[Acute mental health-caregivers speaking about Meaning in Life when assessing suicidality: a qualitative study]. / Zingeving en suïcidaliteit volgens crisisdiensthulpverleners: een kwalitatief onderzoek.

BACKGROUND: The Multidisciplinary guideline for diagnostics and treatment of suicidal behaviour recommends paying attention to the patients’ perception of meaning in life (MiL) while examining their suicidality. It is unknown how caregivers do this in practice. AIM: To gain insight into the way and the extent in which clinicians explore MiL with patients being assessed for
suicidality and their experiences with it. METHOD: Qualitative research with in-depth interviews among eleven caregivers in acute mental health of Altrecht: data were thematically analysed both deductively and inductively. RESULTS: Five themes emerged: how aspects of MiL emerge in the conversation about suicidality; the intention to understand suicidality by exploring possible protective factors; the effect on patients; the helping and impeding factors for discussing MiL; the participant’s attitude of being present while speaking about the patient’s MiL. CONCLUSION: Participants experience the conversation about MiL with suicidal patients as relevant. It provides information about protective factors, which contributes to the understanding of suicidality. The concept of MiL requires further operationalisation. Follow-up research into the several aspects of MiL in relation to diagnostics of suicidality is recommended.

First Experimental Characterization of Microwave Emission from Cosmic Ray Air Showers.

We report the first direct measurement of the overall characteristics of microwave radio emission from extensive air showers. Using a trigger provided by the KASCADE-Grande air shower array, the signals of the microwave antennas of the Cosmic-Ray Observation via Microwave Emission experiment have been read out and searched for signatures of radio emission by high-energy air showers in the GHz frequency range. Microwave signals have been detected for more than 30 showers with energies above 3×10^{16} eV. The observations presented in this Letter are consistent with a mainly forward-directed and polarized emission process in the GHz frequency range. The measurements show that microwave radiation offers a new means of studying air showers at E≥10^{17} eV.

UV-induced ablation of the epidermal basal layer including p53-mutant clones resets UV carcinogenesis showing squamous cell carcinomas to originate from interfollicular epidermis.

Chronic ultraviolet (UV) exposure induces clones of cells overexpressing mutant p53 in the interfollicular (IF) epidermis and subsequently squamous cell carcinomas (SCCs) with similar p53 mutations. Mutated p53 may give cells growth advantage over neighbouring cells by impaired apoptosis. We tested this by UV overexposure of skin laden with p53-mutant clones and assessed the impact on subsequent tumour development. P53-mutant clones were induced in two groups of hairless SKH1 mice by daily exposures (500 J/m(2) UV from TL12 lamps) for 28 days. On day 29, one group was overexposed (to 10 kJ/m(2) UV), whereas the control group received the regular daily dose. After 1 week of recovery, the daily exposures were resumed in both groups to induce SCCs. UV overexposure forced the entire IF basal layer into caspase-3-driven apoptosis while leaving overlying layers with sunburn cells intact. No apparent regions were spared from apoptosis. Pulse-chase BrdU labelling showed the IF epidermis to be repopulated from the hair follicles (remaining p63 positive). One week after overexposure, the p53-mutant clones had virtually disappeared (0.6, 95% confidence interval 0.5-0.8 per mouse versus 102, 59-179, without overexposure). Tumour development was significantly delayed after UV overexposure (P < 0.0001) by an average of 27 days (standard error of the mean 3); a period matching that of daily exposures preceding the overexposure. Thus, we found that UV-induced ablation of the IF epidermal basal layer eliminates p53-mutant clones and resets UV carcinogenesis. Furthermore, and in contrast with earlier reports, our data show that UV-induced p53-mutant clones and SCCs originate from the IF epidermis.

Rapamycin impairs UV induction of mutant-p53 overexpressing cell clusters without affecting tumor onset.

Because of its antitumor effect, the immunosuppressant rapamycin holds great promise for organ transplant recipients in that it may lower their cancer risk. In a mouse model, we showed previously that rapamycin inhibits the outgrowth of primary skin carcinomas induced by UV radiation. However, the tumors that did grow out showed an altered p53 mutation spectrum. Here, we investigated whether this shift in p53 mutations already occurred in the smallest tumors, which were not affected in onset. We found that rapamycin did not alter the mutational spectrum in small tumors and in preceding microscopic clusters of cells expressing mutant-p53. However, rapamycin did reduce the number of these cell clusters. As this reduction did not affect tumor onset, we subsequently investigated whether rapamycin merely suppressed expression of mutated p53. This was not the case, as we could demonstrate that switching from a diet with rapamycin to one without, or vice versa, did not affect the number of existing mutant-p53 expressing cell clusters. Hence, rapamycin actually reduced the formation of mutant-p53 cell clusters. In wild-type and p53-mutant mice, we could not measure a significant enhancement of UV-induced apoptosis, but we did observe clear enhancement in human skin equivalents. This was associated with a clear suppression of HIF1α accumulation. Thus, we conclude that rapamycin reduces the formation of mutant-p53-expressing cell clusters without affecting tumor onset, suggesting that tumors grow out of a minor subset of cell clusters, the formation of which is not affected by rapamycin.

