Development and characterisation of an irradiation device for biomedical studies covering the solar spectrum with individual regulated spectral bands.

To understand the importance of terrestrial solar exposure on human skin, not only individual spectral components need to be considered in biomedical studies, but also the relevance of the combined action profile of the complete solar spectrum (cSS) must be established. We therefore developed a novel irradiation device that combines the emission of four individual lamps (UVB, UVA, VIS and nIR) to achieve exposure from 280 to 1400 nm with individual controllable lamps. The integrated irradiance of each spectral band is similar to the solar spectrum. The lamps can be utilised individually or in any desired combination. Here we present the design, realisation, and validation of this irradiation device as well as biological results on cellular metabolism (MTT assay), cell cycle alterations, and clonogenic growth in HaCaT cells after exposures to the individual spectral bands as well as their simultaneous combinations. Thereby, we demonstrate that UVB combined with UVA is the main determinant for the metabolic activity within cSS. Also, UVB-dependent effects dominate cell cycle regulation in cSS, whilst UVA and nIR have little influence. Lastly, also clonogenic growth is dominated by the UVB action profile in cSS, despite nIR showing modulatory activity when applied in combination with UVB. Together, this highlights the regulatory influence of the different spectral bands on the three biological endpoints and demonstrates their modulation when being part of the complete solar spectrum.

Cortical thickness across the cingulate gyrus in schizophrenia and its association to illness duration and memory performance.

Schizophrenia has been associated with structural brain abnormalities and cognitive deficits that partly change during the course of illness. In the present study, cortical thickness in five subregions of the cingulate gyrus was assessed in 44 patients with schizophrenia-spectrum disorder and 47 control persons and related to illness duration and memory capacities. In the patients group, cortical thickness was increased in the posterior part of the cingulate gyrus and related to illness duration whereas cortical thickness was decreased in anterior parts unrelated to illness duration. In contrast, cortical thickness was related to episodic and working memory performance only in the anterior but not posterior parts of the cingulate gyrus. Our finding of a posterior cingulate increase may point to either increased parietal communication that is accompanied by augmented neural plasticity or to effects of altered neurodegenerative processes in schizophrenia.

Understanding the relationship between type 2 diabetes and depression: lessons from genetically informative study designs.

AIMS: To conduct a systematic review in order to comprehensively synthesize the findings from a diverse range of genetically informative studies on comorbid depression and type 2 diabetes. METHODS: Database searches (1 January 2008 to 1 June 2020) in PubMed and EMBASE were conducted according to the Preferred Reporting Items for Systematic Reviews and Meta-analyses (PRISMA) guidelines. Eligible reports employed any type of genetically informed design, including twin modelling, Mendelian randomization, genome-wide association studies, polygenetic risk scores, or linkage disequilibrium score regression. Searches generated 451 unique citations, and 16 manuscripts met the inclusion criteria. RESULTS: The included studies addressed three aetiological models of the depression-diabetes relationship: uni- or bi-directional phenotypic causation; shared genetic liability; or gene-environment interaction. From these studies, there is modest evidence that type 2 diabetes is causally related to risk of developing depression, but much more limited evidence that depression is causally related to risk of diabetes. There is little evidence of shared genetic liability between depression and diabetes or of gene-environment interaction. CONCLUSIONS: Findings from genetically informed studies are mixed but provide some support for the uni- or bi-directional phenotypic model of depression and type 2 diabetes. Future studies should also explore the hypothesis that this relationship may be influenced by shared environmental risk factors. Findings can inform multifaceted approaches to diabetes prevention and care that reflect how psychosocial factors contribute to type 2 diabetes risk and outcomes.

Systemic mesenchymal stem cell administration enhances bone formation in fracture repair but not load-induced bone formation.

