sodium-pertechnetate-tc-99m and Inflammation

An amount of 1.0 mg human immunoglobulin G (hIgG) treated with ascorbic acid at a molar ratio of 1:5000 for 16 h at 4-7 degrees C was mixed with 250 micrograms GHA and 5 micrograms stannous chloride dihydrate in normal saline. Radiolabelling of hIgG (> 98%) was achieved instantly when mixed with 99Tcm-pertechnetate. The preparation was sufficiently stable in serum at 37 degrees C. The competitive binding assay and gel electrophoresis of the native and reduced hIgG did not show any measurable loss in immunoreactivity and intactness due to its reduction. There was no significant decrease in the radiolabel of labelled hIgG when incubated with diethylenetriaminepentaacetate (DTPA) (50-fold), in contrast with about 9% loss of the radiolabel by treating it with a similar concentration of cysteine. Blood clearance of labelled hIgG in rabbits was biphasic with about 78 min and 8 h as T1/2 of the fast and slow phases. Biodistribution of the radiotracer in mice at 4 h showed its uptake by liver (10.2%), kidneys (5.39%), intestines (7.33%) and muscles (3.9%), which altered to 5.63, 3.20, 4.03 and 6.73%, respectively, at 24 h. The radiotracer was excreted through both renal and hepatobiliary routes. High accumulation of the radiolabelled hIgG in inflammatory lesions of the patients confirmed the clinical usefulness of the method developed.

Topics: Animals; Cysteine; Drug Stability; Humans; Immunoglobulin G; Indicators and Reagents; Inflammation; Intestinal Mucosa; Intestines; Isotope Labeling; Kidney; Liver; Metabolic Clearance Rate; Mice; Muscles; Organotechnetium Compounds; Pentetic Acid; Rabbits; Sodium Pertechnetate Tc 99m; Tin Compounds; Tissue Distribution; Tomography, Emission-Computed, Single-Photon

To evaluate clinical efficacy of a dual-time acquisition protocol, which included 4 and 20/24-h imaging with antigranulocyte antibody scintigraphy (LeukoScan) combined with semiquantitative analysis in the diagnosis of infection in painful hip prosthesis.. Sixty-seven consecutive patients with hip prosthesis were enrolled in this research project: 35 females, 32 males, mean age of 56.3 years. All patients had clinical and biochemical suspicious of infection. Each prosthesis had been implanted 3 months to 12 years before enrollment in this study. Twenty-four patients were on antibiotic therapy at the time of scintigraphy. Seven patients had bilateral hip prosthesis, one painful and the other painless: the seven painless prostheses were considered controls. LeukoScan examination was performed both at early (4 h) and delayed (20/24 h) times. The scintigraphic data were assessed both by visual and semiquantitative methods by three experienced nuclear medicine physicians blinded to clinical, laboratory and radiographic results. The uptake was graded visually by a 4-point scale: intense=3, moderate=2, mild=1 and absent=0. The semiquantitative analysis was obtained by a region of interest (ROI) analysis used in the anterior views to measure the ratio between the mean radioactivity in the prosthesis and the background radioactivity in the early and delayed images. An increase in the intensity of uptake of at least one scale-step at visual analysis and 20% at semiquantitative ROI analysis at the dual-time (early vs. delayed) LeukoScan was considered consistent with infection, whereas a stable or decreasing pattern was judged a negative result. Three-phase 99mTc-hydroxymethane diphosphonate bone scan was also performed routinely. Final diagnosis was determined at surgery and/or long-term clinical and imaging follow-up.. At visual analysis, sensitivity for both early and delayed imaging was 94%, whereas specificity was 71% for early imaging and 83% for early and delayed imaging approach. At semiquantitative ROI analysis, sensitivity remained 94%, whereas specificity rose slightly to 73% for early imaging and to 90% for early and delayed imaging combined. Of note, four false-positive early scans were diagnosed correctly as negative on delayed imaging showing a decreasing pattern in uptake intensity. Sensitivity and specificity were similar whether patients were on or off antibiotic therapy.. Our data show that early imaging LeukoScan is highly sensitive in evaluating septic prosthesis, but it is not optimally specific. Although the dual-time LeukoScan is capable of significantly increasing specificity for detecting infection. The semiquantitative ROI analysis further increased the specificity. Concomitant antibiotic treatment did not seem to influence the diagnostic efficacy of LeukoScan scintigraphy in detecting infected hip prosthesis.

