The incidence of psoriasis in Chile: an analysis of the National Waiting List Repository.

BACKGROUND: Psoriasis is a serious and chronic noncommunicable disease. However, the fundamental measure of disease occurrence, the incidence, has been scarcely reported globally. There are no previous studies of psoriasis incidence in Latin America. AIM: To estimate the incidence rates of psoriasis in Chile during 2016 and 2017 using an administrative database, the Waiting List Repository. METHODS: We examined referrals of psoriasis at onset, made by physicians to dermatologists, evaluated the agreement of diagnosis, and estimated the incidence of the disease considering the eligible population at risk. RESULTS: In most cases, the referrals corresponded to incident cases of psoriasis (73.3%; 95% CI: 66.6-79.2). The national incidence rates of psoriasis were 22.1 (95% CI: 21.1-23.1) and 22.7 (95% CI: 21.8-23.6) per 100 000 person-years in 2016 and 2017, respectively. The most common type of psoriasis was the late-onset type. We observed a high variation in the figures throughout the country, with a range from 0.75 (95% CI: 0.3-1.5) per 100 000 person-years in the Metropolitan region to 164.9 (95% CI: 138.6-195.1) per 100 000 person-years in the Aysen region. CONCLUSION: We describe for the first time the incidence of psoriasis in a Latin American country. Our findings could potentially guide collaborations to improve our global understanding of psoriasis in Latin America.

Optimising adjacent membrane segmentation and parameterisation in multicellular aggregates by piecewise active contours.

In fluorescence microscopy imaging, the segmentation of adjacent cell membranes within cell aggregates, multicellular samples, tissue, organs, or whole organisms remains a challenging task. The lipid bilayer is a very thin membrane when compared to the wavelength of photons in the visual spectra. Fluorescent molecules or proteins used for labelling membranes provide a limited signal intensity, and light scattering in combination with sample dynamics during in vivo imaging lead to poor or ambivalent signal patterns that hinder precise localisation of the membrane sheets. In the proximity of cells, membranes approach and distance each other. Here, the presence of membrane protrusions such as blebs; filopodia and lamellipodia; microvilli; or membrane vesicle trafficking, lead to a plurality of signal patterns, and the accurate localisation of two adjacent membranes becomes difficult. Several computational methods for membrane segmentation have been introduced. However, few of them specifically consider the accurate detection of adjacent membranes. In this article we present ALPACA (ALgorithm for Piecewise Adjacent Contour Adjustment), a novel method based on 2D piecewise parametric active contours that allows: (i) a definition of proximity for adjacent contours, (ii) a precise detection of adjacent, nonadjacent, and overlapping contour sections, (iii) the definition of a polyline for an optimised shared contour within adjacent sections and (iv) a solution for connecting adjacent and nonadjacent sections under the constraint of preserving the inherent cell morphology. We show that ALPACA leads to a precise quantification of adjacent and nonadjacent membrane zones in regular hexagons and live image sequences of cells of the parapineal organ during zebrafish embryo development. The algorithm detects and corrects adjacent, nonadjacent, and overlapping contour sections within a selected adjacency distance d, calculates shared contour sections for neighbouring cells with minimum alterations of the contour characteristics, and presents piecewise active contour solutions, preserving the contour shape and the overall cell morphology. ALPACA quantifies adjacent contours and can improve the meshing of 3D surfaces, the determination of forces, or tracking of contours in combination with previously published algorithms. We discuss pitfalls, strengths, and limits of our approach, and present a guideline to take the best decision for varying experimental conditions for in vivo microscopy.

Astrocyte-to-neuron communication through integrin-engaged Thy-1/CBP/Csk/Src complex triggers neurite retraction via the RhoA/ROCK pathway.

