Objective measurement of oral function in adults with spinal muscular atrophy.

BACKGROUND: Impairment of bulbar function in adult individuals with spinal muscular atrophy (SMA) usually is not assessed by established motor scores. Measurements of oral function including quantitative muscle and endurance tests are able to detect subtle changes. The aim of this study was to systematically evaluate the measurement of maximum bite force and endurance, maximum tongue pressure and endurance, as well as maximum mouth opening in adult individuals with SMA types 2 and 3. METHODS: Data from oral function tests in 43 individuals were analyzed. Differences in oral function between individuals with different SMA types and numbers of SMN2 copies were tested. Spearman´s rho correlations among oral function measures themselves as well as with established clinical outcome scales were analyzed. RESULTS: The absolute maximum measures of oral function (maximum bite force, maximum tongue pressure, maximum mouth opening) were able to discriminate between individuals with different SMA types, individuals with a different number of SMN2 copies and with different walking abilities. The pairwise correlations of the absolute maximum measures of oral function were fair to moderate in size; the same was true for their correlations with the established motor scores. All correlations assessing endurance measures of oral function were weaker and statistically insignificant. CONCLUSIONS: Among the oral function tests maximum tongue pressure and maximum mouth opening are particulary promising as clinical and sensitive outcome measures for clinical trials. Oral function tests may supplement existing motor scores, in particular concerning specific questions about bulbar function or in severely affected non-ambulatory individuals where mild (treatment-related) changes would otherwise remain undetected. Trial registration DRKS, DRKS00015842. Registered 30 July 2019, https://drks.de/search/de/trial/DRKS00015842.

Mycosands: Fungal diversity and abundance in beach sand and recreational waters - Relevance to human health.

The goal of most studies published on sand contaminants is to gather and discuss knowledge to avoid faecal contamination of water by run-offs and tide-retractions. Other life forms in the sand, however, are seldom studied but always pointed out as relevant. The Mycosands initiative was created to generate data on fungi in beach sands and waters, of both coastal and freshwater inland bathing sites. A team of medical mycologists and water quality specialists explored the sand culturable mycobiota of 91 bathing sites, and water of 67 of these, spanning from the Atlantic to the Eastern Mediterranean coasts, including the Italian lakes and the Adriatic, Baltic, and Black Seas. Sydney (Australia) was also included in the study. Thirteen countries took part in the initiative. The present study considered several fungal parameters (all fungi, several species of the genus Aspergillus and Candida and the genera themselves, plus other yeasts, allergenic fungi, dematiaceous fungi and dermatophytes). The study considered four variables that the team expected would influence the results of the analytical parameters, such as coast or inland location, urban and non-urban sites, period of the year, geographical proximity and type of sediment. The genera most frequently found were Aspergillus spp., Candida spp., Fusarium spp. and Cryptococcus spp. both in sand and in water. A site-blind median was found to be 89 Colony-Forming Units (CFU) of fungi per gram of sand in coastal and inland freshwaters, with variability between 0 and 6400 CFU/g. For freshwater sites, that number was 201.7 CFU/g (0, 6400 CFU/g (p = 0.01)) and for coastal sites was 76.7 CFU/g (0, 3497.5 CFU/g). For coastal waters and all waters, the median was 0 CFU/ml (0, 1592 CFU/ml) and for freshwaters 6.7 (0, 310.0) CFU/ml (p < 0.001). The results advocate that beaches should be monitored for fungi for safer use and better management.

Nano-multilamellar lipid vesicles (NMVs) enhance protective antibody responses against Shiga toxin (Stx2a) produced by enterohemorrhagic Escherichia coli strains (EHEC).

Microlipid vesicles (MLV) have a broad spectrum of applications for the delivery of molecules, ranging from chemical compounds to proteins, in both in vitro and in vivo conditions. In the present study, we developed a new set of nanosize multilayer lipid vesicles (NMVs) containing a unique combination of lipids. The NMVs enable the adsorption of histidine-tagged proteins at the vesicle surface and were demonstrated to be suitable for the in vivo delivery of antigens. The NMVs contained a combination of neutral (DOPC) and anionic (DPPG) lipids in the inner membrane and an external layer composed of DOPC, cholesterol, and a nickel-containing lipid (DGS-NTA [Ni]). NMVs combined with a recombinant form of the B subunit of the Shiga toxin (rStx2B) produced by certain enterohemorragic Escherichia coli (EHEC) strains enhanced the immunogenicity of the antigen after parenteral administration to mice. Mice immunized with rStx2B-loaded NMVs elicited serum antibodies capable of neutralizing the toxic activities of the native toxin; this result was demonstrated both in vitro and in vivo. Taken together, these results demonstrated that the proposed NMVs represent an alternative for the delivery of antigens, including recombinant proteins, generated in different expression systems.

