Biomedical subjects

F H Corstens

Publications and source records attributed to F H Corstens.

At least 73 records · Page 4Linked to original sources

PubMed1998

Tumor retention of 186Re-MAG3, 111In-DTPA and 125I labeled monoclonal antibody G250 in nude mice with renal cell carcinoma xenografts.

UNLABELLED: In radioimmunotherapy of solid tumors substantial gain might be achieved by carefully selecting the radionuclide and the linker connecting it to the antibody. In contrast to 131I, radiometals such as 90Y and 111In may be retained in the tumor cell after internalization of the antibody, thereby enhancing the radiation dose to the tumor. The physical properties of 186Re with 1.08 MeV beta-emission (71%) and 137 keV gamma-emission (10%) seem ideal for radioimmunotherapy. In this study we investigated in nude mice with s.c. renal cell carcinoma xenografts the biodistribution and the retention in the tumor of 186Re-MAG3 labeled monoclonal antibody (mAb) G250 as compared to 111In-DTPA-G250, to 125I-G250 and to 131I-MN14 (non-specific control mAb). Radiolabeled antibody preparations were i.v. injected. Seventy two hours p.i. the biodistribution of the radiolabel was determined. Blood levels of all mAb G250 preparations were remarkably low (mean: 2.38, 1.40 and 1.43% ID/g for 125I, 111In and 186Re respectively) whereas blood levels of mAb MN14 were significantly higher (mean: 12.3% ID/g), indicating tumor processing of mAb G250. Retention of 111In in the tumor was significantly higher than of 186Re and 125I whereas retention in the tumor of 186Re and 125I did not differ significantly. CONCLUSION: In contrast to other radiometals such as 111In and 90Y, 186Re is not retained in the tumor cell. Therefore 186Re has no additional advantage for radioimmunotherapy with respect to retention in the tumor.

Animals↗

PubMed1998

Acute myelofibrosis mimicking multiple bone metastases on Tc-99m MDP bone imaging.

PURPOSE: Tc-99m bone scintigraphy is widely used for evaluation of osseous spread of malignant tumors. PATIENT: A 60-year-old man had multiple areas of increased uptake on a bone scan in a pattern considered characteristic for extensive metastatic disease. However, a primary neoplasm could not be identified. Finally, acute myelofibrosis--a rare, fatal myeloproliferative syndrome--was diagnosed. CONCLUSION: To avoid delays and extensive diagnostic procedures, acute myelofibrosis should be considered in the differential diagnosis of bone scans showing multiple hot spots. In such cases, a diagnosis can be made on an a tissue sample.

Acute Disease↗

PubMed1998

The kinetics of radiolabelled interleukin-8 in infection and sterile inflammation.

Radiolabelled interleukin-8 (IL-8) is a promising agent for the imaging of infection and inflammation. Several experiments were performed to explore further the imaging potential of radiolabelled IL-8. IL-8 was radioiodinated via the Bolton-Hunter method. Rabbits with focal infection (Escherichia coli, Staphylococcus aureus) or sterile inflammation (zymosan) were injected intravenously with 18.5 MBq (0.5 mCi) of 123I-IL-8. In separate studies, rabbits were injected intravenously with 111In-granulocytes with or without 125I-IL-8. Gamma camera images were obtained at 5 min, 1, 4 and 8 h post-injection (p.i.). Biodistribution was determined at 8 h p.i. In all models, the biodistribution of 123I-IL-8 was characterized by rapid blood clearance and high uptake in infection and sterile inflammation. All foci could be clearly visualized within 4 h p.i. Ex vivo abscess-to-contralateral muscle ratios increased to 114.7+/-23.0 (E. coli), 52.3+/-24.5 (S. aureus) and 49.8+/-8.3 (zymosan) at 8 h p.i. In the circulation, most 123I-IL-8 was bound to erythrocytes. The abscess uptake of 125I-IL-8 reached high levels despite reduced migration of granulocytes towards the site of infection due to the anti-inflammatory activity of intravenously injected IL-8. IL-8 could be injected without induction of neutropenia at a dosage of 2 ng kg(-1). In conclusion, the characteristics of radiolabelled IL-8 for imaging of infection and sterile inflammation are highly encouraging and warrant further optimization for clinical application.

Animals↗

PubMed1998

Dynamic distribution and dosimetric evaluation of human non-specific immunoglobulin G labelled with 111In or 99Tcm.