Two key proteins for cellular communication between astrocytes and neurons are αvß3 integrin and the receptor Thy-1. Binding of these molecules in the same (cis) or on adjacent (trans) cellular membranes induces Thy-1 clustering, triggering actin cytoskeleton remodeling. Molecular events that could explain how the Thy-1-αvß3 integrin interaction signals have only been studied separately in different cell types, and the detailed transcellular communication and signal transduction pathways involved in neuronal cytoskeleton remodeling remain unresolved. Using biochemical and genetic approaches, single-molecule tracking, and high-resolution nanoscopy, we provide evidence that upon binding to αvß3 integrin, Thy-1 mobility decreased while Thy-1 nanocluster size increased. This occurred concomitantly with inactivation and exclusion of the non-receptor tyrosine kinase Src from the Thy-1/C-terminal Src kinase (Csk)-binding protein (CBP)/Csk complex. The Src inactivation decreased the p190Rho GTPase activating protein phosphorylation, promoting RhoA activation, cofilin, and myosin light chain II phosphorylation and, consequently, neurite shortening. Finally, silencing the adaptor CBP demonstrated that this protein was a key transducer in the Thy-1 signaling cascade. In conclusion, these data support the hypothesis that the Thy-1-CBP-Csk-Src-RhoA-ROCK axis transmitted signals from astrocytic integrin-engaged Thy-1 (trans) to the neuronal actin cytoskeleton. Importantly, the ß3 integrin in neurons (cis) was not found to be crucial for neurite shortening. This is the first study to detail the signaling pathway triggered by αvß3, the endogenous Thy-1 ligand, highlighting the role of membrane-bound integrins as trans acting ligands in astrocyte-neuron communication.

Transactivation activity and nucleocytoplasmic transport of ß-catenin are independently regulated by its C-terminal end.

The key protein in the canonical Wnt pathway is ß-catenin, which is phosphorylated both in absence and presence of Wnt signals by different kinases. Upon activation in the cytoplasm, ß-catenin can enter into the nucleus to transactivate target gene expression, many of which are cancer-related genes. The mechanism governing ß-catenin's nucleocytoplasmic transport has been recently unvealed, although phosphorylation at its C-terminal end and its functional consequences are not completely understood. Serine 646 of ß-catenin is a putative CK2 phosphorylation site and lies in a region which has been proposed to be important for its nucleocytoplasmic transport and transactivation activity. This residue was mutated to aspartic acid mimicking CK2-phosphorylation and its effects on ß-catenin activity as well as localization were explored. ß-Catenin S6464D did not show significant differences in both transcriptional activity and nuclear localization compared to the wild-type form, but displayed a characteristic granular nuclear pattern. Three-dimensional models of nuclei were constructed which showed differences in number and volume of granules, being those from ß-catenin S646D more and smaller than the wild-type form. FRAP microscopy was used to compare nuclear export of both proteins which showed a slightly higher but not significant retention of ß-catenin S646D. Altogether, these results show that C-terminal phosphorylation of ß-catenin seems to be related with its nucleocytoplasmic transport but not transactivation activity.

Evaluating multiplexed next-generation sequencing as a method in palynology for mixed pollen samples.

The identification of pollen plays an important role in ecology, palaeo-climatology, honey quality control and other areas. Currently, expert knowledge and reference collections are essential to identify pollen origin through light microscopy. Pollen identification through molecular sequencing and DNA barcoding has been proposed as an alternative approach, but the assessment of mixed pollen samples originating from multiple plant species is still a tedious and error-prone task. Next-generation sequencing has been proposed to avoid this hindrance. In this study we assessed mixed pollen probes through next-generation sequencing of amplicons from the highly variable, species-specific internal transcribed spacer 2 region of nuclear ribosomal DNA. Further, we developed a bioinformatic workflow to analyse these high-throughput data with a newly created reference database. To evaluate the feasibility, we compared results from classical identification based on light microscopy from the same samples with our sequencing results. We assessed in total 16 mixed pollen samples, 14 originated from honeybee colonies and two from solitary bee nests. The sequencing technique resulted in higher taxon richness (deeper assignments and more identified taxa) compared to light microscopy. Abundance estimations from sequencing data were significantly correlated with counted abundances through light microscopy. Simulation analyses of taxon specificity and sensitivity indicate that 96% of taxa present in the database are correctly identifiable at the genus level and 70% at the species level. Next-generation sequencing thus presents a useful and efficient workflow to identify pollen at the genus and species level without requiring specialised palynological expert knowledge.