[Congenital myasthenic syndromes in adulthood : Challenging, rare but treatable]. / Kongenitale myasthene Syndrome im Erwachsenenalter : Diagnostisch herausfordernd, selten, aber behandelbar.

The congenital myasthenic syndromes (CMS) represent a heterogeneous group of diseases with a broad spectrum of phenotypes. The common characteristic is an inherited genetic defect of the neuromuscular junction. Although in some patients the specific gene defect remains to be detected, the increasing identification of causative genes in recent years has already provided unique insights into the functionality of structural proteins at the neuromuscular junction. Neonatal and early childhood onset is observed in most CMS subtypes; however, late onset in adolescence or adulthood also occurs and establishing the diagnosis at these stages imposes particular challenges. To enable appropriate therapeutic interventions for an at least in principle treatable condition, determining the genetic cause is warranted. In this overview, the critical clinical and diagnostic features of the different CMS subtypes are presented and illustrated using typical cases. Furthermore, specific diagnostic clues are outlined. Finally, the overlap between CMS and muscular dystrophies is discussed. Illustrating characteristic patient examples, the essential clinical and additional diagnostic findings of various CMS subtypes and special diagnostic indications are presented.

Genetic ancestry effects on the distribution of toll-like receptors (TLRs) genepolymorphisms in a population of the Atlantic Forest, São Paulo, Brazil

The innate immune system governed by toll-like receptors (TLRs) provides the first line of defense against pathogens. Surface-localized TLR1 and TLR6 are known to detect parasite components. TLR encoding genes wereshown to display signatures of recent positive selection in Europeans and might be involved in local adaptation at immune-related genes. To verify the influence of Brazilian population admixture on the distribution of polymorphisms in TLRs, we analyzed the genotype frequencies of 24 polymorphisms distributed across five TLRgenes in a Southeastern Brazilian population where autochthonous cases of malaria occur in small foci oftransmission. The estimation of ancestry showed mainly European ancestry (63%) followed by African ancestry(22%). Mean proportions of European ancestry differed significantly between the genotypes of the TLR1 (I602S) gene and in the TLR6 (P249S) gene. The chance of having the G allele in TLR1 gene increases as Europeanancestry increases as well as the chance of having the T allele in the TLR6 gene. The 602S allele is related to a‘‘hypo-responsiveness’’ possibly explaining the high prevalence of asymptomatic malaria cases in areas of Southeastern Brazil. Our results underline the necessity to include informative ancestry markers in genetic association studies in order to avoid biased results...

["Therapy-resistant polymyositis" - is the diagnosis correct?] / "Therapierefraktäre Polymyositis" ­ stimmt die Diagnose?

We report the case of a 32-year-old woman with severely elevated serum creatine kinase (CK; 80,000 U/l) and progressive proximal pareses. As muscular biopsy showed inflammatory infiltrates, polymyositis was suspected and immunosuppressive treatment was initiated. However, clinical improvement could not be achieved. Gene sequencing of the DYSF-gene showed a previously unreported homozygous mutation. In summary, elevated serum CK and inflammatory infiltrates in the muscle biopsy are not specific for polymyositis, but may also occur in degenerative diseases (muscular dystrophy), such as dysferlinopathy.

[Chronic Inflammatory Demyelinating Polyneuropathy]. / Chronische inflammatorische demyelinisierende Polyneuropathie.

Chronic inflammatory demyelinating polyneuropathy (CIDP) is a chronic progressive or relapsing autoimmune neuropathy with heterogeneous clinical presentation. Symptoms typically include symmetrical, proximal and/or distal paresis and sensory loss. Atypical CIDP variants are increasingly recognized, including subtypes with rapid onset as well as variants with pure sensory, focal or marked asymmetrical deficits. Diagnosis is established by compatible symptoms, characteristic electrophysiological features and cerebrospinal fluid analysis. In unequivocal cases, inflammatory infiltrates in sural nerve biopsy support the diagnosis. Recent studies suggest that diagnostic imaging techniques such as MRI and nerve ultrasound may become useful tools for establishing the diagnosis. First-line therapies include immunoglobulines, steroids, and plasmapheresis. Immunosuppressant agents and monoclonal antibodies are used in therapy-refractory cases or as cortison-saving agents.