This study presents data on the dynamic distribution and dosimetry of 111In- and 99Tcm-labelled human non-specific immunoglobulin G (IgG), two recently developed radiopharmaceuticals for the detection of infection and inflammation. Five healthy volunteers were injected with 20-75 MBq 111In-IgG and seven patients were injected with 740 MBq 99Tcm-hydrazinonicotinamide derivative (HYNIC)-IgG. Blood samples, urine and feces were collected. Whole-body gamma camera imaging studies were performed. The activity in source organs was quantified using the conjugate view counting method and a partial background subtraction technique. Dosimetric calculations were performed using the MIRD technique. For 111In-IgG, the mean biological half-times in the blood were 0.90 and 46 h for the a- and b-phase, respectively. For 99Tcm-HYNIC-IgG, these half times were 0.46 and 45 h. For 111In-IgG, the mean cumulative urinary excretion in the first 48 h was 18% of the injected dose, while excretion in the feces was less than 2% of the injected dose. For 99Tcm-HYNIC-IgG, the whole-body retention was always 100% up to 24 h. The mean absorbed doses in the liver, spleen, kidneys, red marrow and testes from 111In-IgG were 0.8, 0.7, 1.2, 0.3 and 0.4 mGy MBq-1 respectively. The mean absorbed doses for 99Tcm-HYNIC-IgG to these organs were 16, 24, 15, 10 and 22 mu Gy MBq-1 respectively. The mean effective dose was 0.25 mSv MBq-1 and 8.4 mu Sv MBq-1 for 111In-IgG and 99Tcm-HYNIC-IgG respectively. In conclusion, the radiation absorbed doses for both 111In-IgG and 99Tcm-HYNIC-IgG are low and, therefore, these radiopharmaceuticals can be administered safely from a radiation risk perspective.

Adult↗

PubMed1998

Technetium-99m labeled to human immunoglobulin G through the nicotinyl hydrazine derivative: a clinical study.

UNLABELLED: A novel method to label polyclonal human immunoglobulin G (IgG) with 99mTc through the nicotinyl hydrazine derivative (HYNIC) has shown promising results in the detection of experimental infection. In this study, 99mTc-labeled HYNIC-IgG was directly compared to (111)In-labeled diethylenetriaminepentaacetic acid (DTPA)-IgG in patients suspected of infectious or inflammatory disease. METHODS: Thirty-seven patients (22 women and 15 men; mean age = 54 yr, range = 17-78 yr) with 39 suspected infectious or inflammatory foci were prospectively studied. After administration of 740 MBq 99mTc-HYNIC-IgG, imaging was performed at 4 and 24 hr postinjection. To avoid cross-over activity, (111)In-DTPA-IgG was injected 24 hr after 99mTc-HYNIC-IgG and imaged at 4, 24 and 48 hr postinjection. The scintigraphic results were confirmed by microbiological, histological, radiological and clinical methods. RESULTS: Technetium-99m-HYNIC-IgG and (111)In-DTPA-IgG scintigraphy showed 100% concordancy. All 17 patients with proven infection or inflammation (19 foci, mainly localized in the locomotor system) had positive scintigraphic findings. No false-negative scintigrams were recorded. In three patients, the scintigrams were concordantly false-positive. As a result, the sensitivity and specificity of imaging infectious or inflammatory foci with 99mTc-HYNIC-IgG and (111)In-DTPA-IgG in these patients were 100% and 85%, respectively. CONCLUSION: Technetium-99m-HYNIC-IgG scintigraphy is equally as effective as (111)In-IgG scintigraphy for the detection of infection and inflammation. The apparent physical and logistic advantages of 99mTc over (111)In make 99mTc-HYNIC-IgG a promising new radiopharmaceutical for imaging infection and inflammation.

Bacterial Infections↗

PubMed1998

Absolute organ activity estimated by five different methods of background correction.