Computational methods for analysis of dynamic events in cell migration.

Cell migration is a complex biological process that involves changes in shape and organization at the sub-cellular, cellular, and supra-cellular levels. Individual and collective cell migration can be assessed in vitro and in vivo starting from the flagellar driven movement of single sperm cells or bacteria, bacterial gliding and swarming, and amoeboid movement to the orchestrated movement of collective cell migration. One key technology to access migration phenomena is the combination of optical microscopy with image processing algorithms. This approach resolves simple motion estimation (e.g. preferred direction of migrating cells or path characteristics), but can also reveal more complex descriptors (e.g. protrusions or cellular deformations). In order to ensure an accurate quantification, the phenomena under study, their complexity, and the required level of description need to be addressed by an adequate experimental setup and processing pipeline. Here, we review typical workflows for processing starting with image acquisition, restoration (noise and artifact removal, signal enhancement), registration, analysis (object detection, segmentation and characterization) and interpretation (high level understanding). Image processing approaches for quantitative description of cell migration in 2- and 3-dimensional image series, including registration, segmentation, shape and topology description, tracking and motion fields are presented. We discuss advantages, limitations and suitability for different approaches and levels of description.

[Cardiorespiratory fitness among adults in Germany: results of the German Health Interview and Examination Survey for Adults (DEGS1)]. / Kardiorespiratorische Fitness bei Erwachsenen in Deutschland: Ergebnisse der Studie zur Gesundheit Erwachsener in Deutschland (DEGS1).

A high level of fitness is an indicator for a good health state. Therefore, cardiorespiratory fitness was examined in the cross-sectional German Health Interview Survey for Adults (DEGS1). Data from 3030 test-qualified adults between 18 and 64 years old were assessed by means of a standardized submaximal cycle ergometer test. Test-qualified participants were significantly younger, more often men, less often obese and showed a better health state than those who were not test-qualified. The calculated physical work capacity at 75 % of the age-predicted maximum heart rate (PWC75%) in watts per kg bodyweight was among men 1.52 and among women 1.15. PWC75% declines by 4.2 % per age decade for men and 4.8 % for women. A higher socioeconomic status (SES) is associated with better fitness among women. No significant association was observed between SES and fitness among men. These findings can be used to develop target-group specific health-promotion interventions in order to enhance cardiorespiratory fitness. It is planned to calculate updated PWC reference values based on the DEGS1 data. An English full-text version of this article is available at SpringerLink as supplemental.

[Measurement of cardiorespiratory fitness in the German Health Interview and Examination Survey for Adults (DEGS1)]. / Messung der kardiorespiratorischen Fitness in der Studie zur Gesundheit Erwachsener in Deutschland (DEGS1).

A state of good fitness is related to a better health state and a lower mortality risk. In the German Health Interview and Examination Survey for Adults (DEGS1), aerobic fitness was measured among adults between 18 and 64 years old using a submaximal cycle ergometry test. The total sample comprised 5,263 persons, amongst those 3,111 were categorized as being test-qualified according to the Physical Activity Readiness-Questionnaire. There were 3,030 persons who absolved a submaximal exercise test according to the exercise protocol of the WHO (25/25/2). The test-participation rate was 57.2 % in relation to the total sample and 97.4 % among test-qualified persons. Apart from the continuous heart-rate monitoring, capillary blood was taken prior to starting the test and at the end of each workload stage for performing blood lactate analyses. The test ended when 85 % of the age-predicted maximal heart rate was exceeded. In all 11.9 % of the tests were terminated earlier, the mean exercise duration was 10.8 min, and the anticipated submaximal exertion in the highest workload stage was on average achieved with a mean of 15 on the 20-point RPE scale. The nationwide data can now be used for the national health monitoring system, epidemiological research and for the calculation of reference values. An English full-text version of this article is available at SpringerLink as supplemental.