Merozoite surface protein-1 genetic diversityin Plasmodium malariae and Plasmodium brasilianum from Brazil

The merozoite surface protein 1 (MSP1) gene encodes the major surface antigen of invasive forms of the Plasmodium erythrocytic stages and is considered a candidate vaccine antigen against malaria. Due to its polymorphisms, MSP1 is also useful for strain discrimination and consists of a good genetic marker. Sequence diversity in MSP1 has been analyzed in field isolates of three human parasites: P. falciparum, P. vivax, and P. ovale. However, the extent of variation in another human parasite, P. malariae, remains unknown. This parasite shows widespread, uneven distribution in tropical and subtropical regions throughout South America, Asia, and Africa. Interestingly, it is genetically indistinguishable from P. brasilianum, a parasite known to infect New World monkeys in Central and South America. Methods: Specific fragments (1 to 5) covering 60 % of the MSP1 gene (mainly the putatively polymorphic regions), were amplified by PCR in isolates of P. malariae and P. brasilianum from different geographic origin and hosts. Sequencing of the PCR-amplified products or cloned PCR fragments was performed and the sequences were used to construct a phylogenetic tree by the maximum likelihood method. Data were computed to give insights into the evolutionary and phylogenetic relationships of these parasites...

[Chemotherapy-induced Peripheral Neuropathy]. / Chemotherapie-induzierte Polyneuropathie.

Chemotherapy-induced peripheral neuropathy (CIPN) is a common and relevant side effect of antineoplastic agents such as cisplatin, paclitaxel, vincristine and bortezomib. Over the last years, significant progress has been achieved in elucidating the underlying pathomechanisms of CIPN using both in vivo and in vitro models. These studies suggest that mitochondrial toxicity, disturbed axonal transport, toxic effects on Schwann cells and activation of the immune system contribute to the pathogenesis of CIPN. This review provides an overview of the current pathogenetic concepts of CIPN. In addition, experimental approaches that aim at preventing or ameliorating neurotoxic effects of antineoplastic agents are discussed.

[25-year old patient with angina pectoris during religious fasting]. / 25-jähriger Patient mit pektanginösen Beschwerden während des muslimischen Fastenmonats.

UNLABELLED: HISTORY AND PRESENTATION AT ADMISSION: A 25-year-old male patient presented with acute left sided chest pain. The patient reported no physical exercise but daytime fasting (with neither food nor liquid intake) which he had started several days before. INVESTIGATIONS: ECG, echocardiography and chest X-ray were normal, but blood examination revealed elevated levels for creatine kinase (CK) and lactate dehydrogenase (LDH). Ischemic lactate ammonia test revealed no increase of lactate during exercise. Muscle biopsy confirmed suspected diagnosis of glycogen storage disease type V (McArdle's disease). TREATMENT AND COURSE: As causal treatments are unavailable for McArdle's disease, careful counselling regarding adequate exercise and regular, carbohydrate rich nutrition are mandatory to ameliorate symptoms. CONCLUSION: McArdle's disease represents a rare differential diagnosis of cardiac chest pain and somatoform myalgic complaints. When taking the patient's history, questions regarding the "Second wind"-phenomenon are helpful for initiating the adequate investigations early on.

Dosimetric measurements of (68)Ga-high affinity DOTATATE: twins in spirit - part III.

