Biomedical subjects

G Leinsinger

Publications and source records attributed to G Leinsinger.

40 records · Page 3Linked to original sources

PubMed1987

[Radioimmunoscintigraphy with monoclonal antibodies].

Radioimmunoscintigraphy is presented as a new imaging modality in nuclear medicine, using specific antigen-antibody interactions. Monoclonal antibodies to tumor-associated antigens facilitate the characterization of molecular differences between tumors and normal cells. Labelled with gamma-emitting radioisotopes like I-131, I-123, In-111, and Tc99M, these antibodies can be used for in-vivo imaging. Radioimmunoscintigraphy does not compete with morphological modalities like CT and ultrasound, but provides additional information based on its functional principle. Hidden lesions may be detected. Target-to-background ratios, however, are still rather low hampering scintigraphic imaging. The use of Single Photon Emissions Computed Tomography (SPECT) in addition to planar scintigraphy resolves background activities thus providing better visualization and localization of tumors, and increasing sensitivity. The high cost of these time-consuming studies is still a limiting factor to its wider use. Its preliminary indication is founded on the suspicion of tumor progression, based on clinical findings and/or increasing serum tumor markers (CEA, CA 19-9, CA 12-5). This paper provides an overview over possible applications of radioimmunoscintigraphy. Its clinical use is demonstrated by studies of malignant melanoma, colorectal cancer and ovarian cancer.

Antibodies, Monoclonal↗

PubMed1987

[133Xe-DSPECT: normal values of resting cerebral blood flow and reserve capacity].

Using the 133Xe-DSPECT technique, quantitative measurements of regional cerebral blood flow (rCBF) were performed before and after provocation with acetazolamide (Diamox) i.v. in 32 patients without evidence of brain disease (normals). In 6 cases, additional studies were carried out to establish the time of maximal rCBF increase which was found to be approximately 15 min p.i. 1 g of Diamox increases the rCBF from 58 +/- 8 at rest to 73 +/- 5 ml/100 g/min. A Diamox dose of 2 g (9 cases) causes no further rCBF increase. After plotting the rCBF before provocation (rCBFR) and the Diamox-induced rCBF increase (reserve capacity, delta rCBF) the regression line was delta rCBF = -0,6XrCBFR + 50 (correlation coefficient: r = -0,77). In normals with relatively low rCBF values at rest, Diamox increases the reserve capacity much more than in normals with high rCBF values before provocation. It can be expected that this concept of measuring rCBF at rest and the reserve capacity will increase the sensitivity of distinguishing patients with reversible cerebrovascular disease (even bilateral) from normals.

Acetazolamide↗

PubMed1984

Dynamic SPECT with Xe-133: regional cerebral blood flow in patients with unilateral cerebrovascular disease: concise communication.

To validate xenon-133 dynamic single photon emission tomography (SPECT) clinically, 74 patients were examined. Strictly unilateral cerebrovascular disease was confirmed in 47 patients by clinical history and by transmission computerized tomography (TCT) and contrast angiography. Twenty-seven were excluded, considered normal. SPECT flow maps were evaluated visually (against TCT) or by automated region of interest (ROI) techniques (12 areas per slice) to measure area flow (AF) (ml/100 g-min) and interhemispherical area flow ratios (AR). These were compared with normal values. Minimum AF in affected hemisphere decreased, and AR-to-normal difference increased, with the severity of the disease. Visually, low-flow areas were detected twice as frequently in SPECT as areas of low density of TCT. In reversible episodes, sensitivity of AF alone ws significantly below the sensitivity of combined evaluation of flow and ratio.

Adult↗

PubMedDate not supplied

Superior temporal gyrus and P300 in schizophrenia: a combined ERP/structural magnetic resonance imaging investigation.

Decrement of the auditory P300 component of the event-related potentials (ERP) is a robust finding in schizophrenic patients and seems to be most pronounced in the left temporal region. Structural MRI studies support the hypothesis that regional structural brain differences in this patient group include reduced volume in temporal lobe structures. The aim of the presented study was to investigate the possible gray matter volume reductions in the left posterior superior temporal gyrus (STG) and the P300 reduction and left <right topographic asymmetry in schizophrenic patients. Therefore, in 50 male schizophrenic patients and 50 age- and educational level-matched male controls, auditory ERPs and structural MRI measurements of the gray matter volume of the STG were assessed. In the group of patients, the psychopathological symptom of thought disorder was correlated with the electrode site T3 and underlying gray matter of the left posterior superior temporal gyrus. The subgroup of patients with pronounced negative symptoms was analyzed with respect to ERP and structural MRI measurements. Our data revealed no evidence for a reduction of P300 amplitude or left STG gray matter volume in schizophrenic patients. However, the higher amount of thought disorders was related to a small T3 amplitude. No associations between the electrophysiological and structural measurements could be detected. There were also no significant reductions of ERP and MRI measurements within the subgroup of patients with pronounced negative symptoms.

Adult↗