UNLABELLED: Accurate absorbed dose estimates in radionuclide therapy require patient-specific dosimetry. In patient-based dosimetry, estimation of absolute organ uptake is essential. The methods used should be reasonably accurate as well as easy to perform in routine clinical practice. One of the major sources of uncertainty in quantification of organ or tumor activity from planar images is the activity present in the tissue surrounding the source. METHODS: To estimate organ activity as a function of organ-to-background activity concentration ratio, a cylindrical phantom, filled with 5.6 liters of water was used to simulate the abdomen of a patient. Two other cylinders of 150 ml each, representing the kidneys, were each filled with 19 MBq 99mTC and were positioned in the abdomen phantom. The phantom was imaged with a dual-head gamma camera with the kidneys placed at posterior depths of 1-, 5- and 10-cm at kidney-to-background activity concentration ratios of infinity, 10:1, 5:1 and 2:1. The conjugate view geometric mean counting method was used to quantify activity. Five methods for background correction were applied: (1) no correction; (2) conventional background correction (simple subtraction of the background counting rate from the source region counting rate); (3) Kojima method (background corrected for organ thickness and depth); (4) Thomas method (analytical solution); and (5) Buijs method (background corrected for organ and total-body thickness). RESULTS: Since the results were identical for both kidneys, only the left kidney activity measurements are presented. The accuracy of the five background correction methods is given as the percentage difference between the actual and measured activity in the left kidney. For Method 1, the percentage difference ranged from 2% with an infinite kidney-to-background activity concentration ratio to +413% with a 2:1 ratio. For Method 2, these values ranged from -1% to -80%, for Method 3 from +11% to -18%, for Method 4 from -2% to +120% and for Method 5 from -4% to +39%. CONCLUSION: Even though quantitative SPECT is the most rigorous method for activity quantification in conditions of low organ-to-background activity concentration ratio, planar scintigraphy can be applied accurately if appropriate attention is paid to background correction. Using relatively simple background subtraction methods, the quantitative planar imaging technique can result in reasonably accurate activity estimates (Methods 3 and 5). The use of Kojima's method is preferable, especially at very low source-to-background activity concentration ratios.

Humans↗

PubMed1998

Technetium-99m-labeled liposomes to image experimental colitis in rabbits: comparison with technetium-99m-HMPAO-granulocytes and technetium-99m-HYNIC-IgG.

UNLABELLED: Scintigraphic techniques are routinely used for the evaluation of the extent and severity of inflammatory bowel disease. Currently, the radiopharmaceutical of choice is 99mTc-hexamethyl propyleneamine oxime (HMPAO)-leukocytes. We studied the imaging potential of two recently developed 99mTc-labeled agents, polyethylene glycol (PEG)-coated liposomes and hydrazinonicotinate (HYNIC) IgG, in a rabbit model of acute colitis, and compared them with that of 99mTc-labeled, granulocyte-enriched (>90%), white blood cells. METHODS: Acute colitis was induced in rabbits by retrograde instillation of trinitrobenzene sulfonic acid. After 48 hr, 37 MBq of each radiopharmaceutical was administered intravenously. Gamma camera images were taken at 0, 1, 2, 4, 10 and 24 hr. At 4 and 24 hr postinjection, groups of rabbits were killed, and the uptake of the radiolabel in the dissected tissues was determined. For each affected 5-cm segment, the colitis index (CI, affected-to-normal-colon-uptake ratio) was calculated and correlated to the macroscopically scored severity of inflammation. RESULTS: All three agents visualized the colitis lesions within 1 hr postinjection. The CI correlated with the severity of the abnormalities. With increasing severity, the CI at 4 hr postinjection for liposomes was 3.89+/-0.73, 4.41+/-0.47 and 5.76+/-0.65; for IgG 1.67+/-0.08, 3.92+/-0.44 and 6.14+/-0.65; and for granulocytes 2.90+/-0.09, 6.15+/-0.96 and 9.36+/-3.35. For liposomes, the CI further increased during 24-hr postinjection to 6.56+/-0.84, 8.50+/-0.53 and 10.61+/-1.34, respectively. The CI for the other two agents did not change significantly with time. CONCLUSION: In this rabbit model, 99mTc-labeled granulocytes, IgG and liposomes all rapidly visualized colonic inflammation. Granulocytes and liposomes showed the highest CI. Technetium-99m-labeled PEG-liposomes may be an attractive alternative for labeled leukocytes to image inflammatory bowel disease, because they can be prepared off the shelf and no handling of blood is required.

Animals↗

PubMed1998

Liposomes for scintigraphic imaging: optimization of in vivo behavior.