Kneelike structure in the spectrum of the heavy component of cosmic rays observed with KASCADE-Grande.

We report the observation of a steepening in the cosmic ray energy spectrum of heavy primary particles at about 8×10(16) eV. This structure is also seen in the all-particle energy spectrum, but is less significant. Whereas the "knee" of the cosmic ray spectrum at 3-5×10(15) eV was assigned to light primary masses by the KASCADE experiment, the new structure found by the KASCADE-Grande experiment is caused by heavy primaries. The result is obtained by independent measurements of the charged particle and muon components of the secondary particles of extensive air showers in the primary energy range of 10(16) to 10(18) eV. The data are analyzed on a single-event basis taking into account also the correlation of the two observables.

Early and late effects of the immunosuppressants rapamycin and mycophenolate mofetil on UV carcinogenesis.

Increased skin cancer risk in organ transplant recipients has been experimentally emulated with enhanced UV carcinogenesis from administering conventional immunosuppressants. However, newer generation immunosuppressive drugs, rapamycin (Rapa) and mycophenolate mofetil (MMF), have been shown to impair angiogenesis and outgrowth of tumor implants. To ascertain the overall effect on UV carcinogenesis, Rapa and MMF were admixed into the food pellets of hairless SKH1 mice receiving daily sub-sunburn UV dosages. With immunosuppressive blood levels neither of the drugs affected onset of tumors (<2 mm), but in contrast to MMF, Rapa significantly increased latency of large tumors (>or=4 mm, medians of 190 vs 125 days) and reduced their multiplicity (1.6 vs 4.5 tumors per mouse at 200 days). Interestingly, tumors (>2 mm) from the Rapa-fed group showed a reduction in UV-signature p53 mutations (39% vs 90%) in favor of mutations from putative base oxidation. This shift in mutation spectrum was not essentially linked to the reduction in large tumors because it was absent in large tumors similarly reduced in number when feeding Rapa in combination with MMF, possibly owing to an antioxidant effect of MMF. Significantly fewer tumor cells were Vegf-positive in the Rapa-fed groups, but a correspondingly reduced expression of Hif1alpha target genes (Vegf, Ldha, Glut1, Pdk1) that would indicate altered glucose metabolism with increased oxidative stress was not found. Remarkably, we observed no effect of the immunosuppressants on UV-induced tumor onset, and with impaired tumor outgrowth Rapa could therefore strongly reduce skin carcinoma morbidity and mortality rates in organ transplant recipients.

Early p53-positive foci as indicators of tumor risk in ultraviolet-exposed hairless mice: kinetics of induction, effects of DNA repair deficiency, and p53 heterozygosity.

p53 mutations appear to be early events in skin carcinogenesis induced by chronic UVB irradiation. Clusters of epidermal cells that express p53 in mutant conformation ("p53 positive foci") are easily detected by immunohistochemical staining long before the appearance of skin carcinomas or their precursor lesions. In a hairless mouse model, we determined the dose-time dependency of the induction of these p53+ foci and investigated the relationship with the induction of skin carcinomas. The density of p53+ foci may be a good direct indicator of tumor risk. Hairless SKH1 mice were exposed to either of two regimens of daily UVB (500 or 250 J/m2 broadband UV from Philips TL12 lamps; 54% UVB 280-315 nm). With the high-dose regimen, the average number of p53+ foci in a dorsal skin area (7.2 cm2) increased rapidly from 9.0 +/- 2.1 (SE) at 15 days to 470 +/- 80 (SE) at 40 days. At half that daily dose, the induction of p53+ foci was slower by a factor of 1.49 +/- 0.15, very similar to a previously observed slower induction of squamous cell carcinomas by a factor of 1.54 +/- 0.02. In a double-log plot of the average number of p53 + foci versus time, the curves for the two exposure regimens ran parallel (slope, 3.7 +/- 0.7), similar to the curves for the number of tumors versus time (slope, 6.9 +/- 0.8). The difference in slopes (3.7 versus 6.9) is in line with the contention that more rate-limiting steps are needed to develop a tumor than a p53+ focus. By the time the first tumors appear (around 7-8 weeks with the high daily dose), the dorsal skin contains >100 p53+ foci/cm2. To further validate the density of p53+ foci as a direct measure of tumor risk, we carried out experiments with transgenic mice with an enhanced susceptibility to UV carcinogenesis, homozygous Xpa knockout mice (deficient in nucleotide excision repair) and heterozygousp53 knockout mice (i.a. partially deficient in apoptosis). In both of these cancer-prone strains, the p53+ foci were induced at markedly increased rates, corresponding to increased rates of carcinoma formation. Therefore, the frequency of p53+ foci appears to correlate well with UVB-induced tumor risk.