Topics: Aged; Animals; Arthroplasty, Replacement, Knee; Bacterial Infections; Epitopes; Female; Granulocytes; Hip Prosthesis; Humans; Immunoglobulin Fab Fragments; Inflammation; Knee Joint; Male; Mice; Middle Aged; Prospective Studies; Pseudomonas aeruginosa; Radionuclide Imaging; Radiopharmaceuticals; Sodium Pertechnetate Tc 99m; Staphylococcus aureus

Chemotactic peptides, such as Monocyte Chemotactic Protein 1 (MCP-1), play a key role in transendothelial migration of mononuclear cells during the development and progression of atherosclerotic disease. Because atherosclerotic plaques that are precursors of acute coronary events harbor abundant macrophage infiltration, we hypothesized that the detection of a high concentration of MCP-1 receptors on inflammatory cells should noninvasively identify vulnerable plaques.. Atherosclerotic lesions were induced by balloon deendothelialization of the abdominal aorta, which was followed by a 0.5% cholesterol diet for 16 wk in 7 New Zealand White rabbits; 5 unmanipulated rabbits, fed normal chow for 16 wk, were used as controls. Radionuclide imaging was performed immediately after intravenous (99m)Tc-labeled MCP-1 administration and 3 h later. At the end of imaging session, aortas were explanted and submitted for estimation of quantitative MCP-1 uptake (in percentage injected dose per gram, %ID/g) and pathologic characterization.. Atherosclerotic lesions were clearly visible in all hyperlipidemic animal gamma-imaging. No tracer uptake was seen in the control rabbits. The mean quantitative MCP-1 uptake in atherosclerotic lesions was 4-fold higher than that of the aortic specimens from the control rabbits (0.065 +/- 0.005 vs. 0.016 +/- 0.006; P < 0.0001). Histology confirmed a strong correlation between MCP-1 uptake and the number of macrophages in American Heart Association type II-IV lesions (r = 0.87, P < 0.0001).. Noninvasive radionuclide imaging of inflammation is feasible by MCP-1 in experimentally induced atherosclerosis. It is proposed that detection of the extent of inflammation in advanced atherosclerotic plaques may allow identification of unstable plaques.

Topics: Animals; Atherosclerosis; Chemokine CCL2; Diet, Atherogenic; Humans; Inflammation; Macrophages; Rabbits; Radionuclide Imaging; Radiopharmaceuticals; Recombinant Proteins; Sodium Pertechnetate Tc 99m

Tc-Human immunoglobulin G ( Tc-HIG) is a well-known radiopharmaceutical for the evaluation of inflammatory lesions. Recently, it has been demonstrated as a new agent for the visualization of the lymphatic system by our group. Our aim was to investigate the feasibility of detection of inflammatory lymph nodes by Tc-HIG lymphoscintigraphy. Ten adult New Zealand rabbits were used as group A. In a baseline study, 37 MBq Tc-HIG (0.1 ml) was injected into both hind legs of the rabbits, and sequential posterior gamma imaging with the rabbits lying prone was performed at 5, 15, 30, 60, 90 and 120 min using a single-headed gamma camera (Toshiba GCA G01 E). One week later, microorganisms ( ) were injected in a volume of 0.1 ml intradermally into the web space between the second and third toes in the bilateral hind legs of each rabbit in order to obtain inflammation in the popliteal lymph nodes. After 4 days, 37 MBq Tc-HIG (0.1 ml) was injected into the hind legs of the rabbits bilaterally, and sequential posterior gamma imaging was performed as described above (second study). Another group of 10 adult New Zealand rabbits (group B) was injected with the same microorganisms in the right hind legs only. After 4 days, scintigraphic imaging was carried out in the same way as described above (third study). Regions of interest were drawn over the injection sites and popliteal lymph nodes on each image for semiquantitative analysis. Count rates for each were calculated and a decay correction was applied. Time-activity curves were generated to show the percentage retention of radioactivity in each region. After the scintigraphic study, some of the group B rabbits were killed by intravenous injection of pentobarbitone (100-150 mg.kg, and both left and right lymph nodes were removed for microscopic examination. On the scintigrams, lymphatic channels and popliteal lymph nodes were visualized within 15 min. In the second study, bilateral popliteal lymph nodes were visualized more clearly than in the baseline study. The right popliteal lymph nodes of the rabbits were more clearly visualized in the third study. Semiquantitative analysis showed a higher percentage uptake of radioactivity in the right compared to the left popliteal lymph nodes in group B rabbits. Microscopic examination of the tissue sections demonstrated inflammation in the right lymph nodes of group B rabbits. In this preliminary study, it was found that Tc-HIG is a new promising agent for the demonstration and e