PURPOSE: 68Ga-labelled compounds are increasingly used for somatostatin-receptor scintigraphy because of their favourable biokinetic properties, a higher tumour-to-background contrast and higher diagnostic accuracy compared to the gamma-emitting tracer 111In-DTPA-octreotide. Recently, we have introduced the new tracer 68Ga-DOTA-3-iodo-Tyr3-Thr8-octreotide (68Ga-HA-DOTATATE). The present study demonstrates the biodistribution and radiation dosimetry of this tracer in humans. PATIENTS, METHODS: Seven men were enrolled in this analysis. Every patient underwent a 20 min dynamic PET scan after intravenous injection of about 114 ± 9 MBq of 68Ga-HA-DOTATATE. This was followed by two whole-body scans at 30 min p. i. and 120 min p. i. Blood radioactivity concentration was determined non-invasively from a ROI drawn over the aorta. Urine was collected until the time of the last scan. Liver, spleen, kidneys and urinary bladder wall were included in the dosimetric estimation that was carried out with the software package OLINDA 1.0. RESULTS: Physiological 68Ga-HA-DOTATATE uptake was observed in the pituitary gland, thyroid, salivary glands, liver, spleen, kidneys, urinary bladder, adrenals and intestine. Organs with the highest absorbed dose were spleen (0.26 ± 0.11 mSv/MBq), kidneys (0.14 ± 0.03 mSv/MBq) and liver (0.12 ± 0.02 mSv/MBq).The estimated effective dose was 0.024 ± 0.001 mSv/MBq. CONCLUSION: Our study demonstrates biokinetics and radiation exposure of the 68Ga-labelled tracer HA-DOTATATE to be comparable to other 68Ga-labelled SSR analogues in clinical use.

[Differential diagnostics of diseases of the brachial plexus]. / Differenzialdiagnose von Erkrankungen des Plexus brachialis.

Progressive, atrophic, asymmetrically distributed flaccid paresis of arm and hand muscles represents a frequent symptom of neuromuscular diseases that can be attributed to injury of the arm nerves, the plexus or the cervical roots. A timely and exact diagnosis is mandatory; however, the broad spectrum of differential diagnoses often represents a diagnostic challenge. A large variety of neuromuscular disorders need to be considered, encompassing autoimmune mediated inflammatory neuropathic conditions, such as multifocal motor neuropathy, as well as chronic degenerative and nerve compression disorders. This review provides an overview of the most frequent disorders of the upper plexus and cervical roots and summarizes the characteristic clinical features as well as electrodiagnostic and laboratory test results. In addition the diagnostic value of magnetic resonance imaging and sonography is discussed.

Sodium-iodide symporter positive cells after intracellular uptake of (99m)Tc versus α-emitter 211At. Reduction of clonogenic survival and characterization of DNA damage.

PURPOSE: We evaluated the DNA damaging potential of Auger electrons emitted in the decay of (99m)Tc compared to α-particles of 211At. MATERIAL AND METHODS: The impact of (99m)Tc and 211At was monitored in a NIS-expressing rat thyroid cell model PCCl3 with varying, yet defined intra- and extracellular radionuclide distribution (using ± perchlorate). The radiotoxicity of (99m)Tc and 211At was studied by the comet assay under neutral and alkaline conditions and colony formation. RESULTS: In the presence of perchlorate, the radioactivity yielding 37% cellular survival, A37, was estimated to be (0.27 ± 0.02) MBq/ml and (450 ± 30) MBq/ml for 211At and (99m)Tc, respectively. In absence of perchlorate, cellular radiotracer uptake was similar for both radionuclides (2.2%, 2.7%), yet the A37 was reduced by 82% for the α-emitter and by 95% for (99m)Tc. Cellular dose increased by a factor of 5 (211At) and 38 (99mTc). Comet assays revealed an increased DNA damage after intracellular uptake of both radiotracers. CONCLUSIONS: The data indicate damage to the cell to occur from absorbed dose without recognizable contribution from intracellular heterogeneity of radionuclide distribution. Comet assay under alkaline and neutral conditions did not reveal any shift to more complex DNA damage after radionuclide uptake. Cellular uptake of (99m)Tc and 211At increased cellular dose and reduced clonogenic survival.

The genetic diversity of Plasmodium malariae and Plasmodium brasilianum from human, simian and mosquito hosts in Brazil.

