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Biomedical subjects

I Kämpfer

Publications and source records attributed to I Kämpfer.

At least 19 recordsLinked to original sources
PubMed2003

Efficacy and safety of inhaled recombinant interleukin-2 in high-risk renal cell cancer patients compared with systemic interleukin-2: an outcome study.

Systemic IL-2 is an effective treatment for low to intermediate risk mRCC patients, its efficacy is marginal in high-risk cases. Therefore, other treatment approaches are required for this population. Ninety-four high-risk patients with RCC and pulmonary metastases were treated with inhaled plus concomitant low-dose subcutaneous rhIL-2. Clinical response, survival and safety were compared with those from IL-2 given systemically at the registered dose and schedule in 103 comparable historical controls. In the rhIL-2 INH group, treatment consisted of 6.5 MIU rhIL-2 nebulized 5x/day and 3.3 MIU rhIL-2 SC once daily. The rhIL-2 SYS group received treatment which consisted of intravenous infusion of 18.0 MIU/m2/day rhIL-2 or SC injection of 3.6-18.0 MIU rhIL-2. Some patients in both groups also received IFNalpha. Mean treatment durations were 43 weeks rhIL-2 INH and 15 weeks rhIL-2 SYS. Significantly longer overall survival and progression-free survival durations were observed in the rhIL-2 INH group. The probability of survival at 5 years was 21% for the rhIL-2 INH group. No patients survived 5 years in the rhIL-2 SYS group. A multivariate analysis of overall survival adjusting for differences in baseline characteristics between the two treatment groups resulted in a risk ratio of 0.43 (95% CI 0.30-0.63; P < 0.0001). The data suggested an association between the response (SD or better) and survival, especially in the rhIL-2 INH group. The inhalation regimen was well tolerated. This outcome study suggests that administration of rhIL-2 by inhalation is efficacious and safe in high-risk mRCC patients with pulmonary metastases, who have no other treatment option available.

Administration, Inhalation↗
PubMed2000

In vivo [125I]-iodobenzovesamicol binding reflects cortical cholinergic deficiency induced by specific immunolesion of rat basal forebrain cholinergic system.

In this study, radiolabeled iodobenzovesamicol (IBVM), which is known to bind with high affinity to the vesicular acetylcholine transporter, was tested for its usefulness in imaging cortical cholinergic deficits in vivo. To induce reductions in cortical cholinergic input, the cholinergic immunotoxin 192IgG-saporin was employed. This has been shown to selectively and efficiently destroy basal forebrain cholinergic neurons in rats. The efficiency of the immunolesion was verified by histochemical acetylcholinesterase staining. [125I]-IBVM binding before and after lesioning was measured using autoradiography. Basal forebrain cholinergic cell loss resulted in a considerable reduction in [125I]-IBVM binding in the cholinoceptive target regions, but not in the striatum and cerebellum, brain regions that do not receive a cholinergic input by the basal forebrain cholinergic nuclei, suggesting that [123I]-IBVM has potential in imaging cortical cholinergic deficits in vivo, at least in animals.

Acetylcholinesterase↗
PubMed1999

Systemic characteristics of chronic arthritis induced by transfer of human rheumatoid synovial membrane into SCID mice (human/murine SCID arthritis).

Erosive human/murine (hu/mu) SCID arthritis, caused by unilateral engrafting of human rheumatoid arthritis synovial membrane (RA-SM) in the knee joints of SCID mice, was monitored for up to 18 weeks by scintigraphic, radiological, morphological and immunohistochemical analyses.(99m)Tc-DPD scintigraphy and histology revealed secondary, oligoarticular spreading of arthritis to contralateral knees and hips, but not to forelimb joints. Also, there were no extraarticular manifestations. At 18 weeks, surviving human cells were found within the pannus, but not directly at the cartilage erosion front, where fibroblast-like cells and macrophages of murine origin predominated. The latter cells also predominated in secondarily affected joints, where no human cells were detectable. Preventive depletion of murine NK-cells by anti-asialo-GMI antibodies, to check the influence of NK cells independently of strain and MHC system, combined with application of autologous human PBMN cells, had virtually no effects on the disease process. The completeness of the SCID defect was not critical, i.e. T cells were completely absent in the organs examined, and the presence of a few B cells in the spleen did not correspond to particular disease features. The SCID defect itself had a clear impact, since, in the chronic phase, SCID.bg and RAG-2(-/-)knockout mice developed less consistent pathological/scintigraphic signs of disease than SCID mice. Thus, unilaterally-induced hu/mu SCID arthritis is an oligoarticular disorder of the hindlimbs. Murine macrophages and fibroblast-like cells appear responsible for tissue destruction in engrafted and non-engrafted arthritic joints.