Mesenchymal stem cells (MSC) were shown to support bone regeneration, when they were locally transplanted into poorly healing fractures. The benefit of systemic MSC transplantation is currently less evident. There is consensus that systemically applied MSC are recruited to the site of injury, but it is debated whether they actually support bone formation. Furthermore, the question arises as to whether circulating MSC are recruited only in case of injury or whether they also participate in mechanically induced bone formation. To answer these questions we injected green fluorescent protein (GFP)-labelled MSC into C57BL/6J mice, which were subjected either to a femur osteotomy or to non-invasive mechanical ulna loading to induce bone formation. We detected GFP-labelled MSC in the early (day 10) and late fracture callus (day 21) by immunohistochemistry. Stromal cell-derived factor 1 (SDF-1 or CXCL-12), a key chemokine for stem cell attraction, was strongly expressed by virtually all cells near the osteotomy--indicating that SDF-1 may mediate cell migration to the site of injury. We found no differences in SDF-1 expression between the groups. Micro-computed tomography (µCT) revealed significantly more bone in the callus of the MSC treated mice compared to untreated controls. The bending stiffness of callus was not significantly altered after MSC-application. In contrast, we failed to detect GFP-labelled MSC in the ulna after non-invasive mechanical loading. Histomorphometry and µCT revealed a significant load-induced increase in bone formation; however, no further increase was found after MSC administration. Concluding, our results suggest that systemically administered MSC are recruited and support bone formation only in case of injury but not in mechanically induced bone formation.

Attenuated prefrontal activation during decision-making under uncertainty in schizophrenia: a multi-center fMRI study.

Decisions are called decisions under uncertainty when either prior information is incomplete or the outcomes of the decision are unclear. Alterations in these processes related to decisions under uncertainty have been linked to delusions. In patients with schizophrenia, the underlying neural networks have only rarely been studied. We aimed to disentangle the neural correlates of decision-making and relate them to neuropsychological and psychopathological parameters in a large sample of patients with schizophrenia and healthy subjects. Fifty-seven patients and fifty-seven healthy volunteers from six centers had to either indicate via button-press from which of two bottles red or blue balls were drawn (decision-making under uncertainty condition), or indicate whether eight red balls had been presented (baseline condition) while BOLD signal was measured with fMRI. Patients based their decisions on less conclusive evidence and had decreased activations in the underlying neural network, comprising of medial and lateral frontal as well as parietal areas, as compared to healthy subjects. While current psychopathology was not correlated with brain activation, positive symptoms led to longer decision latencies in patients. These results suggest that decision-making under uncertainty in schizophrenia is affected by a complex interplay of aberrant neural activation. Furthermore, reduced neuropsychological functioning in patients was related to impaired decision-making and task performance was modulated by distinct positive symptoms.

Investigation of decision-making under uncertainty in healthy subjects: a multi-centric fMRI study.

Decision-making is an everyday routine that entails several subprocesses. Decisions under uncertainty occur when either prior information is incomplete or the outcomes of the decision are unclear. The aim of the present study was to disentangle the neural correlates of information gathering as well as reaching a decision and to explore effects of uncertainty acceptance or avoidance in a large sample of healthy subjects. Sixty-four healthy volunteers performed a decision-making under uncertainty task in a multi-center approach while BOLD signal was measured with fMRI. Subjects either had to indicate via button press from which of two bottles red or blue balls were drawn (decision-making under uncertainty condition), or they had to indicate whether 8 red balls had been presented (baseline condition). During the information gathering phase (contrasted against the counting phase) a widespread network was found encompassing (pre-)frontal, inferior temporal and inferior parietal cortices. Reaching a decision was correlated with activations in the medial frontal cortex as well as the posterior cingulate and the precuneus. Effects of uncertainty acceptance were found within a network comprising of the superior frontal cortex as well as the insula and precuneus while uncertainty avoidance was correlated with activations in the right middle frontal cortex. The results depict two distinct networks for information gathering and the indication of having made a decision. While information-gathering networks are modulated by uncertainty avoidance and - acceptance, underlying networks of the decision itself are independent of these factors.

Neural correlates of irony comprehension: the role of schizotypal personality traits.