Differential role of transcription-coupled repair in UVB-induced G2 arrest and apoptosis in mouse epidermis.

Nucleotide excision repair (NER), apoptosis, and cell-cycle regulation are major defense mechanisms against the carcinogenic effects of UVB light. NER eliminates UVB-induced DNA photolesions via two subpathways: global genome repair (GGR) and transcription-coupled repair (TCR). Defects in NER result in the human disorders xeroderma pigmentosum (XP) and Cockayne syndrome (CS), displaying severe UV sensitivity and in the case of XP, cancer proneness. We investigated the impact of deficiencies in NER subpathways on apoptosis, hyperplasia, and cell cycle progression in the epidermis of UVB-exposed CS group B (Csb(-/-)) mice (no TCR), XP group C (Xpc(-/-)) mice (no GGR), and XP group A (Xpa(-/-)) mice (no TCR and no GGR). On UVB treatment (250 J/m(2)), Xpa(-/-) and Csb(-/-) mice revealed an extensive apoptotic response in the skin, a blockage of cell cycle progression of epidermal cells, and strong hyperplasia. Interestingly, the absence of this apoptotic response in the skin of wild-type and Xpc(-/-) mice coincided with the ability of epidermal cells to enter the S phase. However, only epidermal cells of Xpc(-/-) mice subsequently became arrested in the G(2) phase. Our data demonstrate that TCR (and/or restoration of UVB-inhibited transcription) enables damaged cells to progress through S phase and prevents the induction of apoptosis and hyperplasia. G(2) arrest is manifest only under conditions of proficient TCR in combination with deficient GGR, indicating that epidermal cells become arrested in the G(2) phase as a result of persisting damage in their genome.

Impact of global genome repair versus transcription-coupled repair on ultraviolet carcinogenesis in hairless mice.

The nucleotide excision repair (NER) system is comprised of two subpathways, i.e., transcription-coupled repair (TCR) and global genome repair (GGR). To establish the relative importance of TCR and GGR for UV effects on the skin, we have used hairless knockout mouse strain lacking either TCR (CSB -/-) or GGR (XPC -/-). In single exposure experiments, we found that CSB -/- mice have a 7-16 times higher susceptibility to sunburn than XPC -/- mice and than heterozygous (+/-) and wild-type (+/+) controls. Exposure to 80 J/m2 UV radiation (i.e., suberythemogenic in CSB -/-) on 10 consecutive days gives rise to epidermal hyperplasia in CSB -/- and XPC -/-, whereas repair-proficient controls do not show epidermal hyperplasia from these exposures. In addition, CSB -/- mice develop marked parakeratosis, whereas XPC -/- mice and controls do not. Under continued exposure to this daily dose, squamous cell carcinomas appear in CSB -/-, XPC -/-, and in the control groups, whereas only in the CSB -/- animals is a fairly high number of benign papillomas also found. The median latency time of squamous cell carcinomas (diameters > or = 1 mm) is 84 days for the XPC -/- mice, 115 days for the CSB -/- mice, and 234-238 days for the heterozygous and wild-type control groups. These results indicate that GGR is more important than TCR in protection against UV-induced carcinomas of the skin but not against other UV effects such as sunburn, epidermal thickening, scaling of the stratum corneum, and development of papillomas. These results also indicate that GGR capacity may serve as a better predictor for skin cancer susceptibility than sensitivity to sunburn. The relative cancer susceptibilities of GGR- and TCR-deficient skin could well depend on the balance between an increased mutation rate and the presence (in CSB -/-) or lack (in XPC -/-) of a compensatory apoptotic response.

UVB-induced mutagenesis in hairless lambda lacZ-transgenic mice.