Liposomes, microscopic lipid vesicles consisting of concentric phospholipid bilayers enclosing discrete aqueous spaces, have been investigated extensively as carries for drugs in attempts to achieve selective deposition and/or reduced toxicity. Liposomes radiolabeled with gamma emitters (67Ga, 111In and 99mTc) have been used for imaging purposes. Liposomes as formulated in the past, are rapidly taken up by cells of the mononuclear phagocyte system, primarily those located in liver and spleen. However, it has been shown during the last two decades that the in vivo behavior of liposomes can be modulated by modifying their formulation. The size and the lipid composition have a major influence on the blood clearance rate, hepatic uptake and splenic uptake of liposomes. The development of long circulating liposomes, in particular coating of the bilayer with polyethyleneglycol (PEG) resulted in liposomes that oppose recognition by the MPS, thus displaying even longer circulatory half-lives. By carefully adjusting the liposomal formulation, the in vivo characteristics of liposomes can be tailored such that they become suitable vehicles for imaging various pathological processes in vivo. Liposomes have been proposed for tumor imaging, for infection imaging and as blood pool markers. Here, the factors that determine the in vivo behavior of liposomes and the current status of liposome-based radiopharmaceuticals are reviewed.

Animals↗

PubMed1997

The effect of antibody protein dose of anti-renal cell carcinoma monoclonal antibodies in nude mice with renal cell carcinoma xenografts.

BACKGROUND: Antibodies preferentially can direct radionuclides to solid tumors. However, antibody uptake in tumors is often highly heterogeneous. This heterogeneity may be overcome by increasing antibody protein dose. METHODS: The biodistribution of increasing protein doses of radioiodinated antirenal cell carcinoma (RCC) monoclonal antibodies (MoAbs) G250 and RC 38 was studied in mice with NU-12 or SK-RC-52 RCC xenografts. In addition, MoAb affinity constants and antigen densities (Scatchard analysis) and MoAb processing (internalization) were determined in vitro. RESULTS: The relative uptake of G250 in NU-12 tumors was very high at low protein doses (125% injected dose/g [%ID/g]), but decreased at higher doses, suggesting tumor saturation. Indeed, saturation of G250 antigen occurred at 3 microg protein. In this model, 9200 G250 determinants per NU-12 cell could be targeted, which is only 6.1% of the 150,000 G250 determinants per NU-12 cell as determined in vitro. The RC 38 uptake in NU-12 tumors remained constant up to the 10 microg dose level (40% ID/g) and decreased at higher doses. RC 38 antigens were saturated at 25 microg of RC 38. With RC 38, 15% of the available RC 38 antigens per NU-12 tumor cell were targeted. In contrast, G250 uptake in SK-RC-52 tumors was very low at low antibody dose (4% ID/g at 1 microg) and increased with increasing protein dose. These differences in G250 biodistribution might be related to differences in the processing of G250 by the tumor cells. CONCLUSIONS: Our studies show that some RCC tumors can be saturated with anti-RCC MoAbs at low (25 microg) to very low (3 microg) protein doses. At nonsaturated doses relatively high tumor uptake can be achieved. Surprisingly, in NU-12 tumors only 6.1% and 15% of the available antigenic sites were targeted at the saturating dose levels with G250 and RC 38, respectively.

Animals↗

PubMed1997

Preferential localization of systemically administered radiolabeled interleukin 1alpha in experimental inflammation in mice by binding to the type II receptor.

Previously, we have shown that systemically administered radiolabeled interleukin 1alpha (IL-1alpha) accumulates preferentially in inflammatory foci in mice. Since inflammation is characterized by influx of leukocytes, which represent IL-1 receptor (IL-1R) positive cells, radiolabeled IL-1 may specifically localize in inflammation by binding to its receptors on infiltrated leukocytes. This hypothesis was tested in a series of studies in mice with acute focal inflammations. Evidence for specific IL-1-IL-1R interaction in induced inflammation was found: microscopic autoradiography revealed that 125I-IL-1alpha localized at the site of inflammatory cells with time; 125I-myoglobin, a similar-sized protein with no known interactions in vivo, was not retained in the inflammation. Furthermore, the uptake 125I-IL-1alpha in inflammatory tissue was significantly lower in neutropenic mice than in immunocompetent mice (0.05+/-0.004 vs. 0.65+/-0.06% ID/g at 48 h after injection, P < 0.0007). Moreover, the uptake of 125I-IL-1alpha at the inflammatory site could be blocked with the anti-IL-1R type II antibody 4E2. At 48 h after injection, the uptake with and without blocking the type II IL-1R was 0.13+/-0.01 and 0. 65+/-0.05% ID/g, respectively (P < 0.0001). These in vivo studies provide evidence that systemically administered radiolabeled IL-1alpha localizes in inflammatory tissue by specific receptor binding, predominantly by binding to the type II IL-1R.