To detect that a conversational turn is intended to be ironic is a difficult challenge in everyday language comprehension. Most authors suggested a theory of mind deficit is crucial for irony comprehension deficits in psychiatric disorders like schizophrenia; however, the underlying pathophysiology and neurobiology are unknown and recent research highlights the possible role of language comprehension abnormalities. Fifteen female right-handed subjects completed personality testing as well as functional magnetic resonance imaging (fMRI) and neuropsychology. Subjects were recruited from the general population. No subject had a lifetime history of relevant psychiatric disorder; however, subjects differed in their score on the German version of the schizotypal personality questionnaire (SPQ). During fMRI scans, the subjects silently read 44 short text vignettes that ended in either an ironic or a literal statement. Imaging was performed using a 3 T Siemens scanner. The influence of schizotypy on brain activation was investigated by using an SPM5 regression analysis with the SPQ total score and the SPQ cognitive-perceptual score as regressors. Reading ironic in contrast to literal sentences activated a bilateral network including left medial prefrontal and left inferior parietal gyri. During reading of ironic sentences, brain activation in the middle temporal gyrus of both hemispheres showed a significant negative association with the SPQ total score and the SPQ cognitive-perceptual score. Significant positive correlation with the SPQ total score was present in the left inferior frontal gyrus. We conclude schizotypal personality traits are associated with a dysfunctional lateral temporal language rather than a theory of mind network.

UVA radiation causes DNA strand breaks, chromosomal aberrations and tumorigenic transformation in HaCaT skin keratinocytes.

The role of UVA-radiation-the major fraction in sunlight-in human skin carcinogenesis is still elusive. We here report that different UVA exposure regime (4 x 5 J/cm(2) per week or 1 x 20 J/cm(2) per week) caused tumorigenic conversion (tumors in nude mice) of the HaCaT skin keratinocytes. While tumorigenicity was not associated with general telomere shortening, we found new chromosomal changes characteristic for each recultivated tumor. Since this suggested a nontelomere-dependent relationship between UVA irradiation and chromosomal aberrations, we investigated for alternate mechanisms of UVA-dependent genomic instability. Using the alkaline and neutral comet assay as well as gamma-H2AX foci formation on irradiated HaCaT cells (20-60 J/cm(2)), we show a dose-dependent and long lasting induction of DNA single and double (ds) strand breaks. Extending this to normal human skin keratinocytes, we demonstrate a comparable damage response and, additionally, a significant induction and maintenance of micronuclei (MN) with more acentric fragments (indicative of ds breaks) than entire chromosomes particularly 5 days post irradiation. Thus, physiologically relevant UVA doses cause long-lasting DNA strand breaks, a prerequisite for chromosomal aberration that most likely contribute to tumorigenic conversion of the HaCaT cells. Since normal keratinocytes responded similarly, UVA may likewise contribute to the complex karyotype characteristic for human skin carcinomas.

Expression levels of 63 p53-related genes add up to similar values in 24 different tissues and are unified in cancer.

The expression patterns of 62 genes interacting with p53 have been investigated in 24 normal and cancerous tissues using NIH's dbEST library. The expression levels of individual genes, such as the TTP53 gene itself, but also other genes, vary up to 33-fold among the 24 different tissues and no consistent pattern can be recognized. However, when expression levels for all 63 genes are summed, these "cumulated levels" are surprisingly constant over the 24 investigated normal tissues. In cancers, the variation is further reduced. Essentially, the cumulated expression levels in cancer are independent of those in normal tissue. We furthermore constructed a linear statistical classifier, i.e., a weighted sum of gene expression levels, which robustly distinguishes normal from cancer tissue independent of the particular kind of tissue. Thus, despite very large differences for individual genes and considerable changes during carcinogenesis, the cumulated expressions have narrowly defined levels.

Humor and smiling: cortical regions selective for cognitive, affective, and volitional components.