Plasmodium malariae is a protozoan parasite that causes malaria in humans and is genetically indistinguishable from Plasmodium brasilianum, a parasite infecting New World monkeys in Central and South America. P. malariae has a wide and patchy global distribution in tropical and subtropical regions, being found in South America, Asia, and Africa. However, little is known regarding the genetics of these parasites and the similarity between them could be because until now there are only a very few genomic sequences available from simian Plasmodium species. This study presents the first molecular epidemiological data for P. malariae and P. brasilianum from Brazil obtained from different hosts and uses them to explore the genetic diversity in relation to geographical origin and hosts. By using microsatellite genotyping, we discovered that of the 14 human samples obtained from areas of the Atlantic forest, 5 different multilocus genotypes were recorded, while in a sample from an infected mosquito from the same region a different haplotype was found. We also analyzed the longitudinal change of circulating plasmodial genetic profile in two untreated non-symptomatic patients during a 12-months interval. The circulating genotypes in the two samples from the same patient presented nearly identical multilocus haplotypes (differing by a single locus). The more frequent haplotype persisted for almost 3 years in the human population. The allele Pm09-299 described previously as a genetic marker for South American P. malariae was not found in our samples. Of the 3 non-human primate samples from the Amazon Region, 3 different multilocus genotypes were recorded indicating a greater diversity among isolates of P. brasilianum compared to P. malariae and thus, P. malariae might in fact derive from P. brasilianum as has been proposed in recent studies. Taken together, our data show that based on the microsatellite data there is a relatively restricted polymorphism of P. malariae parasites as opposed to other geographic locations.

The genetic diversity of Plasmodium malariae and Plasmodium brasilianum from human, simian and mosquito hosts in Brazil

Plasmodium malariae is a protozoan parasite that causes malaria in humans and is genetically indistinguish able from Plasmodium brasilianum, a parasite infecting New World monkeys in Central and South America. P. malariae has a wide and patchy global distribution in tropical and subtropical regions, being found in South America, Asia, and Africa. However, little is known regarding the genetics of these parasites and the similarity between them could be because until now there are only a very few genomic sequences available from simian Plasmodium species. This study presents the first molecular epidemiological data for P. malariae and P. brasilianum from Brazil obtained from different hosts and uses them to explore the genetic diversity in relation to geographical origin and hosts. By using microsatellite genotyping, we discovered that of the 14 human samples obtained from areas of the Atlantic forest, 5 different multilocus genotypes were recorded, while in a sample from an infected mosquito from the same region a different haplo type was found. We also analyzed the longitudinal change of circulating plasmodial genetic profile in two untreated non-symptomatic patients during a 12-months interval...

Preincubation with Sn-complexes causes intensive intracellular retention of (99m)Tc in thyroid cells in vitro.

UNLABELLED: Technetium radiopharmaceuticals are well established in nuclear medicine. Besides its well-known gamma radiation, (99m)Tc emits an average of five Auger and internal conversion electrons per decay. The biological toxicity of these low-energy, high-LET (linear energy transfer) emissions is a controversial subject. One aim of this study was to estimate in a cell model how much (99m)Tc can be present in exposed cells and which radiobiological effects could be estimated in (99m)Tc-overloaded cells. METHODS: Sodium iodine symporter (NIS)-positive thyroid cells were used. (99m)Tc-uptake studies were performed after preincubation with a non-radioactive (cold) stannous pyrophosphate kit solution or as a standard (99m)Tc pyrophosphate kit preparation or with pure pertechnetate solution. Survival curves were analyzed from colony-forming assays. RESULTS: Preincubation with stannous complexes causes irreversible intracellular radioactivity retention of (99m)Tc and is followed by further pertechnetate influx to an unexpectedly high (99m)Tc level. The uptake of (99m)Tc pertechnetate in NIS-positive cells can be modified using stannous pyrophosphate from 3-5% to >80%. The maximum possible cellular uptake of (99m)Tc was 90Bq/cell. Compared with nearly pure extracellular irradiation from routine (99m)Tc complexes, cell survival was reduced by 3-4 orders of magnitude after preincubation with stannous pyrophosphate. CONCLUSIONS: Intracellular (99m)Tc retention is related to reduced survival, which is most likely mediated by the emission of low-energy electrons. Our findings show that the described experiments constitute a simple and useful in vitro model for radiobiological investigations in a cell model.

[Ventilation-perfusion-lungscintigraphy using PET and 68Ga-labeled radiopharmaceuticals]. / Ventilations-Perfusions-Lungenszintigraphie mit der PET und 68Ga-markierten Radiopharmaka.