UVB-induced mutagenesis was studied in hairless 40.6 transgenic mice (MutaMouse), which contain the lambda gt10lacZ shuttle vector as a target for mutagenesis. Mice were exposed at the dorsal side to either single doses of 200, 500, 800, or 1000 J/m2 UVB or to two successive irradiations of either 200 and 800 J/m2 UVB, with intervals of 1, 3, or 5 days, or to 800 and 200 J/m2 UVB with a 5-day interval. At 23 days after the last exposure, lacZ mutant frequencies (MF) were determined in the epidermis. The lacZ MF increased linearly with increasing dose of UVB. The mutagenic effect of two successive irradiations appeared to be additive. The UV-induced mutation spectrum was dominated by G:C --> A:T transitions at dipyrimidine sites. DNA-sequence analysis of spontaneously mutated phages showed a diverse spectrum consisting of insertions, deletions and G:C --> A:T transitions at CpG sites. The results indicate that the hairless lambda lacZ-transgenic mouse is a suitable in vivo model for studying UVB-induced mutations.

Early p53 alterations in mouse skin carcinogenesis by UVB radiation: immunohistochemical detection of mutant p53 protein in clusters of preneoplastic epidermal cells.

High levels of the p53 protein are immunohistochemically detectable in a majority of human nonmelanoma skin cancers and UVB-induced murine skin tumors. These increased protein levels are often associated with mutations in the conserved domains of the p53 gene. To investigate the timing of the p53 alterations in the process of UVB carcinogenesis, we used a well defined murine model (SKH:HR1 hairless mice) in which the time that tumors appear is predictable from the UVB exposures. The mice were subjected to a series of daily UVB exposures, either for 17 days or for 30 days, which would cause skin tumors to appear around 80 or 30 weeks, respectively. In the epidermis of these mice, we detected clusters of cells showing a strong immunostaining of the p53 protein, as measured with the CM-5 polyclonal antiserum. This cannot be explained by transient accumulation of the normal p53 protein as a physiological response to UVB-induced DNA damage. In single exposure experiments the observed transient CM-5 immunoreactivity lasted for only 3 days and was not clustered, whereas these clusters were still detectable as long as 56 days after 17 days of UVB exposure. In addition, approximately 70% of these patches reacted with the mutant-specific monoclonal antibody PAb240, whereas transiently induced p53-positive cells did not. In line with indicative human data, these experimental results in the hairless mouse model unambiguously demonstrate that constitutive p53 alterations are causally related to chronic UVB exposure and that they are a very early event in the induction of skin cancer by UVB radiation.

Isolation and characterization of permanent cell lines from inner cell mass cells of bovine blastocysts.

Inner cell masses (ICM) from in vitro produced day 8 or 9 bovine blastocysts were isolated by immunosurgery and cultured under different conditions in order to establish which of two feeder cell types and culture media were most efficient in supporting attachment and outgrowth of the bovine ICM cells. The efficiency of attachment and outgrowth of the ICM cells could be markedly improved when STO feeder cells were used instead of bovine uterus epithelial cells, and by using charcoal-stripped serum instead of normal serum to supplement the culture medium. More than 20 stable cell lines were obtained. Some of these lines were examined by immunofluorescence for developmentally regulated markers. From these results we conclude that the cell lines resemble epithelial cells, rather than pluripotent ICM cells. The developmental potential of cells of one of the lines was tested in the nuclear transfer assay. The cell line could support the initial development of enucleated oocytes, but none of the reconstructed embryos passed the eight-cell block.

Stage-specific appearance of the mouse antigen TEC-3 in normal and nuclear transfer bovine embryos: re-expression after nuclear transfer.

Bovine embryos, recovered from the uterus in vivo or derived from in vitro matured and in vitro fertilized oocytes, were investigated for the presence of the developmentally regulated mouse antigen TEC-3 by indirect immunofluorescence. During preimplantation embryo development TEC-3 is expressed on bovine morulae and blastocysts. It is absent from unfertilized and fertilized oocytes, and from all stages before the 32-cell stage. The finding that TEC-3 is not expressed before the onset of embryonic transcription, which occurs at the eight-cell stage in the bovine, but only when the embryonic genome is active, makes it a potential marker for studying nuclear reprogramming after nuclear transfer. Nuclear transfer embryos were made by electrical fusion of blastomeres from morulae derived in vivo with enucleated metaphase II oocytes. Indirect immunofluorescence with the TEC-03 antibody showed that the TEC-3 antigen, present on blastomeres of the morula stage embryo, disappeared after fusion and was expressed again when the nuclear transfer embryos developed to the morula and blastocyst stage. These data suggest that the bovine embryonic nucleus may be able to revert to the equivalent of an earlier developmental stage when transferred to ooplasm, and is then capable of following the normal developmental program.