Animals↗
PubMed1999

Iodo-QNB cortical binding and brain perfusion: effects of a cholinergic basal forebrain lesion in the rat.

This study deals with the question of whether in vivo application of [125I]iodo-quinuclidinyl-benzilate (QNB) is able to demonstrate changes in cortical muscarinic receptor density induced by a cholinergic immunolesion of the rat basal forebrain cholinergic system, and whether the potential effects on IQNB distribution in vivo are also associated with effects on regional cerebral perfusion. Immunolesioned and control animals were injected with (R,S) [125]iodo-QNB and with [99mTc]-d,l-hexamethylpropyleneamine oxime (HMPAO). The cerebral distribution of both tracers was imaged using double tracer autoradiography. Impaired cholinergic transmission was paralleled by a 10-15% increase of [125I]iodo-QNB binding in the regions of cortex and hippocampus. The local cerebral blood flow remained unchanged after cholinergic lesion.

Acetylcholine↗
PubMed1999

Improvement of brain SPECT by stabilization of Tc-99m-HMPAO with methylene blue or cobalt chloride. Comparison with Tc-99m-ECD.

AIM: This present study was carried out to investigate whether stabilization of Tc-99m-HMPAO with methylene blue (MB) or cobalt chloride (CC) causes a sensible improvement in image quality and how cerebral to noncerebral activity ratios compare with those of Tc-99m-ECD. METHODS: 30 minutes after preparation 400-600 MBq unstabilized Tc-99m-HMPAO (N = 35 patients), Tc-99m-HMPAO added with MB (N = 24 patients), added with CC (N = 30 patients) or Tc-99m-ECD (N = 28 patients) were injected. Radiochemical stability was measured in vitro with three chromatographical methods. Image quality was assessed quantitatively using two ratios, one of them determined by count densities of brain/scalp (Os), the other one by count densities of brain/nose (QN). In addition, image quality (0 = bad, 3 = excellent) and background activity (0 = high, 3 = no) were visually assessed by three independent observers. RESULTS: In contrast to unstabilized Tc-99m-HMPAO the integrity of the complexes of MB-Tc-99m-HMPAO, CC-Tc-99m-HMPAO and Tc-99m-ECD decreased only by a few percent during a period of 2 hours after reconstitution (66.8 +/- 9.9 vs. 93.0 +/- 2.5, 91.8 +/- 1.9 and 96.9 +/- 1.4%, p < 0.001). Qs and Qn (m.v. +/- SD) differed significantly between studies using unstabilized Tc-99m-HMPAO (3.0 +/- 0.4 and 2.1 +/- 0.3), MB-Tc-99m-HMPAO (3.4 +/- 0.4 and 2.3 +/- 0.3), CC-Tc-99m-HMPAO (3.6 +/- 0.6 and 2.6 +/- 0.4) and those using Tc-99m-ECD (4.3 +/- 0.7 and 4.8 +/- 1.4, p < 0.05 and < 0.001). Stabilization with CC or MB resulted in significant higher scoring of image quality and lower scoring of background activity in comparison to that of unstabilized Tc-99m-HMPAO, without reaching the scores obtained with Tc-99m-ECD. CONCLUSIONS: It is concluded that stabilization of Tc-99m-HMPAO with MB or CC definitely improves image quality in rCBF-SPECT, without reaching that of Tc-99m-ECD. Improvement of image quality results from the reduction of the amount of decomposition products that contribute to considerable extracerebral activity.

Adult↗
PubMed1998

Human leptin forms complexes with alpha 2-macroglobulin which are recognized by the alpha 2-macroglobulin receptor/low density lipoprotein receptor-related protein.