AIM: Imaging of lung perfusion with positron emission tomography (PET) is already possible with 68Ga labeled denaturized albumin. The purpose of our study was to produce and test a 68Ga labeled aerosol (Galligas®) for ventilation and 68Ga labeled albumin particles (microspheres) for perfusion imaging with PET. PATIENTS, METHODS: Galligas was produced by simmering and burning generator eluted 68Ga solution (100 MBq/0.1 ml) in an ordinary technegas generator. Fifteen patients with suspicion on pulmonary embolism underwent PET/CT (Biograph 16) after inhalation of Galligas and application of 68Ga labeled microspheres. A low dose CT was acquired for attenuation correction (AC). Images were reconstructed with and without AC. The inhaled activity was calculated compared to the activity injected. RESULTS: Inhaled radioaerosol Galligas demonstrated typical distribution as known from 99mTc-labeled technegas with homogeneous distribution in lung without hilar deposits. Attenuation corrected images resulted in artefacts in the lung base. Therefore, non-corrected images were used for making the results. Three out of fifteen patients showed a deficient perfusion whereas ventilation was normal corresponding to pulmonary embolism. CONCLUSION: Lung scintigraphy with PET is feasible. Galligas is simple to produce (analogously to technegas). 68Ga labeled microspheres are available. The method is applicable to daily routine and rendered clinically relevant informations.

Continuously increasing sensitivity over three generations of TSH receptor autoantibody assays.

Thyroid stimulating hormone (TSH) receptor (TSHR) antibodies (TRAb) are the hallmarks in serological diagnosis of Graves' disease (GD, autoimmune hyperthyroidism). In the 1980s, the first generation liquid-phase TRAb assay with detergent solubilized porcine TSHR was introduced into routine thyroid serology and proved to be highly specific for GD, albeit with moderate sensitivity. In the 1990 s, second generation solid-phase TRAb assays with immobilized porcine or recombinant human TSHR became available, and were clearly more sensitive for Graves' disease without loss of specificity. Recently, third generation TRAb assays have been developed, in which the human thyroid stimulating monoclonal antibody M22 replaces bovine TSH as the competing reagent for TRAb binding to TSHR. Again, an improvement in functional sensitivity was reported for this latest assay generation. To investigate the analytical (aas) and functional assay sensitivity (fas) over 3 generations of TRAb assays, pooled serum samples from patients with GD were measured 10-fold in different assay lots over a few months. The 20% inter-assay coefficients of variation (CV) were calculated and compared taking into account the different calibrations of the assay generations. The fas continuously increased from about 8 U/l of MRC B65/122 in liquid phase TRAb assays, to about 1.0 IU/l (NIBSC 90/672) in TSH based solid phase TRAb assays and to about 0.3 IU/l (NIBSC 90/672) in the M22 based TRAb assay finally. In conclusion, the fas of TRAb measurements has been improved continuously over the last 3 decades.

[99mTc reduces clonogenic survival after intracellular uptake in NIS-positive cells in vitro more than 131I]. / 99mTc reduziert nach intrazellulärer Aufnahme in NIS-positiven Zellen in vitro das klonogene Uberleben stärker als 131I.

AIM: In addition to gamma radiation of 140 keV 99mTc emits during the transition to 99Tc electrons of low energy and tiny path-lengths. These Auger electrons cannot be utilized in diagnostic procedures. However, they were discussed frequently for therapeutic application. Hitherto proof of effect of the Auger electrons from 99mTc is missing which is supplied now in an in vitro-system in comparison to beta-emitter 131I. METHODS: The thyroid cell line PCCl3 (sodium iodide symporter (NIS)-positive) was incubated with 131I-sodium iodide (131I) or 99mTc-pertechnetate (99mTc) in presence or absence of perchlorate. For comparison the amount of radioactivity was adjusted to obtain the same dose from extracellular irradiation for both radionuclides. The colony forming assay detects the clonogenic cell survival as surviving fraction. In addition, intracellular radionuclide uptake was quantified. RESULTS: Dose effect curves were established for 131I and 99mTc for variable extra- and intracellular distribution of the radioactivity. In presence of perchlorate no cellular uptake of radioactivity was detectable. Survival curves were largely comparable confirming the dosimetric calculations. In absence of perchlorate cellular radiotracer uptake varied from 1.39% (131I) to 1.90% 99mTc). Effects on survival were twice for the beta-emitter and ten-fold higher for 99mTc. CONCLUSIONS: Intracellular uptake of 131I and 99mTc increases DNA-damage compared to strict extracellular radiotracer distribution which was demonstrated by means of colony forming assay. Increasing radiotoxicity from intracellular 99mTc is explained most likely by increased dose deposition in cellular structures due to Auger- and conversion-electrons of low range and high local energy deposition.