Acute-Phase Reaction↗

PubMed1997

Assessment of bone surrounding implants in goats: ex vivo measurements by dual X-ray absorptiometry.

The aim of the present study is to determine the possibility of measuring the bone mineral density (BMD) around implants by dual energy X-ray absorptiometry (DEXA). Therefore, the trabecular BMD was measured close to 127-600 microns and at a distance from various uncoated and Ca-P-coated implants inserted into the femoral condyle of goals. The implants were left in situ for 12 weeks. In addition, the bone-implant interface was evaluated histologically. For comparative reasons the BMD of non-implanted lateral and medial femoral condyles was also measured. The reproducibility of the measurements, expressed as a coefficient of variation, was found to be 0.44%. Moreover, the regions closest to the implants exhibited a higher BMD than all other regions, and the regions located in the medial condyle showed a higher BMD than the lateral condylar regions. Although the histological sections of the implants in the medial condyle demonstrated more bone contact with the coated than with the uncoated implants, a higher density was measured around the uncoated implants. The results regarding the non-implanted condyles indicated a higher density in the medial than in the lateral condyle. In view of these results, we conclude that BMD around dental implants depends on the location of the implant and that DEXA appears to be an excellent tool for analysing bone-implant reactions.

Absorptiometry, Photon↗

PubMed1997

Autoimmune hyperthyroidism occurring late after radioiodine treatment for volume reduction of large multinodular goiters.

131I treatment is an effective alternative to surgery in patients with a large, (non-)toxic, compressive goiter. Late development of hyperthyroidism after 131I therapy for nontoxic nodular goiter is considered rare. We have seen this complication in 3 of approximately 80 patients treated with radioiodine for volume reduction of a large, multinodular goiter. Three women, aged 60 to 71 years, had large, multinodular goiters causing tracheal compression. They were clinically euthyroid before 131I therapy and had normal free thyroxine (FT4) levels. Serum thyroid-stimulating hormone (TSH) levels were normal in 2 patients and undetectable in 1 patient. Patients 1 and 2 received a single dose of 86 and 48 mCi 131I, respectively. Patient 3 received 20 mCi 131I twice (interval 1 month). Clinical and biochemical thyrotoxicosis with high thyroid radioactive iodide uptake (RAIU) developed 10, 6, and 3 months after 131I therapy, respectively, although at control visits 1 to 3 months earlier, serum TSH and FT4 levels were normal. Thyrotoxicosis responded well to methimazole in all three patients. The late occurrence of thyrotoxicosis, high RAIU, and good response to methimazole argue against thyroiditis as the cause of thyrotoxicosis. Serum levels of TSH receptor antibodies, which were undetectable before therapy (patients 1 and 2), were clearly elevated in all three patients during thyrotoxicosis. This is in favor of autoimmune hyperthyroidism as the cause of thyrotoxicosis. These cases illustrate that severe autoimmune hyperthyroidism may occur several months after radioiodine treatment for nontoxic, multinodular goiter. Information about symptoms of hyperthyroidism and regular control visits in the first year after therapy are important in these patients.

Aged↗

PubMed1997

Organ damage is preceded by changes in protein extravasation in an experimental model of multiple organ dysfunction syndrome.

Our objective was to determine the serial evolution of vascular permeability as measured by protein extravasation in various organs during the development of zymosan-induced multiple organ dysfunction syndrome (MODS). We evaluated the biodistribution of 111Indium-labeled nonspecific polyclonal immunoglobulin G (111In-IgG). On days 2, 5, 8, and 12 after intraperitoneal challenge with 1 mg/g zymosan, mice were killed. Heart, liver, spleen, kidneys, and the mesenteric lymph node complex and tissue samples of muscle, ileum, and colon were dissected free and weighed. 24 h before death, 10 micrograms of IgG labeled with 2 MBq 111In was injected i.v. Relative organ weights (ROW), wet to dry weight ratios (WDR), and a permeability index (PI) were calculated. ROW increased gradually until day 12. WDR also increased gradually in most organs. Lung WDR, however, initially increased, with a subsequent return to normal. Splenic WDR did not change over time. Liver, spleen, ileum, and colon PI were the highest on day 2, followed by a decrease toward normal. Lung PI showed a triphasic course with peak values at days 2 and 12. Mesenteric lymph node complex-PI was continuously elevated. WDR (tissue edema) and PI (protein extravasation) have different courses in various organs. Most organs displayed an early increase in PI, followed by a late decrease, while ROW (organ damage) was still increasing. It appears that organ damage is preceded by an increased protein extravasation.