[Daily ailments among healthy, middle-aged adults--situation report and explanatory approaches]. / Alltagsbeschwerden bei gesunden Probanden mittleren Alters--Situations- beschreibung und Erklärungsansätze. Sportwissenschaftliche Untersuchung zur körperlichen Leistungsfähigkeit bei gesunden Männern und Frauen im mittleren Lebensalter.

BACKGROUND: Physical performance steadily declines with increasing age even among healthy adults. METHODS: A sport scientific screening-battery was used to determine the relationship between physical performance--that is endurance, strength, coordination, flexibility--and typical daily ailments as measured by a questionnaire among 222 healthy, middle-aged women and men. Cardiopulmonary performance was estimated by a 2-km walking test. RESULTS: Cardiopulmonary performance declined significantly as a result of increasing age and increasing body-mass index. 44% of men and 29% of women reached substandard values when compared to norm tables. Daily ailments such as "Problems while climbing stairs" or "Breathing difficulty" showed a strong correlation to the estimated cardiopulmonary performance. In contrast, they were less influenced by strength or flexibility. The subjects were oblivious of the relationship between the decreased performance of the cardiovascular system and daily ailments. CONCLUSION: Performing a simple screening-battery may be a good chance to promote the participation of middle-aged and non-athletic people in an adequate and health oriented sports program.

Development of 3D architecture of uropathogenic Proteus mirabilis batch culture biofilms-A quantitative confocal microscopy approach.

This work studies the development of the 3D architecture of batch culture P. mirabilis biofilms on the basis of morpho-topological descriptors calculated from confocal laser scanning microscopy (CLSM) stacks with image processing routines. A precise architectonical understanding of biofilm organization on a morpho-topological level is necessary to understand emergent interactions with the environment and the appearance of functionally different progeny swarmer cells. P. mirabilis biofilms were grown on glass coverslips for seven days on LB broth and subjected to in situ immunofluorescence. Confocal image stacks were deconvolved prior to segmentation of regions of interest (ROI) that identify individual bacteria and extracellular material, followed by 3D reconstruction and calculation of different morpho-topological key descriptors. Results showed that P. mirabilis biofilm formation followed a five stage process: (i) reversible adhesion to the surface characterized by slow growth, presence of elongated bacteria, and absence of extracellular material, (ii) irreversible bacterial adhesion concomitant to decreasing elongation, and the beginning of extracellular polymer production, (iii) accelerated bacterial growth concomitant to continuously decreasing elongation and halting of extracellular polymer production, (iv) maturation of biofilm defined by maximum bacterial density, volume, minimum elongation, maximum extracellular material, and highest compaction, and (v) decreased bacterial density and extracellular material through detachment and dispersion. Swarmer cells do not play a role in P. mirabilis biofilm formation under the applied conditions. Our approach sets the basis for future studies of 3D biofilm architecture using dynamic in vivo models and different environmental conditions that assess clinical impacts of P. mirabilis biofilm.

Reproductive division of labour and thelytoky result in sympatric barriers to gene flow in honeybees (Apis mellifera L.).