BACKGROUND: The interrelationships among humor, smiling, and grinning have fascinated philosophers for millennia and neurologists for over a century. A functional dissociation between emotional facial expressions and those under voluntary control was suggested decades ago. Recent functional imaging studies, however, have been somewhat at odds with older studies with respect to the role of the right frontal cortex in the perception of humor. METHODS: Blood oxygen level-dependent (BOLD) activity was measured in 13 subjects during the presentation of "funny" vs "nonfunny" versions of essentially the same cartoons and compared with BOLD activity associated with "merely grinning" at similar nonfunny cartoons via fMRI. RESULTS: Humor perception was correlated with BOLD activity in the left temporo-occipitoparietal junction and left prefrontal cortex and humor-associated smiling (recorded with an MR-compatible video camera) with bilateral activity in the basal temporal lobes. Unexpectedly, both conditions were also accompanied by a decrease in BOLD activity in the right orbitofrontal cortex. Voluntary "grinning" in the absence of humorous stimuli was accompanied by bilateral activity in the facial motor regions. CONCLUSIONS: These results confirm the clinically derived hypothesis of separate cortical regions responsible for the production of emotionally driven vs voluntary facial expressions. The right orbitofrontal decrease reconciles inconsistencies between clinical and functional imaging findings and may reflect a disinhibition of facial emotional expression.

UVA-induced apoptosis studied by the new apo/necro-Comet-assay which distinguishes viable, apoptotic and necrotic cells.

An adaptation of the Comet-assay was developed which enables the discrimination of viable, apoptotic and necrotic single cells by use of the common Annexin-V staining and a dye exclusion test on the cells already embedded in agarose gel on glass slides. Membrane integrity (Ethidium-Homodimer exclusion), cellular esterase activity (Calcein blue-AM) as well as translocation of phosphadidyl-serine (Annexin-V) were analysed using these stains. The advantage of the 'apo/necro-Comet-assay' is that the viability status of individual cells can be determined and correlated with the DNA fragmentation pattern (comet) formed by the same cells. Hence, DNA damage can be assessed and correlated with viable cells or cells undergoing early, mid- or late stage apoptosis or necrosis as identified by the staining pattern. The staining was verified using heat and etoposide-induced apoptosis. This technique, among others, was used to study whether apoptotic fragmentation interferes with repair kinetics measured with the comet assay following UVA exposure (doses up to 1,280 kJ/m(2)) in the cultured human keratinocytes (HaCaT). Therefore, a time course of apoptotic events (phosphatidyl translocation and TUNEL fragmentation) was established and correlated to the DNA fragmentation in the comet-assay. Apoptotic cells were detected more than 8 h later. The combined three-colour staining method with the comet assay showed that there was no significant interference of DNA repair by apoptotic fragmentation processes since DNA repair was almost completed before the onset of apoptotic fragmentation. The apo/necro-Comet-assay reduces the general problem of false-positive results in genotoxicity tests using the Comet-assay.

Comet-assay in combination with PNA-FISH detects mutagen-induced DNA damage and specific repeat sequences in the damaged DNA of transformed cells.

The Comet-assay was applied to three transformed cell lines (HT1080, CCRF-CEM line and CHO) which were treated with the cytostatics bleomycin (BLM) or mitomycin C (MMC). In addition, PNA probes for the telomere repeat (TTAGGG)(n) were used for detection of telomeric DNA sequences in the damaged DNA. Data were compared with previously obtained results from peripheral leukocytes. The amount of migrating DNA increased in all cell types in a dose-dependent manner after BLM exposure. CHO cells reacted sensitively at low doses of the mutagen, and leukocytes had the highest dose-related effect up to 25 IU/ml which, however, did not further increase. A rather linear dose response characterized the HT1080 cells, the effect was lowest for the CCRF-CEM cells. While MMC at lower doses increased the percentage of migrating DNA in a dose-dependent manner, the higher doses induced shorter comets, on average, than the lower ones in all cell lines. With PNA-Comet-FISH obvious differences were found between the studied cell lines with respect to quantitative head/tail distribution of telomeric signals after BLM exposure. A large number of signal spots of various sizes were found in CHO cells, very small signals could be detected in the comets of both neoplasia cell lines. Dose-dependence of telomeres in the tail was most pro-nounced in CCRF-CEM and normal leukocytes, less in HT1080. The steepest dose-related increase of telomeric signals in the tail was found in CHO cells. The ratio between the migrated DNA and the telomeric signals in the tail varied distinctly between the examined cell types from 3:1 to 1:1. Taken together, Comet-FISH can detect mutagenic effects on specific DNA sequences. This may be of high practical value if amplified DNA sequences will be addressed by those examinations in future.

