[Characterization of ENU-mutant mice. Animal models for human diseases using morphological and molecular methods]

Following sequencing of the human genome there are new challenges to decipher the knowledge concerning gene function and the role of gene interactions and pathways leading to disease. Mouse models have proven to be an ideal tool for this purpose. Point mutations induced by chemical mutagenesis by N-ethyl-N-nitrosourea (ENU) offer possibilities for the analysis of the phenotypic outcome of a single base pair exchange on the entire organism. The Munich ENU mouse mutagenesis project is part of the worldwide efforts to obtain mutations for each gene. The generation of new alleles or allelic series offers relevant insights into the relevance of single gene sections. Various mouse models for human diseases have been generated by a systematic large-scale genome-wide phenotyping screen in the last decade. This work illustrates how the implementation of the ENU mouse mutagenesis project with gene identification and parallel high-throughput screening is taking advantage of local cooperation with experienced phenotyping groups at the Helmholtz Zentrum München, leading to major advances in the functional analysis of the mammalian genome.

Linking energy metabolism to dysfunctions in mitochondrial respiration--a metabolomics in vitro approach

The study presented here describes the application of metabolite profiling of highly polar, intracellular metabolites after incubation of a mammalian fibroblast cell line with inhibitors of mitochondrial function. A metabolomics approach was used to assess the complex response of the cellular energy metabolism. Metabolic profiles of phosphorylated and carboxylated intracellular metabolites were assessed by UPLC-MS/MS and used to predict the mode of mitochondrial toxicity. Based on distinct metabolic patterns, multivariate data analysis allowed for the discrimination of two groups of toxins: inhibitors of the electron transport in mitochondrial membranes (complex IV inhibitors) and uncouplers of oxidative phosphorylation. Beyond these known interferences, metabolic profiling was able to reveal additional inhibitory effects on the cellular energy metabolism. Most prominently, for three of the toxins, metabolic patterns also disclosed an enhanced activity of the glycerol phosphate shuttle inferring the inhibition of NADH dehydrogenase at complex I. Secondly, inhibition of the electron transport was accompanied by a limiting availability of citric acid cycle intermediates and aspartate. Concomitantly, specific perturbations of the purine nucleotide cycle were observed. We have shown here that metabolomic approaches may assist to predict complex modes of action of toxic compounds on cellular level as well as to unravel specific dysfunctions in the energy metabolism.

The inventory of depressive symptomatology is more sensitive to changes in depressive symptomatology than the hamilton depression rating scale in patients with minor depression

Background

Depression rating scales play a decisive role in the assessment of the severity of depression and the evaluation of the efficacy of antidepressant treatments. The Hamilton Depression Rating Scale (HAMD) is regarded as the ‘gold standard’; nevertheless, studies suggest that the Inventory of Depressive Symptomatology (IDS) is more sensitive to detect symptom changes. The aim of the present study was to investigate whether the IDS is more sensitive in detecting changes in depression symptoms in patients with mild major, minor or subsyndromal depression (MIND).

Methods

Biweekly IDS-C28 and HAMD17 data from 340 patients of a 10-week randomized, placebo-controlled trial comparing the effectiveness of sertraline and cognitive-behavioural therapy in patients with MIND were analysed. We investigated sensitivity to change for both scales1)

Results

The IDS-C28 was more sensitive in detecting changes in depression symptomatology over the treatment course as well as for different severity levels, especially in patients with a low depression severity. It assesses the DSM-IV criteria more thoroughly, is better able to track the change of cognitive symptoms and to identify residual symptoms.

Conclusions

Both scales are well able to assess depressive symptomatology. However, the IDS-C28 surpasses the HAMD17 in detecting small changes especially in the core symptoms of depression. This is important for an optimal treatment by capturing early improvements, enabling prompt reactions and detecting residual symptoms.

Microcrystallinity in α-Si, Ge:H, F Alloys

Microcrystalline inclusions in hydrogenated and fluorinated amorphous silicongermanium alloys, α-Si, Ge:H, F, were studied. Microcrystals grown during RF or DC glow discharge deposition from SiF4, GeF4 and H2 consist of either pure Si or Ge. Microcrystals produced by thermal annealing of initially amorphous alloys are either microcrystalline Ge or microcrystalline Si-Ge alloys depending on the annealing temperature. Values for the grain size were calculated from X-ray diffraction (XRD) and Raman spectra. The grain size of the “grown” microcrystal ranges from 8 to 60 nm. These grown grains exhibit preferential orientation of the (220) planes parallel to the substrate surface. Microcrystals produced by high-temperature anneal are randomly oriented. Scanning electron micrographs of as-grown samples show protruding platelets several 100 nm long and several 10 nm wide. Fractured cross sections exhibit columnar structure.

Preparation of α-(Si.Ge):H Alloys by D.C. Glow Discharge Deposition

We report the preparation of α-(Si.Ge):H alloy films by decomposition of SiF4, GeF4, and H2 in a d.c. glow discharge. Germanium is incorporated very efficiently from GeF4. The germanium content and optical gap canbe controlled by varying the GeF4 flow while keeping the SiF4 and H2 flows constant. The films, all prepared at 300 ºC substrate temperature, exhibit high photo- to dark-conductivity ratios for compositions of up to -25% germanium.

