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Biomedical subjects

L S Malmud

Publications and source records attributed to L S Malmud.

At least 73 records · Page 4Linked to original sources

Calculation of net renal uptake curves without use of a blood pool agent.

The usual method of generating net Hippuran renal uptake curves involves the administration of a blood pool agent. Two techniques are presented which permit the determination of net renal uptake curves from data intrinsic to the Hippuran study. This reduced the complexity of the procedure, as well as reducing its cost and decreasing the radiation exposure. The new procedures were tested in 9 patients and showed excellent correlation with the blood pool agent technique.

Humans↗

Myocardial infarct imaging with 99mTc-pyrophosphate and 99mTc-methylene diphosphonate: lack of correlation.

A prospective study of eight patients with recent transmural myocardial infarction was performed using 99mTc-Sn-pyrophosphate and 99mTc-Sn-methylene diphosphonate in each patient. All pyrophosphate scans were strongly positive whereas the diphosphonate scan was strongly positive in only one case. We conclude that 99mTc-Sn-pyrophosphate is preferable to 99mTc-Sn-methylene diphosphonate for myocardial imaging.

Diphosphates↗

The mode of action alginic acid compound in the reduction of gastroesophageal reflux.

This study was designed to evaluate quantitatively the mode of action of alginic acid compound (AAC) in the treatment of patients with symptomatic gastroesophageal reflux. Gastroesophageal scintigraphy using an orall administered Tc-99m sulfur colloid solution was used to demonstrate that AAC decreased significantly the gastroesophageal reflux index from (9.9 +/- 1.3) % to (6.5 +/- 0.8) % (p less than 0.05). No alteration of lower esophageal sphincter pressure was observed. After ACC was suitably labeled with Sr-87m, a dual-nuclide scintigraphic technique was used to show that most (greater than 75%) of the AAC was located in the upper half of the stomach in both normal subjects and patients with gastroesophageal reflux. In those subjects in whom reflux did occur after treatment with AAC, the Sr-87m-AAC refluxed into the esophagus preferentially compared with the liquid containing Tc-99m sulfur colloid. These findings suggest that AAC dimishes gastroesophageal reflux by means of its foaming, floating, and viscous properties.

Adult↗

Esophageal scintigraphy to quantitate esophageal transit (quantitation of esophageal transit).

None of the tests employed currently to investigate esophageal transit is quantitative. The purpose of this study was to evaluate normal subjects and patients with a variety of esophageal disorders using a scintigraphic technique to quantitate esophageal transit. After oral administration of a bolus of water labeled with 99mTc-sulfur colloid, isotopic count rates were measured over the esophagus employing a gamma-camera on line to a digital computer. Esophageal transit was expressed as the percent emptying for each of the first 15-sec after the initial swallow and for 15-sec intervals after serial swallows. Sixty-two subjects were studied, including: normal volunteers; patients with motor disorders of the esophagus such as achalasia, diffuse esophageal spasm, and scleroderma; and patients with symptomatic gastroesophageal reflux both with and without esophageal motor dysfunction on manometic testing. Esophageal transit was decreased significantly after single and multiple swallows in patients with motor disorders of the esophagus. In addition, esophageal transit was abnormal in patients with reflux disease accompanied by abnormal motor function. In contrast, esophageal transit was normal after a single swallow, but incomplete after serial swallows in patients with reflux associated with normal esophageal motor function on manometry. We conclude that esophageal scintigraphy may be used to evaluate esophageal transit.

Adult↗

Enterogastric reflux in normal subjects and patients with Bilroth II gastroenterostomy. Measurement of enterogastric reflux.

Initially, scintigraphy was established as a valid method for detecting and quantitating enterogastric reflux. A new, tubeless technique for the measurement of enterogastric reflux was developed. 99mTc bound to [(2,6 dimethylphenylcarbamoylmethyl) iminodiacetic acid] (5 mCi) was administered intravenously to visualize the liver and biliary tract. One hour later, a standard liquid meal labeled with 111In bound to diethylene-triamine penta-acetic acid (250 microCi) was given. The 99mTc and 111In activities were recorded simultaneously for 1-min periods at 15-min intervals for 2 hr over liver, gallbladder, and gastric areas of interest. Enterogastric reflux indices were determined. Ten normal subjects and 13 patients with vagotomy, hemigastrectomy, and Bilroth II gastrojejunostomy were evaluated. The enterogastric reflux index in asymptomatic postsurgical patients was increased significantly to 24.6 +/- 4.7 compared with 8.2 +/- 6.0 (P less than 0.01) in normal subjects. In postsurgical patients with the syndrome of alkaline gastritis, the enterogastric reflux index was increased significantly to 86.3 +/- 7.1 (P less than 0.01) compared with asymptomatic postsurgical patients.

Esophagitis, Peptic↗

Antireflux surgery for symptomatic gastroesophageal reflux: mechanism of action.

To determine the effects of Nissen fundoplication upon the symptoms of reflux and the diagnostic tests employed to evaluate reflux and to examine the relationship between gastroesophageal reflux and lower esophageal sphincter pressure before and after fundoplication, 10 patients with symptomatic reflux were studied before and after operation. Clinical evaluation, barium esophagography, endoscopy with mucosal biopsy, esophageal manometry, acid-perfusion and acid-reflux testing, and gastroesophageal scintiscaning were performed on each patient before and after surgery. Following fundoplication, marked symptomatic, radiographic, endoscopic, and histologic improvement was observed. Serial acid-reflux tests at increasing gastroesophageal pressure gradients returned to normal after surgery. Lower-esophageal-sphincter (LES) pressure increased from 8.2 +/- 1.3 to 12.0 +/- 1.5 mm Hg (P less than 0.01). In addition, surgery resulted in a significant decrease in the gastroesophageal reflux index from 17.4 +/- 2.4 to 2.7 +/- 1.1% (P less than 0.001). Surprisingly, the pre- and postoperative resting LES pressures did not correlate significantly with corresponding gastroesophageal reflux indices for individual patients. We conclude that increased LES pressure alone does not explain adequately the functional and clinical improvement which follows fundoplication.