Animals↗

PubMed1997

Technetium-99m labelled liposomes to image experimental arthritis.

OBJECTIVES: Liposomes sterically stabilised with polyethylene glycol (PEG) labelled with technetium-99m were tested for their ability to image adjuvant arthritis in a rat model. METHODS: Adjuvant arthritis was induced in the ankle joint of the left hind foot by injection of Mycobacterium butyricum in Freund's incomplete adjuvant in the foot pad. Seven days later animals received the following radiopharmaceuticals labelled with 99mTc (a) non-PEG-liposomes, (b) PEG-liposomes or (c) non-specific human polyclonal IgG. For each of the radiopharmaceuticals the in vivo distribution of the radiolabel was monitored both scintigraphically as well as by counting the dissected tissues at two, eight, and 24 hours after injection. RESULTS: The pharmacokinetics of the radiopharmaceuticals differed considerably (halflife in the blood: PEG-liposomes (18 hours) > 99mTc-IgG (3 hours) > non-PEG liposomes (1 hour)). The inflamed focus was visualised with each of the agents. The uptake of each of the radiopharmaceuticals in the inflamed ankle region correlated with their residence time in the blood (inflamed joint uptake: PEG liposomes (1.15% injected dose (ID)/ g) > 99mTc-IgG (0.35% ID/g) > non-PEG-liposomes (0.05% ID/g)). Quantitative analysis of the images showed that the inflamed ankle to background ratio was highest with the PEG-liposomes (7.5 at 24 hours after injection), while with the other two agents this ratio did not exceed 4. CONCLUSION: This study shows that 99mTc-labelled PEG-liposomes may be an excellent agent to visualise arthritis. Increased label uptake in the inflamed joint and increased target to background ratios can be obtained with PEG-liposomes because of their long circulating properties. In addition to their use as vehicles for scintigraphic imaging of arthritis PEG-liposomes might also be used for the site specific delivery of antirheumatic drugs.

Animals↗

PubMed1997

Targeting of renal cell carcinoma with iodine-131-labeled chimeric monoclonal antibody G250.

PURPOSE: Pharmacokinetics, biodistribution, immunogenicity, and imaging characteristics of iodine 131 (131I)-labeled chimeric monoclonal antibody (mAb) G250 (cG250) were studied in patients with renal cell carcinoma (RCC) to determine the therapeutic potential of this antibody. PATIENTS AND METHODS: Sixteen patients with RCC received a single intravenous (IV) infusion of 6 mCi 131I-labeled cG250. Five protein dose levels were investigated (2 to 50 mg). Planar scintigraphic images were acquired, and normal tissue biopsies and tumor samples were obtained of surgery (7 days postinjection). The immunogenicity of cG250 was investigated using a sandwich enzyme-linked immunosorbent assay (ELISA) and dosimetric analysis was performed. RESULTS: In all patients with antigen-positive tumors (n = 13), the primary tumors and all known metastases were clearly visualized. Overall uptake, expressed as the percentage of the injected dose (%ID), in the primary tumors ranged from 2.4 to 9.0. Focally, 131I-cG250 uptake as high as 0.52% ID/g was observed. However, intratumoral uptake was highly heterogeneous. 131I-cG250 uptake in nontumorous tissues remained low. Dosimetric analysis showed that up to .48 Gy/mCi was guided to the primary tumors. Selected "hot areas" within these tumors received up to .72 Gy/mCi. A bone metastasis received .23 Gy/mCi and regional lymph node metastases received .20 Gy/mCi. Minimal human antichimeric antibody (HACA) levels were detected in two of 16 patients. CONCLUSION: 131I-cG250 tumor uptake is among the highest reported in clinical studies with antitumor antibodies in solid tumors. Since tumor-sterilizing levels may be guided to the tumor when high doses 131I-cG250 are administered (> 100 mCi) and cG250 appears to be immunosilent, cG250 is a promising vehicle for radioimmunotherapy in RCC.

