlation between OCTT by LBT and GECS when performed simultaneously (r = 0.95; P < 0.001). OCTT by GECS with lactulose was significantly faster (P = 0.004) than by GECS without lactulose, despite no change in gastric emptying of liquids and slowing of gastric emptying of solids (P = 0.02). The postprandial duodenal motility index was greater with lactulose than with placebo (P = 0.031). This study demonstrates that LBT and GECS (without lactulose) are not equivalent measures of OCTT. The standard LBT accelerates OCTT and slows gastric emptying. Therefore, lactulose has a direct accelerating effect on small intestinal transit.

Adult↗
PubMed1997

Electrogastrography and gastric emptying scintigraphy are complementary for assessment of dyspepsia.

We have tried to correlate abnormalities in electrogastrography (EGG) and gastric emptying (GE) with symptom severity in patients with functional dyspepsia. Seventy-two patients with functional dyspepsia underwent EGG, GE, and symptom severity quantitation. EGGs were assessed for dominant frequency (DF), percentage of time of DF in the 2 to 4 cpm range, and postprandial-fasting DF power ratio. Solid-phase GE scintigraphy was assessed for 2-hour percentage retention. Symptoms of upper abdominal discomfort, early satiety, postprandial abdominal distension, nausea, vomiting, and anorexia were graded as none (0), mild (1), moderate (2), and severe (3); the sum represented a total symptom score. The EGG was abnormal in 11 of 22 (50%) patients with delayed GE compared with 11 of 50 (22%) with normal GE (p < 0.025). The total symptom scores were higher in patients with both delayed GE and abnormal EGG compared with patients with normal GE and EGG, normal GE and abnormal EGG, and delayed GE and normal EGG. We conclude that EGG abnormalities are more common in dyspeptic patients with delayed GE. Patients with both delayed GE and abnormal EGG have more severe symptoms. Our results suggest that EGG and GE complement each other in correlating symptoms to gastric dysmotility.

Adult↗
PubMed1997

Soft-tissue uptake of technetium-99m-MDP after prostate cryoablation.

Prominent soft-tissue uptake of 99mTc-methylene diphosphonate (MDP) within the prostate bed was found after cryoablation for prostate carcinoma. CT, MRI and sonographic studies demonstrated liquifactive necrosis of the prostate bed. The probable etiology for 99mTc-MDP uptake in this case is necrosis with subsequent neovascular hyperemia and microscopic calcium deposits. Three-phase scintigraphy with 99mTc-MDP appears to be useful for localizing the extent of soft tissue inflammation and necrosis.

Bone and Bones↗
PubMed1997

Delayed gastric emptying and decreased antral contractility in normal premenopausal women compared with men.

OBJECTIVES: The effects of gender on gastric emptying have not been fully elucidated. The aims of this study were to determine how gender affects gastric emptying and to see whether any of the observed differences in gastric emptying correlate with alterations in antral motility as measured by dynamic antral scintigraphy (DAS), cutaneous electrogastrography (EGG), and antroduodenal manometry (ADM). METHODS: Nine normal women [age 27.9 +/- 2.2 (mean +/- SEM) yr] in the first 10 days of the menstrual cycle and 13 normal men (age 27.5 +/- 1.7 yr) underwent simultaneous gastric emptying scintigraphy, DAS, EGG, and ADM. After an overnight fast and placement of an ADM catheter and EGG electrodes, a 60-min fasting recording was obtained, followed by ingestion of a 99m Tc-labeled solid meal. Measurements for all modalities were acquired every 10-15 min for 180 min. RESULTS: The gastric T1/2 was longer in women than in men [102 +/- 18 min vs. 71 +/- 4 (mean +/- SEM) min, p < 0.05]. A comparison of the gastric emptying pattern in women with that in men revealed no difference in proximal gastric emptying and lag phase, but in women the terminal slope of emptying was decreased compared with that in men (p < 0.05). The contractility measured in mid-antrum by DAS was significantly lower for women (p < 0.05). A decrease was also seen in the strength of contractions as measured by ADM. CONCLUSIONS: These data demonstrate that gastric emptying of solid food in normal young, premenopausal women is slower than in age-matched men, even during the first 10 days of the menstrual cycle. The findings suggest that the delay is due primarily to altered distal gastric motor function. This hypothesis was corroborated by finding decreased antral contractility as recorded by both dynamic antral scintigraphy and ADM. This study demonstrates the need to use appropriate control values to evaluate symptomatic female patients.

Adolescent↗
PubMed1996

Optimal evaluation of patients with nonobstructive esophageal dysphagia. Manometry, scintigraphy, or videoesophagography?

The aims of this study were to compare diagnostic accuracy, cost, and patient tolerance of videoesophagography and esophageal transit scintigraphy to esophageal manometry in the evaluation of nonobstructive esophageal dysphagia. Eighty-nine consecutive patients underwent videoesophagography, scintigraphy, and manometry. The sensitivities for diagnosing specific esophageal motility disorders, using esophageal manometry as the standard, were 75% and 68% for videoesophagography and scintigraphy, respectively, with positive predictive accuracies of 96% and 95% for achalasia, 100% and 67% for diffuse esophageal spasm, 100% and 75% for scleroderma, 50% and 67% for isolated LES dysfunction, 57% and 48% for nonspecific esophageal motility disorders, and 70% and 68% for normal esophageal motility. The cost for videoesophagography is less than that for either manometry or scintigraphy. Both videoesophagography and scintigraphy were better tolerated than manometry. It is concluded that videoesophagography and scintigraphy accurately diagnose primary esophageal motility disorders, achalasia, scleroderma, and diffuse esophageal spasm, but are less accurate in distinguishing nonspecific esophageal motility disorders from normal. When considering accuracy, cost, and patient acceptance, these findings suggest that videoesophagography is a useful initial diagnostic study for the evaluation of nonobstructive esophageal dysphagia.

Adult↗
PubMed1996

Gastrointestinal bleeding and cine-scintigraphy.

Two recent advances have significantly improved the ability of labeled red cell imaging to localize and to detect sites of active gastrointestinal bleeding. The first is the use of continuous dynamic imaging. The second is the commercial availability of an in vitro red cell labeling method that significantly improves image quality. The computer equipment required for dynamic imaging is available in most nuclear medicine laboratories. Because cinematic display of the dynamic images increases the accuracy and ease of interpretation it should be considered the method of choice for performing gastrointestinal bleeding studies. High-risk patients can be identified if very active bleeding is noted early. However, a study with negative results, after monitoring the patient over 1 to 2 hours, suggests that conservative medical management may be adequate. Therefore, with proper use scintigraphy can provide both diagnostic and prognostic information to aid in the management of patients with gastrointestinal bleeding.

Erythrocytes↗