Putative colon cancer risk factors damage global DNA and TP53 in primary human colon cells isolated from surgical samples.

This study describes a novel in vitro method in genetic toxicology that is based on detection of chemical-induced DNA damage connected with altered migration of TP53 in primary human colonocytes. Techniques were developed to isolate high numbers of human epithelial colon cells from surgical tissues. High quantities of viable cells were obtained per donor. The primary cells were treated with the endogenous risk factors trans-2-hexenal, and hydrogen peroxide. Global DNA damage and repair were measured by single-cell gel electrophoresis (Comet assay). We compared responses of primary colon cells to HT29clone19A, a differentiated human colon tumour cell line, for which the karyotype was analysed with 24-colour FISH. Both compounds were genotoxic in both cell types and most of the induced DNA damage was repaired after 30 min. Specific migration of TP53 was determined by fluorescence in situ hybridization (Comet FISH). Using primary colon cells, we quantified the migration of TP53 signals into the comet tails. In these cells TP53 was more sensitive than global DNA for genotoxicity induced by trans-2-hexenal and H(2)O(2). HT29clone19A cells cannot be used for Comet FISH because of their aberrant karyotype. The approach described allows us to obtain more knowledge of putative risk factors in colon carcinogenesis.

Labelling quality and chromosome morphology after low temperature FISH analysed by scanning far-field and near-field optical microscopy.

A non-enzymatic, low temperature fluorescence in situ hybridization (LTFISH) procedure was applied to metaphase spreads and interphase cell nuclei. In this context 'low temperature' means that the denaturation procedure of the chromosomal target DNA usually applied by heat treatment and chaotropic agents such as formamide was completely omitted so that the complete hybridization reaction took place at 37 degrees C. For LTFISH, the DNA probe had to be single-stranded, which was achieved by means of separate thermal denaturation of the DNA probe only. The DNA probe pUC1.77 was used for all LTFISH experiments. The labelling quality (number of binding sites, relative background intensity, relative intensity of major and minor binding sites) was analysed by confocal laser scanning microscopy (CLSM). An optimum in specificity and signal quality was obtained for 15 h hybridization time. For this hybridization condition of LTFISH, the chromosomal morphology was analysed by scanning near-field optical microscopy (SNOM). The results were compared with the morphology of chromosomes after (a) labelling of all centromeres using the same chemical treatment in the FISH procedure but with the application of target denaturation, and (b) labelling of all centromeres using a standard FISH protocol including thermal denaturation of the DNA probe and the chromosomal target. Depending on the FISH-procedure applied, SNOM images show substantial differences in the chromosome morphology. After LTFISH the chromosome morphology appeared to be much better preserved than after standard FISH. In contrast, the application of the LTFISH chemical treatment accompanied by heat denaturation had a very destructive influence on chromosomal morphology. The results indicate that, at least for certain DNA probes, specific chromosome labelling can be obtained without the usually applied heat and chemical denaturation of the DNA target, resulting in an apparently well preserved chromatin morphology as visualized by SNOM. LTFISH may be therefore a useful labelling technique whenever the chromosomal morphology had to be preserved after specific labelling of DNA regions. Binding mechanisms of single-stranded DNA probes to double-stranded DNA targets are discussed.

Variations in cell surfaces of estrogen treated breast cancer cells detected by a combined instrument for far-field and near-field microscopy.