Topics: Animals; Chromatography, Thin Layer; Humans; Immunoglobulin G; Inflammation; Lymph Nodes; Lymphatic Diseases; Organotechnetium Compounds; Rabbits; Radionuclide Imaging; Radiopharmaceuticals; Sodium Pertechnetate Tc 99m; Staphylococcal Infections

Microvascular albumin exchange and sequestration of inflammatory cells into the lungs of anesthetized guinea pigs immunized to ovalbumin were evaluated using radioactive tracers. Increased exchange of radiolabeled (*) albumin from airways to blood was noted in immunized and boosted animals under basal conditions. After the intratracheal injection of 300 micrograms of ovalbumin, an additional increase in exchange through epithelium occurred, since the rate of appearance of *albumin in blood was enhanced compared with control (140 +/- 30 vs. 54 +/- 20% in 1 h). The augmentation of lung content in extravascular *albumin compared with control (16.2 +/- 4.0 vs. 5.9 +/- 1.6%) indicates that transendothelial exchange was also facilitated. Concomitment with the sequestration of *platelets into the lungs of antigen-challenged sensitized animals (59.2 +/- 20% in 1 h), leukocytes (> 60% polymorphonuclear neutrophils) did not marginate. Histamine released during antigenic shock might promote leukocyte demargination from the vascular bed through its vasomotor effect and/or by inhibiting leukocyte activation and consequently may counteract the effects of other inflammatory mediators acting to sequester neutrophils. In confirmation, perfusion of histamine to the immunized animals induced demargination of lung leukocytes. Histamine antagonists prevented the increased exchange of *albumin through the epithelial and endothelial barriers and uncovered *leukocyte sequestration (100.7 +/- 28.9% in 1 h) in the lungs of antigen-challenged animals. Histamine antagonists may favor antigen-induced leukocyte sequestration in the lungs by preventing the effects of endogenous histamine on capillary recruitment and blood flow.

Topics: Animals; Antigens; Blood Platelets; Blood Volume; Bronchoalveolar Lavage Fluid; Erythrocytes; Guinea Pigs; Histamine; Histamine H1 Antagonists; Histamine H2 Antagonists; Inflammation; Leukocytes; Lung; Ovalbumin; Sodium Pertechnetate Tc 99m

Little information is available on the role of inflammation and small vessel alteration in the development and healing of peptic ulcers. We studied the spontaneous healing of experimental ulcers in the rat stomach with a novel radio-isotope technique for the monitoring of capillary damage in ulcer-related inflammation. Following ulcer induction, healing was assessed on days 1, 7 and 15 by macroscopical and histological determinations of ulcer size and lesion area, parietal cell counts in the ulcer margin and nuclear imaging of the lesion area using Nanocoll, a 99mTc-labelled colloid. The ulcers were re-epithelized after 15 days. However, Nonocoll activity was still significantly enhanced in the ulcer area, and regression of the microscopically visible lesion area, which, from day 1 on, occupied a zone considerably larger than the ulcer itself, was delayed and still incomplete at the end of the study. Compared to the intact mucosa, parietal cells were reduced in the scar tissue up to 15 days (24-40%). However, despite macroscopical and histological re-epithelization, small vessel leakage and substantial tissue alteration persisted in the ulcer scar.