Aged↗

PubMed1997

Hip and knee arthroplasty infection. In-111-IgG scintigraphy in 102 cases.

We studied indium-111-labeled immunoglobulin G (In-111-IgG) scintigraphy for evaluation of total hip and knee arthroplasty infection in 100 patients (102 arthroplasties) where infection was suspected (85 total hip and 17 total knee replacements, 23 of which proved to be infected, all but 2 late infections). The sensitivity of In-111-IgG scintigraphy for infection was 1.0, for hip and knee arthroplasties the specificities were 0.8 and 0.5, respectively. False-positive results for infection occurred in cementless total hip arthroplasties up to 14 months after implantation. Aseptic inflammation due to formation of ectopic ossification and foreign-body response, following wear of the polyethylene socket, was responsible for false-positive results. The images should be read in conjunction with radiographs, which reduces the rate of false-positive results. In-111-IgG is a highly sensitive and fairly specific tool for detecting of late infection of total hip and total knee arthroplasties.

Adult↗

PubMed1997

Utility of indium-111-labeled polyclonal immunoglobulin G scintigraphy in fever of unknown origin. The Netherlands FUO Imaging Group.

UNLABELLED: We studied the role of 111In-labeled immunoglobulin (111In-IgG) scintigraphy in different subgroups of patients with fever of unknown origin (FUO). METHODS: During a 2-yr period (January 1992 through January 1994), the internal medicine wards of eight university hospitals in The Netherlands participated in this study. A total of 167 patients with FUO were prospectively included to prevent unintended selection. Fifty-eight patients underwent 111In-IgG scintigraphy. For 23 patients without potentially diagnostic clues (PDCs) or only misleading PDCs, the technique was used as a screening procedure. In 35 patients with PDCs pointing at local inflammation this technique was used when indicated. RESULTS: After diagnostic work-up, infections were found in 17 patients (29%), neoplasms in 6 (10%), noninfectious inflammatory diseases in 14 (24%) miscellaneous disorders in 3 (5%) and no diagnosis in 18 (31%). Indium-111-IgG scintigraphy was helpful in the diagnostic process for patients with PDCs at local inflammation only. The diagnostic yield of this technique in this subgroup was 26%. Infection was found in only 10/41 patients with negative scans. All infections were nonfocal or located in the heart, liver region or urinary tract where physiological uptake obscures possible pathologic uptake. The overall sensitivity and specificity was 60% and 83%, respectively. CONCLUSION: In patients without PDCs for local inflammation, the diagnostic yield of scintigraphic techniques was quite low since no focal inflammation was observed. Therefore, 111In-IgG scintigraphy should not be used as a second-step procedure in the work-up of these subgroup of patients with FUO. In patients with PDCs at local inflammation, 111In-IgG is helpful in the diagnostic process in one-fourth of the patients. This diagnostic yield is comparable with that of the majority of other scintigraphic techniques used in the diagnostic process of patients with FUO.

Adult↗

PubMed1997

Optimization of technetium-99m-labeled PEG liposomes to image focal infection: effects of particle size and circulation time.

UNLABELLED: In previous studies we have shown that liposomes sterically stabilized with polyethylene glycol (PEG), preferentially localize in infectious and inflammatory foci. In this study, we further optimized the formulation of PEG liposomes for infection imaging in a rat model. METHODS: The biodistribution and imaging characteristics of different liposomal formulations labeled with 99mTc were determined in rats with S. aureus infection of the left calf muscle. The influence of liposomal size (mean diameter varying from 90 nm to 220 nm) as well as circulation time (modulated by inclusion of 0-10 mole% phosphatidylserine) were studied. RESULTS: The smallest liposomes displayed improved characteristics for infection imaging: 90-nm liposomes revealed the highest abscess uptake (1.6% +/- 0.4% ID/g, 24 hr postinjection) in combination with the lowest splenic accumulation (6.9% +/- 0.7% ID/g, 24 hr postinjection) as compared to the larger sized preparations. Enhanced abscess-to-blood ratios (4.0 versus 1.3 at 24 hr postinjection) were obtained by including 1.0 mole% phosphatidylserine in the lipid bilayer of the PEG liposomes. However, enhanced blood clearance of these liposomes reduced their absolute abscess uptake. CONCLUSION: These results indicate that the in vivo behavior of PEG liposomes can be modulated to optimize their characteristics for infection imaging.

Abscess↗