The response of single breast cancer cells (cell line T-47D) to 17beta-estradiol (E(2)) under different concentrations was studied by using an instrument that allows to combine far-field light microscopy with high resolution scanning near-field (AFM/SNOM) microscopy on the same cell. Different concentrations of E(2) induce clearly different effects as well on cellular shape (in classical bright-field imaging) as on surface topography (atomic force imaging) and absorbance (near-field light transmission imaging). The differences range from a polygonal shape at zero via a roughly spherical shape at physiological up to a spindle-like shape at un-physiologically high concentrations. The surface topography of untreated control cells was found to be regular and smooth with small overall height modulations. At physiological E(2) concentrations the surfaces became increasingly jagged as detected by an increase in membrane height. After application of the un-physiological high E(2) concentration the cell surface structures appeared to be smoother again with an irregular fine structure. The general behaviour of dose dependent differences was also found in the near-field light transmission images. In order to quantify the treatment effects, line scans through the normalised topography images were drawn and a rate of co-localisation between high topography and high transmission areas was calculated. The cell biological aspects of these observations are, so far, not studied in detail but measurements on single cells offer new perspectives to be empirically used in diagnosis and therapy control of breast cancers.

Self-organization of supramolecular helical dendrimers into complex electronic materials.

The discovery of electrically conducting organic crystals and polymers has widened the range of potential optoelectronic materials, provided these exhibit sufficiently high charge carrier mobilities and are easy to make and process. Organic single crystals have high charge carrier mobilities but are usually impractical, whereas polymers have good processability but low mobilities. Liquid crystals exhibit mobilities approaching those of single crystals and are suitable for applications, but demanding fabrication and processing methods limit their use. Here we show that the self-assembly of fluorinated tapered dendrons can drive the formation of supramolecular liquid crystals with promising optoelectronic properties from a wide range of organic materials. We find that attaching conducting organic donor or acceptor groups to the apex of the dendrons leads to supramolecular nanometre-scale columns that contain in their cores pi-stacks of donors, acceptors or donor-acceptor complexes exhibiting high charge carrier mobilities. When we use functionalized dendrons and amorphous polymers carrying compatible side groups, these co-assemble so that the polymer is incorporated in the centre of the columns through donor-acceptor interactions and exhibits enhanced charge carrier mobilities. We anticipate that this simple and versatile strategy for producing conductive pi-stacks of aromatic groups, surrounded by helical dendrons, will lead to a new class of supramolecular materials suitable for electronic and optoelectronic applications.

Comet assay measurements of DNA damage in cells by laser microbeams and trapping beams with wavelengths spanning a range of 308 nm to 1064 nm.

DNA damage induced in NC37 lymphoblasts by optical tweezers with a continuous-wave Ti:sapphire laser and a continuous-wave Nd:YAG laser (60-240 mW; 10-50 TJ/m2; 30-120 s irradiation) was studied with the comet assay, a single-cell technique used to detect DNA fragmentation in genomes. Over the wavelength range of 750-1064 nm, the amount of damage in DNA peaks at around 760 nm, with the fraction of DNA damage within the range of 750-780 nm being a factor of two larger than the fraction of DNA damage within the range of 800-1064 nm. The variation in DNA damage was not significant over the range of 800-1064 nm. When the logarithm of damage thresholds measured in the present work, as well as values reported previously in the UV range, was plotted as a function of wavelength, a dramatic wavelength dependence became apparent. The damage threshold values can be fitted on two straight lines, one for continuous-wave sources and the other for pulsed sources, irrespective of the type of source used (e.g. classical lamp or laser). The damage threshold around 760 nm falls on the line extrapolated from values for UV-radiation-induced damage, while the data for 800-1064 nm fall on a line that has a different slope. The change in the slope between 320 and 340 nm observed earlier is consistent with a well-known change in DNA-damaging mechanisms. The change observed around 780 nm is therefore suggestive of a further change in the mechanism(s). The data from this work together with our previous measurements provide, to the best of our knowledge, the most comprehensive view available of the DNA damage produced by microfocused light.