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L A Forstrom

Publications and source records attributed to L A Forstrom.

At least 37 records · Page 2Linked to original sources
PubMed1995

111In-oxine-labelled granulocyte dosimetry in normal subjects.

The aim of this study was to determine organ uptake and dosimetry in human subjects using 111In granulocytes obtained by ficoll-hypaque purification. Anterior-posterior whole-body imaging was performed at 1, 3, 5, 24 and 48 h after injection of approximately 18.5 MBq (0.5 mCi) 111In granulocytes in 10 normal volunteers. Utilizing relative geometric mean analysis, the fraction of injected activity (FIA) was determined at each imaging time for the kidney, liver, lungs, bone marrow, spleen and whole-body remainder. Residence time was determined by integration of the bi-exponential fit of the FIA data over time. Curve fitting was performed with SAAM software (University of Washington). Red marrow uptake was calculated from activity in the L3-L4 vertebrae and iliac crests. Total body marrow uptake was extrapolated from these data using ICRP 23. Dose was determined with MIRDOSE 2 for the various organs. The liver had the highest organ uptake (40.3% at 48 h). The spleen, liver, red marrow, kidney and lung doses were 4.1, 1.6, 0.8, 0.5 and 0.4 mGy MBq-1, respectively. Urinary and stool excretion was negligible and blood clearance half-time was 6.9 h. Using current methods providing improved quantification of organ uptake and dosimetry, our results confirm the liver, spleen, bone marrow,lungs and kidneys to be the principal target organs of 111In granulocytes.

Bone Marrow↗
PubMed1995

Scintigraphy of the whole gut: clinical evaluation of transit disorders.

OBJECTIVE: To describe an initial clinical experience with a noninvasive scintigraphic technique for assessing gastrointestinal motility. DESIGN: We studied gastric, small bowel, and colonic transit in 109 unselected patients encountered between June and December 1992 at the Mayo Clinic. MATERIAL AND METHODS: The study patients were categorized on the basis of major complaint (constipation in 46, upper gastrointestinal symptoms in 45, and diarrhea in 18) and presence or absence of an underlying organic disease. Radioscintigraphy was used to analyze various regions of the gastrointestinal tract; scans were obtained at 2, 4, 6, and 24 hours after ingestion of a radiolabeled test meal. RESULTS: Overall, patients with a main complaint of constipation usually had slow or normal gastric, small bowel, and colonic transit, whereas those with diarrhea as the major symptom usually had normal or fast results of these studies. In the 65 patients with no underlying organic disease, inconsistent patterns of gastric emptying and small bowel and colonic transit were noted. CONCLUSION: Our results suggest that this 24-hour scintigraphic test may be clinically useful in screening for dysmotility syndromes in patients with nausea, vomiting, diarrhea, or constipation.

Adolescent↗
PubMed1995

A pilot study of splenic and whole body retention of autologous radiolabeled leukocytes in the assessment of severity in inflammatory colitis.

OBJECTIVE: To assess the splenic and whole body retention of radiolabeled autologous leukocytes over 24 or 48 h as measures of the severity of colitis. METHODS: Eleven patients with colitis underwent standardized clinical, endoscopic, histological, and 111In-labeled leukocyte scintigraphy. A logistic discriminant analysis was used to estimate weighting factors for morphological indices, serum albumen, and stool excretion of 111In over 24 h that predicted the clinical assessment of severity. Subsequently, Spearman rank correlation analysis estimated associations among reductions in spleen and whole body radioactivity and the derived indices of inflammation. RESULTS: The reduction in spleen counts over 24 h correlates significantly with morphological indices (rs = 0.83, p < 0.005) and with serum albumen and stool 111In (functional index, rs = 0.77, p < 0.01). Similarly, the reduction in whole body 111In over 48 h correlates significantly with the combined index (rs = 0.8) and with the morphological and functional index separately (rs = 0.72 and 0.79, respectively). CONCLUSION: This pilot study identified weighting factors for morphological and functional indices in assessing severity of colitis; reduction in whole body and splenic retention of radioactivity was sufficient for evaluation of severity of colitis without the need for stool collections.

Colitis, Ulcerative↗
PubMed1995

Evaluation of an inexpensive screening scintigraphic test of gastric emptying.

