[Perfusion brain imaging with SPECT-technique. German Guideline S1]. / Hirnperfusions-SPECT mit 99mTc-Radiopharmaka. DGN-Handlungsempfehlung (S1-Leitlinie).

This paper describes the guideline for perfusion brain imaging with SPECT-technique published by the Association of the Scientific Medical Societies in Germany (AWMF).The purpose of this guideline is to provide practical assistance for indication, examination procedures, findings and their interpretation also reflecting the present state of the art. Information and instruction are given regarding indication, preparation of the patients and examination procedures of brain perfusion SPECT, including preparation and quality control of the tracer as well as the radiation dosimetry, technical performance of image acquisition with the gamma-camera and image processing. Also advices for interpretation of findings are given. In addition, possible pitfalls are described.

Induction of HPRT- mutants in Chinese hamster V79 cells after heavy ion exposure.

The induction of resistance to 6-thioguanine by heavy ion exposure was investigated with various accelerated ions (oxygen-uranium) up to linear energy transfer (LET) values of about 15,000 keV/microns. Survival curves are exponential with fluence; mutation induction shows a linear dependence. Cross-sections (sigma i: inactivation, sigma m: mutation) were derived from the respective slopes. Generally, sigma i rises over the whole LET range, but separates into different declining curves for single ions with LET values above 200 keV/microns. Similar behaviour is seen for sigma m. The new SIS facility at GSI, Darmstadt, makes it possible to study the effects of ions with the same LET but very different energies and track structures. Experiments using nickel and oxygen ions (up to 400 MeV/u) showed that inactivation cross-sections do not depend very much on track structure, i.e. similar values are found with different ions at the same LET. This is not the case for mutation induction, where very energetic ions display considerably smaller induction cross-sections, compared with low-energy ions of identical LET. Preliminary analyses using the polymerase chain reaction (PCR) demonstrate that even heavy ions cause "small alterations" (small deletions or base changes). The proportion of the total deletions seems to increase with LET.

Sympathetic re-innervation after heart transplantation: dual-isotope neurotransmitter scintigraphy, norepinephrine content and histological examination.

Cardiac transplantation entails surgical disruption of the sympathetic nerve fibres from their somata, resulting in sympathetic denervation. In order to investigate the occurrence of sympathetic re-innervation, neurotransmitter scintigraphy using the norepinephrine analogue iodine-123 metaiodobenzylguanidine (MIBG) was performed in 15 patients 2-69 months after transplantation. In addition, norepinephrine content and immunohistochemical reactions of antibodies to Schwann cell-associated S100 protein, to neuron-specific enolase (NSE) and to norepinephrine were examined in 34 endomyocardial biopsies of 29 patients 1-88 months after transplantation. Anterobasal 123I-MIBG uptake indicating partial sympathetic re-innervation could be shown in 40% of the scintigraphically investigated patients 37-69 months after transplantation. In immunohistochemical studies 83% of the patients investigated 1-72 months after transplantation showed nerve fibres in their biopsies but not positive reaction to norepinephrine. Significant norepinephrine content indicating re-innervation could not be detected in any biopsy. It was concluded that in spite of the lack of norepinephrine content there seemed to be immunohistological and scintigraphic evidence of sympathetic re-innervation. An explanation for this contradictory finding may be the reduced or missing norepinephrine storage ability compared to the restored uptake ability of regenerated sympathetic nerve fibres.

Flow cytometric detection of unbalanced ram spermatozoa from heterozygous 1;20 translocation carriers.

Flow cytometric analysis of enzymatically decondensed, DAPI-stained spermatozoa was performed to confirm the suspected production of unbalanced spermatozoa in heterozygous rams carrying a 1;20 translocation. High-precision flow cytometry (coefficient of variation, 0.6-0.8%) with a PAS II flow cytometer depicted Y- and X-chromosome-bearing spermatozoa from three cytogenetically normal rams as two distinct peaks. The difference in DNA fluorescence intensity between the gonosomes averaged 4.8%. Analysis of sperm samples from three heterozygous 1;20 translocation carriers yielded histograms with five peak distributions. The individual peaks were attributed to spermatozoa with a normal, balanced, and unbalanced chromosomal status. Peaks within Y- and X-spermatozoa populations were distributed in a ratio of 1:2:1 and were almost completely separated, with a coefficient of variation of 0.5-0.6%. Owing to the relative size of the translocated chromosomal segment (2.4% of the total DNA content, as determined from the flow cytometric data), histograms with five instead of the expected six peaks were observed.

Mutation induction in mammalian cells by very heavy ions.

V79 Chinese hamster cells were exposed to heavy ions (O to U) and assayed for mutants at the HGPRT-locus by incubation in selective medium containing 6-thioguanine. The LET ranged from 300 to 18000 keV/micrometer. Mutants could be recovered from all particle radiation but the effectivity per deposited energy decreased with atomic numbers greater than 8. The results are discussed with regard to fundamental processes of cell reactions to very heavy ions and with respect to possible implications for hazard estimations.

Mutation induction in V79 Chinese hamster cells by very heavy ions.

Mutation induction (resistance to 6-thioguanine) in Chinese hamster fibroblasts (V79) by exposure to accelerated heavy ions (O, Ne, Ca, Ti, Ni, Xe, Pb and U with energies between 5 and 14.8 MeV/u) was investigated, covering a range of LET from 300 to about 15,700 KeV/micron. The LET-dependence of the mutation induction cross-section (sigma m) has, in a similar way to inactivation (sigma i), to be described by separate curves for each ion. Both sigma m and mutagenicity (sigma m/sigma i) decrease with increasing specific energy for any given ion. Relative biological effectiveness for mutation induction was found to be significantly smaller than unity for the ions and energies investigated.