Determining the extent and causes of barriers to gene flow is essential for understanding sympatric speciation, but the practical difficulties of quantifying reproductive isolation remain an obstacle to analysing this process. Social parasites are common in eusocial insects and tend to be close phylogenetic relatives of their hosts (= Emery's rule). Sympatric speciation caused by reproductive isolation between host and parasite is a possible evolutionary pathway. Socially parasitic workers of the Cape honeybee, Apis mellifera capensis, produce female clonal offspring parthenogenetically and invade colonies of the neighbouring subspecies A. m. scutellata. In the host colony, socially parasitic workers can become pseudoqueens, an intermediate caste with queenlike pheromone secretion. Here, we show that over an area of approximately 275.000 km², all parasitic workers bear the genetic signature of a clone founded by a single ancestral worker genotype. Any gene flow from the host to the parasite is impossible because honeybee workers cannot mate. Gene flow from the parasite to the host is possible, as parasitic larvae can develop into queens. However, we show that despite sympatric coexistence for more than a decade, gene flow between host and social parasite (F(st) = 0.32) and hybridizations (0.71%) are rare, resulting in reproductive isolation. Our data suggest a new barrier to gene flow in sympatry, which is not based on assortative matings but on thelytoky and reproductive division of labour in eusocial insects, thereby suggesting a new potential pathway to Emery's rule.

Confined displacement algorithm determines true and random colocalization in fluorescence microscopy.

The quantification of colocalizing signals in multichannel fluorescence microscopy images depends on the reliable segmentation of corresponding regions of interest, on the selection of appropriate colocalization coefficients, and on a robust statistical criterion to discriminate true from random colocalization. Here, we introduce a confined displacement algorithm based on image correlation spectroscopy in combination with Manders colocalization coefficients M1(ROI) and M2(ROI) to quantify true and random colocalization of a given florescence pattern. We show that existing algorithms based on block scrambling exaggerate the randomization of fluorescent patterns with resulting inappropriately narrow probability density functions and false significance of true colocalization in terms of p values. We further confine our approach to subcellular compartments and show that true and random colocalization can be analysed for model dendrites and for GABA(B) receptor subunits GABA(B)R1/2 in cultured hippocampal neurons. Together, we demonstrate that the confined displacement algorithm detects true colocalization of specific fluorescence patterns down to subcellular levels.

Lipid domains in giant unilamellar vesicles and their correspondence with equilibrium thermodynamic phases: a quantitative fluorescence microscopy imaging approach.

We report a novel analytical procedure to measure the surface areas of coexisting lipid domains in giant unilamellar vesicles (GUVs) based on image processing of 3D fluorescence microscopy data. The procedure involves the segmentation of lipid domains from fluorescent image stacks and reconstruction of 3D domain morphology using active surface models. This method permits the reconstruction of the spherical surface of GUVs and determination of the area fractions of coexisting lipid domains at the level of single vesicles. Obtaining area fractions enables the scrutiny of the lever rule along lipid phase diagram's tie lines and to test whether or not the coexistence of lipid domains in GUVs correspond to equilibrium thermodynamic phases. The analysis was applied to DLPC/DPPC GUVs displaying coexistence of lipid domains. Our results confirm the lever rule, demonstrating that the observed membrane domains correspond to equilibrium thermodynamic phases (i.e., solid ordered and liquid disordered phases). In addition, the fact that the lever rule is validated from 11 to 14 randomly selected GUVs per molar fraction indicates homogeneity in the lipid composition among the explored GUV populations. In conclusion, our study shows that GUVs are reliable model systems to perform equilibrium thermodynamic studies of membranes.

Pheromonal dominance and the selection of a socially parasitic honeybee worker lineage (Apis mellifera capensis Esch.).

The recent invasion by self-replicating socially parasitic Cape honeybee workers, Apis mellifera capensis, of colonies of the neighbouring African subspecies Apis mellifera scutellata represents an opportunity to study evolution of intraspecific parasitism in real time. As honeybee workers compete pheromonally for reproductive dominance, and as A. m. capensis workers readily produce queen-like pheromones, we hypothesized that these semiochemicals promoted the evolution of intraspecific social parasitism. Remarkably, the offspring of a single worker became established as a parasite in A. m. scutellata's range. This could have resulted from extreme selection among different clonal parasitic worker lineages. Using pheromonal contest experiments, we show that the selected parasitic lineage dominates in the production of mandibular gland pheromones over all other competitors to which it is exposed. Our results suggest that mandibular gland pheromones played a key role in the evolution of intraspecific social parasitism in the honeybee and in the selection of a single genotype of parasitic workers.