Topics: Animals; Capillary Permeability; Colloids; Female; Inflammation; Radionuclide Imaging; Rats; Rats, Inbred Strains; Sodium Pertechnetate Tc 99m; Stomach Ulcer; Wound Healing

Anaesthetised guinea-pigs received tracer macromolecules 70-340 kDa intravenously and their erythrocytes were labelled in vivo with 99mTc. Superfusion of tracheal mucosa (via oral catheter) with control solutions and inflammatory agents, was followed by sampling of tracheal surface liquids and tracheal tissue. Under baseline conditions no 125I-fibrinogen (340 kDa) and minimal amounts of erythrocytes, 131I-albumin (70 kDa), and FITC-D (150 kDa) were found in tracheal lavage fluids. Undisturbed baseline conditions with negligible leakage of plasma into airway tissue and lumen were thus obtained with the present provocation and sampling techniques. Superfusion during 2 min with bradykinin 2-10 nmol, histamine 2-8 nmol, capsaicin 0.1-0.4 nmol, PAF 4-8 nmol, ovalbumin 3-6 pmol (in sensitised animals) produced, within 1-10 min, a significant and dose-dependent accumulation of plasma in tracheal tissue and lavage fluids. PAF also induced a late phase plasma leakage response at 5 h. At 10 min PAF given intra-arterially produced a similar leakage into the tissue but less into the lumen compared to topical PAF. Intravenous PAF produced additional effects such as pulmonary oedema. Carbachol 8-16 nmol had only minimal effects on 'leakage' but produced severe bronchoconstriction. Toluene diisocyanate (0.003-0.03 microliter) produced dose-dependent and very sustained (17 h) plasma leakage. Recovery of plasma tracers in airway tissue and surface liquids, respectively, was significantly correlated. As examined with capsaicin, absorption of luminal macromolecules increased only slightly during the exudation process. It is suggested that the consistent inflammatory stimulus-induced passage of plasma into the lumen is a consequence of a load on the basal side of the epithelium induced by the extravasated plasma and its derived peptides. An increased interstitial pressure may transiently separate many epithelial cells allowing a mainly uni-directional almost unrestricted flow of large solutes into the lumen.

Topics: Allergens; Animals; Erythrocytes; Fibrinogen; Fluorescein-5-isothiocyanate; Guinea Pigs; In Vitro Techniques; Inflammation; Iodine Radioisotopes; Male; Mucous Membrane; Respiratory System; Serum Albumin, Radio-Iodinated; Sodium Pertechnetate Tc 99m; Trachea

Radionuclide imaging is the diagnostic procedure of choice for evaluation of acute disorders of the scrotum, permitting rapid differentiation of torsion of the spermatic cord from inflammatory processes. The method is less successful in diagnosing torsion of the testicular appendages. In the majority of reported cases of torsion of the appendix testis the scan appears normal. In a very limited number of cases increased perfusion to the affected side has been noted. We report a case of metachronous torsion of both the appendices testis. In each instance, there was decreased tracer uptake on the affected side, suggestive of early torsion of the testicle. The sequential involvement of each testis with a nine month interval between respective torsions provides a unique example where each testis serves, sequentially, as a normal control for the torsed contralateral appendage.

Topics: Child; Diagnosis, Differential; Humans; Inflammation; Male; Radionuclide Imaging; Sodium Pertechnetate Tc 99m; Spermatic Cord Torsion

Data are summarized indicating that the degree and duration of antigen induced arthritis (AIA) influences handling of intra-articular (i.a.) antigen. Long term antigen retention was less in chronic as compared with transient joint inflammation, whereas i.a. antigen was cleared more rapidly from the joint in severe than in moderate AIA. In addition, the presence of ungoing AIA enhances initial elimination of i.a. injected antigen from the joint.

Topics: Animals; Antigens; Arthritis; Freund's Adjuvant; Inflammation; Injections, Intra-Articular; Iodine Radioisotopes; Rabbits; Radionuclide Imaging; Serum Albumin, Bovine; Sodium Pertechnetate Tc 99m

Topics: Adolescent; Diagnosis, Differential; Humans; Inflammation; Male; Radionuclide Imaging; Scrotum; Sodium Pertechnetate Tc 99m; Technetium