OBJECTIVE: To identify binding proteins of leptin in human plasma. METHODS: Binding was evaluated by electrophoresis, size exclusion chromatography (SEC), Western blotting, and radioisotope labeling. Quantification of leptin and the different forms of alpha2-macroglobulin (alpha2-M) was performed by ELISA. RESULTS: Leptin interacts with the proteinase inhibitor, alpha2-M. 125I-labeled leptin specifically binds to the transformed inhibitor, which arises by reaction with proteinases or with reactive primary amines. No leptin binding was observed to the native alpha2-M, which abundantly occurs in plasma. The complex formation between leptin and alpha2-M was found to proceed within minutes and was stable, as it resisted separation by SEC and electrophoresis. The Kd of the complex was 2.14 +/- 0.78 micromol/l. Complex formation with transformed alpha2-M did not interfere with the immunological determination of leptin in plasma. The leptin-alpha2-M complex was found to be recognized by the alpha2-M receptor/low density lipoprotein receptor-related protein. By computer analysis, a simple model is presented showing that the degree of transformation of alpha2-M may significantly influence the leptin concentration in blood. CONCLUSIONS: The proteinase inhibitor, alpha2-M, may act as a leptin-binding protein in human plasma. Binding of leptin to transformed alpha2-M and its rapid clearance by the alpha2-M receptor may significantly influence the bioavailability of leptin in human plasma.

Adult↗
PubMed1997

[Striatal uptake of I-123-beta-CIT and I-123-IBZM in patients with extrapyramidal symptoms].

AIM: This pilot study deals with the question whether characteristic changes in local cerebral dopamine transporter function and D2-receptor binding capacity can be shown with SPET in idiopathic Parkinson syndrome (IPS) and secondary Parkinson syndrome (SPS). METHODS: In 16 patients (6 with IPS, 6 with SPS except Wilson's disease, and 4 with Wilson's disease) SPET studies were performed using I-123-beta-CIT and I-123-IBZM and a dual-head gamma camera. Images were obtained 20-24 h and 2 h post injection, respectively. For semiquantitative analysis count density ratios of basal ganglia (BG) and cerebellum (CER) were determined for I-123-beta-CIT and ratios between BG and medial frontal cortex (MFC) for I-123-IBZM. RESULTS: The BG/CER ratio in the I-123-beta-CIT studies averaged 3.04 +/- 0.83 in IPS and 7.73 +/- 3.28 in SPS (p < 0.01) (except Wilson's disease). In patients with IPS, the BG/MFC I-123-IBZM ratios of basal ganglia contralateral to the symptomatic side exceeded that of the individual ipsilateral BGs (1.75 +/- 0.12 vs. 1.61 +/- 0.16); these ratios were significantly reduced when compared with those of SPS patients, although the differences were less pronounced than those of I-123-beta-CIT uptake values. In some of the patients with Wilson's disease the BG/MFC ratio for I-123-IBZM was dramatically reduced (as low as 1.29), whereas I-123-beta-CIT uptake was only slightly reduced when compared with that of SPS patients (8.00 +/- 2.90, p < 0.01). CONCLUSION: It is concluded that the neurochemical changes that can be anticipated in the above diseases can be monitored with SPET. I-123-beta-CIT, however, appears to be more adequate to differentiate IPS from SPS than I-123-IBZM.

Adult↗
PubMed1996

Orthotopic implantation of inflamed synovial tissue from RA patients induces a characteristic arthritis in immunodeficient (SCID) mice.

The objective of this work was to study in more detail the human/murine SCID arthritis model with special emphasis on characteristic features initiated by rheumatoid arthritis (RA) synovial membrane (SM) as compared to appropriate control tissues. Small tissue samples from RA-SM, healthy lymph node, healthy SM, and granulomatous tissue of human origin were implanted into the left knee joint of mice with severe combined immunodeficiency (SCID), and the joints were analysed histologically after 7 days. In addition, a time course study, including non-invasive monitoring by serological parameters (human IgM, IgG, and IL-6) and Tc-99m-scintigraphy, was performed for up to 4 weeks on RA-SM recipients. All tissue implants induced transient exudative joint inflammation while RA-SM initiated a characteristic arthritis with pannus tissue of high cellular density, erosion, multinuclear giant cells, lining cell hyperplasia, fibroblast-like cell layers, chondroideal metaplasia, and fibrin deposits. Significantly elevated levels of human immunoglobulin and characteristic signs of chronic inflammation persisted for more than 4 weeks. We conclude that the hu/mu SCID arthritis with RA-SM implants comprises features of non-specific inflammation which is also transiently seen with control tissues but develops characteristic features of chronic RA-like synovitis thereafter.

Animals↗
PubMed1996

Radioiodination of nicotine with specific activity high enough for mapping nicotinic acetylcholine receptors.