UNLABELLED: Our goal was to study the accuracy of a limited assessment relative to the traditional and obtain a more detailed approach to measure gastric emptying. METHODS: We prospectively evaluated 35 patients referred to our laboratory with suspected fast or slow gastric emptying. Transit was measured radioscintigraphically after ingestion of an egg meal containing 99mTc-Amberlite pellets. Gastric emptying was analyzed by power exponential analysis. Diagnostic accuracy of simpler indices (gastric residual at 2 and 4 hr) was determined by comparing the categorization of patients as normal or abnormal relative to previously published normal data from our laboratory. RESULTS: Gastric residual at 2 hr showed greater diagnostic accuracy for accelerated gastric emptying with 90% sensitivity at 90% specificity. Gastric residual at 4 hr was less accurate for accelerated emptying, but was more accurate at detecting delayed gastric emptying with 100% sensitivity at 70% specificity. In contrast, sensitivity and specificity of gastric residual at 2 hr for slow emptying were low (100% sensitivity with 20% specificity) emphasizing the importance of obtaining a scan later than 2 hr for detecting delayed gastric emptying. CONCLUSION: Selective scans taken at 2 and 4 hr provide an excellent screening test for detecting fast or slow gastric emptying; the accuracy of 2-hr data is optimal for accelerated emptying and that of the 4-hr data greater for delayed emptying. This strategy provides a simple, less expensive way to evaluate gastric emptying in clinical practice with acceptable sensitivity and specificity as an initial test for patients with clinically suspected gastric stasis or dumping syndromes.

Anion Exchange Resins↗
PubMed1994

The radiation dosimetry and normal value study of 99mTc-HMPAO-labeled leukocytes.

RATIONALE AND OBJECTIVES: Indium-111 (111In)-labeled leukocyte scanning has been used frequently in patients suspected of having infections. Recently, technetium-99m hexamethylpropylene amine oxime (99mTc-HMPAO) has been used to label leukocytes. This study was undertaken to determine the distribution and dosimetry of 99mTc-HMPAO leukocytes in healthy subjects. METHODS: Five healthy volunteers had leukocytes labeled with 99mTc-HMPAO. After injection of the labeled leukocytes, whole body images and blood and urine samples were obtained at multiple time points. RESULTS: Visual interpretation of the images demonstrated significant bowel activity as early as 2 hours and increasing with time such that one the 8- and 24-hour images, the amount of bowel activity would preclude using 99mTc-HMPAO leukocyte scanning for abdominal processes. The dosimetry for this study is similar to that of other studies and is in an acceptable diagnostic range. CONCLUSIONS: 99mTc-HMPAO leukocyte studies are an acceptable alternative to 111In-labeled leukocyte studies in terms of dosimetry. Use of such studies in the abdomen should be limited to early images, usually before 2 hours, to avoid confusion with the normal route of excretion in the bowel.

Female↗
PubMed1993

Scintigraphic findings of renal oncocytoma.

Tc-99m DTPA scintigraphy of most renal tumors characteristically discloses a vascular mass, without retention of activity on serial images. Two cases, encountered during hypertensive work-up, are presented with vascular renal masses and persistent DTPA uptake. Oncocytoma was confirmed pathologically in both cases. The authors conclude that renal oncocytomas have a relatively distinctive scintigraphic appearance, which may permit accurate preoperative diagnosis.

Adenoma, Oxyphilic↗
PubMed1993

Gastric axial forces in experimentally delayed and accelerated gastric emptying.

The aim of this study was to assess the relationship between altered axial forces and gastric emptying of solids by experimentally inhibiting or stimulating gastric axial forces by intraduodenal lipid or intravenous erythromycin, respectively. In 15 healthy volunteers, we simultaneously measured gastric emptying of solids by scintigraphy, gastroduodenal motility by manometry, and forces along the longitudinal axis of the distal stomach by an axial force transducer. When 25% of the radiolabel had emptied from the stomach, subjects (n = 5 in each group) received normal saline (controls), intraduodenal lipid, or intravenous erythromycin. The test period consisted of the infusion period (10 min) and the subsequent 30 min. Lipid significantly reduced and erythromycin increased axial forces compared with control (lipid: median 0.6 N [0-1.4 interquartile range (IQR)]; erythromycin: median 18.2 N (16.5-20.5 IQR); control: median 4.7 N (3.9-5.2 IQR); P < 0.01). Similarly, antral phasic pressure activities were different relative to control. Gastric axial forces correlated significantly with gastric emptying (Spearman rank correlation = 0.86; P < 0.01). These data are consistent with the hypothesis that axial forces affect gastric emptying of solids and suggest that measurement of axial forces provides an assessment of overall gastric propulsion during the emptying of solids.