ATP steal between cation pumps: a mechanism linking Na+ influx to the onset of necrotic Ca2+ overload.

We set out to identify molecular mechanisms underlying the onset of necrotic Ca(2+) overload, triggered in two epithelial cell lines by oxidative stress or metabolic depletion. As reported earlier, the overload was inhibited by extracellular Ca(2+) chelation and the cation channel blocker gadolinium. However, the surface permeability to Ca(2+) was reduced by 60%, thus discarding a role for Ca(2+) channel/carrier activation. Instead, we registered a collapse of the plasma membrane Ca(2+) ATPase (PMCA). Remarkably, inhibition of the Na(+)/K(+) ATPase rescued the PMCA and reverted the Ca(2+) rise. Thermodynamic considerations suggest that the Ca(2+) overload develops when the Na(+)/K(+) ATPase, by virtue of the Na(+) overload, clamps the ATP phosphorylation potential below the minimum required by the PMCA. In addition to providing the mechanism for the onset of Ca(2+) overload, the crosstalk between cation pumps offers a novel explanation for the role of Na(+) in cell death.

Ultraviolet exposure of thymocytes: selective inhibition of apoptosis.

PURPOSE: To evaluate selective effects of ultraviolet (UV) irradiation on spontaneous and induced apoptosis in freshly extracted mice thymocytes. MATERIALS AND METHODS: Cells were exposed to UV radiation with emission peaks of 365 nm (UVA) exposures of 1620-10200 J m(-2), of 312 nm (UVB) exposures of 34-1620 J m(-2) or of 254 nm (UVC) exposures of 1.5-1620 J m(-2), and incubated for 5.5 h with or without hydrocortisone, phorbol-12-myristate-13-acetate or anti-Fas antibody. Additionally, cells were irradiated with gamma-rays (5 Gy) before UVB exposure (408 J m(-2)) at different times. Apoptosis was quantified by DNA fragmentation. RESULTS: Up to an irradiation of 5000 J m(-2), UVA exposure did not show any effect on thymocyte apoptosis, while at 10200 J m(-2) irradiation, considerable DNA fragmentation was observed. In contrast, UVB and UVC irradiation clearly inhibited natural and cortisone-induced apoptosis. Moreover, UVB inhibited apoptosis triggered by phorbol-12-myristate-13-acetate and gamma-irradiation, but not by anti-Fas antibody. CONCLUSIONS: The response of mouse thymocytes in culture to UV irradiation strongly depends on the wavelength used. It is suggested that either a survival or an apoptotic pathway occurs depending on the physiological state of the cell, spectral composition of the UV light and cell type. The possible involvement of extracellular signal-regulated kinase and stress-activated protein kinase/c-Jun N-terminal kinase in the apoptotic pathway is discussed.

Specific developmental gene silencing in the honey bee using a homeobox motif.

Manipulating the expression of genes in species that are not currently used as genetic models will provide comparative insights into the evolution of gene functions. However the experimental tools in doing so are limited in species that have not served as models for genetic studies. We have examined the effects of double stranded RNA (dsRNA) in the honey bee, an insect with considerably basic scientific interest. dsRNA derived from a 300 bp stretch of the E30 homeobox motif was injected into honey bee embryos at the anterior pole in the preblastoderm stage. We found that the dsRNA fragment successfully disrupted the protein expression of the target gene throughout the whole embryo. The disruption caused deficient phenotypes similar to known loss of function mutants of Drosophila engrailed, whereas embryos injected with nonsense dsRNA showed no abnormalities. We show that the large size of the honey bee egg (D: 0.3 mm, L: 1.6 mm) and the long preblastoderm stage (11-12 h) can be exploited to generate embryos with partial disruption of gene function, which may provide an elegant alternative to classical chimeric analyses. This is the first report of targeted disruption of gene function in the honey bee, and the results prove that the chosen target gene is a functional ortholog to engrailed in Drosophila.