A novel radiochemical method is presented to synthesize 5-[123I/125I/131I]-dL-nicotine by radioiodination of 5-bromonicotine. Radioiodination of the precursor 5-dL-bromonicotine was achieved using a copper (I)-assisted nucleophilic exchange reaction in the presence of reducing agent. The reaction conditions were optimized by varying pH, concentration of Sn(II) salt, ascorbic acid, Cu(I)chloride and reaction temperature. After purification by high-performance liquid chromatography the radiochemical purity of the product exceeded 98%, with a radiochemical yield of 55% and a specific activity > or =5 GBq/micromol. Specific binding of the iodinated nicotine was demonstrated in rat brain by autoradiography. The radioactivity from the specific structures was displaced by an excess of non-radioactive nicotine (10(-3)M) with KD and Bmax of 13.1+/-7.8 nM and 22+/-2.7 fmol/mg protein and unspecific binding of about 40%. The in vivo distribution of 5-[131I]iodonicotine was determined in 20 female Wistar rats at various time intervals of 15s to 90 min post injection (p.i.) by well counting and autoradiography. Brain activity peaked within 0.5 min p.i., and then showed a biexponential washout. Initially, activity within the cerebral cortex exceeded that of the cerebellum by a factor of 1.5-2.0. It was also increased in the striatum and thalamus. However, as soon as 15 min p.i. activity was almost homogeneously distributed. In conclusion, synthesis of 5-iodo-dL-nicotine (labelled with 131I, 125I or 123I, respectively) with appropriately high specific activity for receptor studies was achieved and specific binding to nicotine receptors in rat brain was demonstrated; following intravenous injection, however, there is considerable unspecific binding, obviously due to highly flow-dependent tissue retention.

Animals↗
PubMed1992

[Local 133xenon clearance in the eye and comparative in vitro wash-out time determination in patients with monoclonal gammopathy].

The authors investigated the dependence of the local clearance of 133xenon to the viscosity of the blood. Increase of viscosity of blood compared with decrease of local clearance of 133xenon by patients with monoclonal gammopathy were demonstrated. It was also shown that using the Beta-part of radiation of 133xenon is sufficient for looking for wash-out-times of the anterior eye segment. However, use of 133xenon in isotonic solution is also possible in other ophthalmological diseases for differentiation.

Animals↗
PubMed1991

[Animal experiment studies of the distribution and elimination of radioactively marked endotoxin].

We were able reproduce typical morphological and laboratory changes of endotoxinemia in dogs and small experimental animals by administration of E. coli = 111 K58 endotoxin labelled with 99m Tc. Contrary to the literature our distribution studies in rats showed a high concentration of endotoxin in the kidney. An effective endotoxin elimination was possible by extracorporal hemoperfusion in vitro and vivo. Optimal results were achieved using immunoabsorption in combination with plasmapheresis. However, further experimental studies are necessary to clarify the problem fully.

Animals↗
PubMed1986

Binding of 113mIn ion to human erythrocytes.

The 113mIn ion is tightly bound to hemoglobin; less than 20% of the total amount of 113mIn present in the red cells are attached to the stroma. The extraction of the heme from purified hemoglobin with HCl/acetone mixture showed 99% of the 113mIn activity in the heme fraction. In comparison to the 51Cr and 99mTc isotopes known to be bound to the beta-chain of globin only, 20 and 30%, respectively, of their activities were found in the heme fraction. Acetyl acetone is necessary for effective labelling of erythrocytes with 113mIn. Only 7% of the acetyl acetone applied were found in the cells associated with the heme. It is not involved in the binding of 113mIn to hemoglobin, but facilitates the transport of the 113mIn ions into the cells.

Chromium Radioisotopes↗
PubMed1984

[The chemistry of indium complexes].

There are no complexes of indium known to occur naturally in the human. Several radiopharmaceuticals labelled with In-111 or In-113m have been investigated for their application to localization studies. Most of the indium radiopharmaceuticals have a weak thermodynamic stability and, therefore, no specificity. It is known that such compounds are converted in vivo to In-labelled transferrin. Experiments to increase the thermodynamic stability, thereby leading to an increase in specificity have been followed up in two directions: Modification of polyaminocarboxylic acids (e.g. EDTA, DTPA) by reaction with a benzene diazonium salt or by substitution with methylene phosphoric acid instead of acetic acid in the EDTA molecule. Application of lipid soluble chelates of indium-111 for blood cell labelling (e.g. erythrocytes, leucocytes and platelets). The results are promising.

Blood Cells↗