Adult↗
PubMed1990

In vivo viability and functional integrity of filtered platelets.

The in vivo viability and functional integrity of filtered platelets were compared with those of nonfiltered platelets in a controlled study. On two occasions, after template bleeding time, 14 healthy volunteers underwent plateletpheresis and received 600 mg of aspirin. Autologous 111In-labeled platelets were transfused without further manipulation (control) on one occasion and after filtration on a second occasion. The filter was primed and flushed with a buffered 12.6-percent solution of ACD-A in 0.9-percent normal saline (pH 6.5). After transfusion, the bleeding time was measured at 1, 4, and 24 hours and platelet survival at 10 minutes; 1, 4, and 24 hours; and daily for 6 days. The decrease in the bleeding time was not significantly different from that after transfusion of nonfiltered platelets (p greater than 0.2). Filtering of platelets did not affect 1-hour in vivo recovery (filtered, 69.5%; nonfiltered, 66%: p = 0.56) or the platelet survival (filtered platelet t1/2 = 83.0 hours, nonfiltered platelet t1/2 = 82.9 hours: p = 0.96). It can be concluded that filtration does not adversely affect in vivo recovery, survival, or functional integrity of platelets.

Bleeding Time↗
PubMed1989

Effects of biliary obstruction on hepatic clearance of bacteria.

High surgical mortality in patients with obstructive jaundice and sepsis have been attributed to reticuloendothelial system (RES) depression. The purpose of this study was to clarify the effects of mechanical biliary obstruction on RES clearance of pathogenic bacteria by comparing the phagocytic index (K) with the directly measured hepatic uptake of indium 111-labeled bacteria injected into the portal vein of normal dogs and dogs with partial (PBO) or complete biliary obstruction (CBO). No significant difference was observed between the K in normal dogs (0.19 +/- 0.08; n = 6) and that in dogs with PBO (0.24 +/- 0.06; n = 5) or CBO (0.21 +/- 0.03; n = 4). There was no significant difference in uptake of radiolabel by the liver among the three groups of dogs. In our model, biliary obstruction had no effect on hepatic RES function and may not represent a significant determinant of mortality in patients with obstructive jaundice.

Alkaline Phosphatase↗
PubMed1988

Labeled polymorphonuclear leukocytes: a comparison of methodology.

Polymorphonuclear neutrophilic granulocytes were separated from anti-coagulated whole blood using three techniques. The methods employed included volex sedimentation (VS), volex sedimentation with hypotonic lysis (VSHL), and Ficoll-Hypaque gradient separation (FH). The cells were labeled with 111In-oxine and 111In-tropolone. Studies were done with both blood from normal human volunteers and with canine blood. From the cell counts and differential, the harvested granulocytes, platelets, and red blood cells per milliliter of whole blood were calculated. Using the granulocyte chemotactic response to E. coli in agarose plates, the ratio of chemotactic migration to random migration (c.m./r.m.) was determined. Survival time for 111In labeled granulocytes were also determined in a canine model. The studies demonstrated that all procedures yielded 100% viability by the Trypan blue exclusion test. Chemotactic migration and leukocyte survival times were similar amongst all techniques. With the VSHL technique, there were significantly fewer red blood cells and platelets in the final preparation approaching the results of FH separation. The results suggest that for a relatively pure granulocyte preparation VSHL is an acceptable alternative to FH.

Animals↗
PubMed1988

Indium-111 labeled purified granulocytes in the diagnosis of synthetic vascular graft infection.

Indium-111 labeled leukocytes have been shown to be useful in the diagnosis of synthetic vascular graft infection. To minimize the potential effects of labeled red blood cells and platelets on image interpretation, the authors prepared purified autologous granulocytes (PG) from 84 ml of blood using Volex enhanced gravity sedimentation and Ficoll-Hypaque double density centrifugation. The labeling efficiency of PG with In-111 tropolone was 90 +/- 9% (mean +/- SD). Imaging was performed 18-24 hours following injection of approximately 445 microcuries of In-111 PG in 26 patients with suspected infection of vascular grafts that had been implanted 12 days to 12 years prior to the study. In ten patients with proven graft infection, seven had positive In-111 PG scans. Ten of 11 patients without infection had negative scans. In five patients with clinically equivocal findings, scan results were positive in one, negative in one, and equivocal in three. A false-positive scan occurred in a patient with an uninfected inflammatory pseudoaneurysm of an aortic graft. These results confirm an earlier report that In-111 PG imaging is a useful technique in the diagnosis of synthetic vascular graft infection.