Cholesterol induced variations of membrane dynamics related to the induction of apoptosis in mouse thymocytes.

PURPOSE: To evaluate the involvement of cholesterol induced variations of membrane dynamics in mouse thymocyte apoptosis. MATERIALS AND METHODS: Membranes of thymocytes of RK mice were enriched with cholesterol using methyl-beta-cyclodextrins as carriers. Spontaneous apoptosis was compared with apoptosis induced either by X-irradiation, by treatment with dexamethasone (DEX), and by phorbol-12-myristate-13-acetate (PMA). Apoptotic cells were quantified by means of flow cytofluorometry. RESULTS: Small amounts of incorporated cholesterol enhance the cellular sensitivity for spontaneous apoptosis whereas larger amounts of incorporated cholesterol protect against spontaneous apoptosis and apoptosis induced by irradiation, DEX, or PMA. CONCLUSIONS: Cholesterol exerts specific rigidity effects on lipid membranes which have been shown to be involved in thymocyte apoptosis. The general effect of higher concentrations of cholesterol protecting against apoptosis hints towards a central protective mechanism. This study believes that either cholesterol paralyses great parts of the cell metabolism or that the apoptotic chain reaction is interrupted at a central point due to protection of membrane lipid regions from oxidative stress.

Methyl-beta-cyclodextrins and liposomes as water-soluble carriers for cholesterol incorporation into membranes and its evaluation by a microenzymatic fluorescence assay and membrane fluidity-sensitive dyes.

A variety of methods to incorporate cholesterol into lipid membrane systems have been applied with varying success. We tested an incorporation method based on cholesterol-loaded methyl-beta-cyclodextrins and compared it to a method that uses cholesterol-loaded liposomes. With methyl-beta-cyclodextrin, we increased the cholesterol content in microsomal membranes to almost the fourfold of the original content. With cholesterol-loaded liposomes instead, we achieved an elevation of 140%. Short incubation times and well-defined carrier properties favor the beta-cyclodextrin method. For direct detection of membrane cholesterol, we slightly modified a microenzymatic fluorescence assay originally developed for precise cholesterol detection in serum. Without the need to perform lipid extraction, this assay was reliable for cholesterol detection in liposomes and in microsomes. Additionally, we compared the sensitivity of the fluidity-sensitive fluorescent dyes pyrene, pyrene-methanol, bis-pyrene, 1-6-phenyl-1,3,5,-hexatrien, and 1-(4-trimethylammoniumphenyl)-6-phenyl-1,3,5,-hexatrien in order to detect cholesterol indirectly by the dynamically relevant changes exerted on lipid matrices. These dyes differ not only in their membrane location but also in their dynamical behavior. We calibrated the dyes in liposomes of defined cholesterol content and used the most suited ones to follow and quantify the cholesterol incorporation into liposomal and microsomal membranes.

[Urologic complications after implantation of aortofemoral blood vessel prosthesis]. / Urologische Komplikationen nach aortofemoraler Gefässprothesenimplantation.

After implantation of aorto-femoral grafts, primary ureteral lesions and secondary ureteral obstructions are the most important urological complications. Surgical repair carried out as quickly as possible, including reanastomosis without tension and covering with a peritoneal patch or omentum interposition, seems the best means of preventing secondary complications. In the case of secondary obstructions, the interval between implantation of the graft and the diagnosis of obstruction has to be considered. A wait-and-see strategy is justified in the case of early obstruction without symptoms during the 1st year because of the high rate of spontaneous remission. Obstructions that appear more than 1 year after operation or symptomatic obstructions have to be treated immediately (i.e. duodenojejunal stent, percutaneous nephrostomy). If repeated obstructions after removal of stents or nephrostomies are noted, surgical repair seems to be indicated. Stents or nephrostomies as definitive procedures are appropriate only in patients in whom surgical revision is not possible or desirable.