Adult↗

The lower esophageal sphincter as a barrier to gastroesophageal reflux.

UNLABELLED: To correlate lower esophageal (LES) pressure and gastroesophageal (GE) reflux, esophageal manometry and GE scintiscanning have been used to study 40 consecutive patients. Serial scintiscanning was performed as the GE pressure gradient was increased in increments. Reflux was calculated from the ratio of esophageal to gastric radioactivity. The relationship between GE reflux and LES pressure was inverse (r = 0.60, P less than 0.005). Two subgroups of 10 patients were studied further. After atropine, LES pressure decreased from 11.2 +/- 1.1 to 5.3 +/- 0.9 mm Hg (P less than 0.01) at 20 min. The GE reflux index increased from 8.3 +/- 2.1 to 13.4 +/- 2.2% (P less than .05). After bethanechol, LES pressure increased from 8.9 +/- 0.8 to 18.5 +/- 1.0 mm Hg (P less than 0.001) at 30 min. GE reflux decreased from 11.9 +/- 2.4 to 5.8 +/- 1.7% (P less than 0.01). CONCLUSIONS: first, GE reflux correlated with basal LES pressure by an inverse relationship; second, atropine decreased LES pressure and increased reflux; third, bethanechol increased LES pressure and decreased reflux. These data suggest that LES pressure is an important determinant of GE competence.

Atropine↗

Gastrointestinal plasma protein loss during ethanol ingestion.

Plasma and "equivalent" albumin loss in the feces were quantitated before and during ingestion of 40% ethanol using 51Cr-labeled albumin. Five subjects were studied in each classification of normal gastric mucosa, superficial gastritis, and chronic atrophic gastritis. During the control period, plasma albumin loss was minimal and similar in all three groups. Exposure to ethanol resulted in a greater output of plasma albumin in the feces of all subjects. This loss was statistically significant in subjects with superficial gastritis (P less that 0.01) and chronic atrophic gastritis (P less than 0.005). Two subjects from each group underwent gastric clearance studies of 51Cr-labeled albumin. Increased gastric clearance of plasma was observed in all 6 subjects during ethanol ingestion; the increase was highly significant in subjects with atrophic gastritis (P less than 0.001). We conclude that ethanol ingestion can cause increased loss of plasma protein in the feces, which may be of clinical significance in subjects with atrophic gastritis.

Adult↗

Gastroesophageal (GE) scintiscanning to detect and quantitate GE reflux.

To evaluate the gastroesophageal (GE) scintiscan, a technique which detects and quantitates GE reflux, 30 patients with heartburn and a positive acid-reflux test and 20 normal control subjects were studied. Conventional diagnostic tests including barium esophagography, fluoroscopy, esophagogastroscopy, esophageal biopsy, acid perfusion testing, and esophageal manometry were performed on each patient with GE reflux. None of these techniques was sufficiently sensitive in detecting GE reflux. In contrast, GE reflux was visualized by scintiscanning in 27 out of 30 (90%) of patients. The GE reflux index was significantly greater in reflux patients, 11.7 +/- 1.8%, compared to controls 2.7 +/- 0.3%. These studies suggest that GE scintiscanning can detect GE reflux accurately, rapidly, noninvasively, and with greater sensitivity than other diagnostic techniques. In addition, it can be employed to quantitate GE reflux.

Adult↗

Preoperative bone scans. Use in women with early breast cancer.

Strontium nitrate Sr 87m bone scans were made preoperatively in a group of women with suspected breast cancer, 35 of whom subsequently underwent radical mastectomy. In 3 of the 35 (9%), the scans were abnormal despite the absence of clinical or roentgenographic evidence of metastatic disease. All three patients has extensive axillary lymph node involvement by tumor, and went on to have additional bone metastases, from which one died. Roentgenograms failed to detect the metastases in all three. Occult bone metastases account in part for the failure of radical mastectomy to cure some patients with breast cancer. It is recommended that all candidates for radical mastectomy have a preoperative bone scan.

Adult↗

Bone scanning: principles, technique and interpretation.

Bone scanning is most useful in the detection of bone metastases. The recent introduction of new radiopharmaceuticals and instrumentation has reduced the time needed to perform the study and its relative cost, while increasing the usefulness of the study in detecting roentgenographically occult diseases. Metastatic disease is used as the pathophysiologic model for understanding the principles of bone scanning. When a tumor invades bone, in addition to causing bone destruction, it also causes reactive bone formation or repair. It is here that radioisotopes are of considerable value, since some radionuclides are incorporated into the hydroxyapatite crystals of reactive bone. Bone repair is described as occurring in three phases. In Phase I, the roentgenogram shows no change in bone density, but the scan is abnormal. In Phase II, both scintigraphic and roentgenographic abnormalities increase, and in Phase III, when the osteoid has calcified completely, the roentgenogram shows radiodensities and the scan appears almost normal. Fewer than 5 per cent of patients have a normal scan in the presence of an abnormal roentgenogram. Presently, most bone scans are performed with phosphate compounds labeled with -99m-Tc. In the past, 85-Sr, 87M-Sr, and 18-F were more broadly used. Scanning may be performed on either a rectilinear scanner or a scintophoto (gamma) camera. Areas which are abnormal on bone scan should be interpreted with current roentgenograms in the light of clinical findings.

Autopsy↗