Aged↗
PubMed1988

Indium-111 platelet kinetics in patients with diabetes mellitus.

We performed in vitro aggregation and indium-111 labeled platelet kinetic and biodistribution studies in seven patients with diabetes mellitus and in five control subjects. All subjects were male. All diabetic patients were poorly controlled at the time of study with blood glucose greater than 140 mg % and hemoglobin A1c greater than 10%. In vivo kinetic and biodistribution studies were performed following reinjection of autologous platelets labeled with indium-111 oxine in a dose of approximately 50 microCi (42-67 microCi). Images obtained at 4 and 24 h were computer-analyzed to determine splenic and hepatic uptake, and platelet survival times were calculated using four mathematical models. Unexpectedly, diabetic patients with fewer vascular complications tended to have shorter platelet survival times than patients with advanced vascular disease. However, no significant differences were observed between diabetic and control groups for any of the parameters of platelet function evaluated.

Blood Platelets↗
PubMed1988

Thrombocytopenia after liver transplantation.

Thrombocytopenia occurs in postoperative liver transplant patients, with platelet counts reaching a nadir on the third postoperative day. Significant bleeding episodes are not uncommon during the first five days postoperatively when platelet counts are low. This thrombocytopenia may be the result of platelet sequestration in the newly grafted liver. The sequestration phenomenon does not appear to be on the basis of antiplatelet antibody activity. Further work defining the time course of this organ sequestration and evaluating the possible release of previously sequestered platelets back into the circulation need to be done. Also, it may be productive to study medications known to inhibit platelet activation (ie, cyclooxygenase inhibitors, prostacyclin, and calcium channel blockers) with the intent of interrupting platelet adhesiveness-sequestration at the time of recirculation of the newly grafted liver.

Hemorrhage↗
PubMed1985

Relation between in vivo abscess localization and in vitro migration and adherence of neutrophils.

Rabbit peripheral blood and glycogen-stimulated peritoneal neutrophils were labeled with [111In]indium oxine and transfused intravenously into recipient rabbits with experimental abdominal abscesses due to Staphylococcus aureus. Peritoneal neutrophils harvested 4 hr after glycogen infusion localized within the abscesses to a greater extent than did peripheral blood neutrophils (P less than .002). In an in vitro chemotaxis under-agarose assay, peripheral blood neutrophils had greater random migration (P less than .002) and directed migration (P less than .01) than did peritoneal cells. In an in vitro glass slide adherence assay, peritoneal neutrophils were more adherent than were blood neutrophils (P less than .05). The discrepancy between in vivo and in vitro findings may be due to the increased adherence of peritoneal neutrophils. Glycogen-stimulated peritoneal neutrophils have been exposed in vivo to C5a, which is known to decrease migration and increase adherence in vitro of polymorphonuclear neutrophils; consequently, in vivo exposure of neutrophils to C5a may mean in vitro migration data may be misleading in predicting results in vivo.

Abscess↗
PubMed1983

Decrease in thallium-201 image defect size after permanent coronary occlusion.

In the 24 hours after coronary occlusion, some defects on thallium-201 images decrease in size. This study examined the mechanism of the decrease in defect size in dogs with experimental coronary occlusion. The left anterior descending coronary artery was permanently occluded in chronically instrumented awake dogs. Myocardial blood flow was measured with radioactive microspheres immediately before occlusion, 30 minutes, and 24 hours after occlusion. Thallium-201 was injected and imaging was performed 2 to 6 days before occlusion, 30 minutes, and 24 hours after occlusion. Two dogs, in which less than 1% of the left ventricle was infarcted, had no defects on the 30-minute postocclusion images. In four dogs the thallium-201 images did not change appreciably over 24 hours (group 1), while in three dogs the image defect size decreased (group 2). In groups 1 and 2 respectively the percent increase in blood flow to the hypoperfused area was: subendocardium 9 +/- 7% vs 31 +/- 15%; subepicardium 26 +/- 6% vs 47 +/- 2% (p less than 0.05). Therefore a decrease in the size of thallium-201 image defects occurred if a sufficient increase in collateral flow to the hypoperfused area took place in the first 24 hours after coronary occlusion. The defects appeared to decrease in size even in the absence of a detectable change in the lateral borders of the hypoperfused area.

Animals↗