Time-of-Flight Measurements in a-Si:H Between Room Temperature and 130° C°

The drift mobility μd and the mobility-lifetime product μτ in undoped a-Si:H have been studied up to 130°C. The electron μde is temperature-activated with Eae = 0.13 to 0.16 eV. The electron (μτ)e increases with temperature T. For hole transport, we observe the transition from dispersive to non-dispersive transport with increasing T. The hole μdh is ∼ 1/100 of μde, and is activated with Eah = 0.34 to 0.48eV. The hole (μτ)h does not change much with T. A computer simulation demonstrates the high sensitivity of μd to the band tail width.

The Structure of a-Si:H,F/a-Si,Ge:H,F Interfaces

We study the interface between un-alloyed a-Si:H,F and an a-Si0.4,Ge0.6:H,F alloy using superlattice structures. From infrared spectroscopy we estimate a width of 8 A for the excess hydrogen layer, and X-ray diffraction data give us a width of 2Å contributing to the width of the diffraction peak. Vibrational Raman scattering data show that the ratios of the number of Si-Si, Ge-Ge and Si-Ge bonds is not altered by changing the number of interfaces. This fact allows us to establish an upper limit for the interface width of 3 atomic layers, i.e. one layer in each partner plus an intermediate layer.

Amorphous Silicon Films from Dichlorosilane and Hydrogen

We deposited a-Si:H thin-films by PECVD of dichlorosilane (SiH2Cl2) diluted with H2 in a DC-triode glow-discharge reactor. The dilution ratio, given as the ratio of H2 to SiH2Cl2 flows, was varied from 0 to 130 and the pressure was varied from 0.3 to 0.75 Torr as the hydrogen fraction was increased. We report on the properties of the deposition plasma and the resulting films; namely the plasma pressure-voltage characteristics and the films' chemical composition, structure, and optoelectronic properties. For hydrogen dilution ratios greater than 2:1, dense, rigid films are deposited, with optical bandgaps from 1.75 to 1.9 eV. With increasing hydrogen dilution a growth rate of 5 Å/s is maintained while photoconductivities increase and defect densities decrease. The best films are obtained at a dilution ratios of 16:1 to 32:1, where we have obtained a dark conductivity of 10−13 S/cm, a photoconductivity of 2×10−7 S/cm (at G=1020 cm-3 s−1) and a defect density of 1.5×1016 cm−3.

Thin Film Transistors of Microcrystalline Silicon Deposited by Plasma Enhanced-CVD

We fabricated top gate TFTs of microcrystalline silicon (μc-Si) deposited at 360 °C. The TFTs have field-effect electron mobilities of up to 7.9 cm2/Vs in the saturation regime and 5.8 cm2/Vs in the linear regime. The highest ION/IOFF ratio is 105. Typical values for Vth is 6.5 V and for the subthreshold slope is 1.7 V/decade. The μc-Si is grown by PE-CVD from a source gas mixture of SiH4, SiF4 and H2, with a typical flow ratio of 1:20:200, at a pressure of 120 Pa and a power density of 160 mW/cm2. The TFT structure is built on un-passivated Coming 7059 glass, with 300 n+ μc-Si, 60 nm n+ μc-Si source and drain contact layers, 200 nm SiO2 or 300 nm SiNx gate insulator, and 100 nm Al gate, source and drain electrodes.

TFT Performance - Material Quality Correlation for a-Si:H Deposited at high Rates

We evaluated the characteristics of a-Si:H/a-SiNx:H thin film transistors (TFTs), and of separately deposited a-Si:H films, as functions of the a-Si:H deposition power in a high-rate, large-area, 40 MHz PE-CVD system. TFT performance and a-Si:H film properties improve with decreasing power density and deposition rate. However, low defect density a-Si:H material was deposited at rates as high as 1500 Å/min. TFTs with gate nitride deposited at 1000 A/min show excellent I-V characteristics when the a-Si:H deposition power is low enough. The TFT electron mobility in the linear regime correlates well with the Urbach energy of the a-Si:H films, suggesting that the quality of the a-Si: H controls the performance of our TFTs.

a-Si:H Thin-Film Transistors on Rollable 25-µ;m Thick Steel Foil

We report the first amorphous silicon thin film transistors (TFTs) on flexible, ultra-thin substrates of 25 µm thick stainless steel foil. The transistors remain operational under convex or concave bending down to 2.5 mm radius of curvature. Taking advantage of the flexibility and resiliency of these devices, we have successfully fabricated TFTs using only xerographic toner masks printed directly on to the steel substrate and using mechanical alignment in the laser printer to obtain the necessary overlay accuracy. The goal of our work is to develop a foldable active-matrix transistor backplane, at low cost and high throughput, for use in highly rugged and portable applications such as foldable intelligent maps. Our results suggest that such foldable backplane circuits are feasible.

Direct Writing and Lift-Off Patterning of Copper Lines at 200°C Maximum Process Temperature

We adapted a new technique for depositing copper lines, at a maximum process temperature of 200°C. The technique is based on the decomposition of copper hexanoate by UV light, followed by annealing in H2 [1]. A copper film resistivity of 8 μΩcm is obtained. We patterned this copper metallization on Corning 7059 glass substrates by three different techniques, including exposure through a shadow mask, lift-off of xerographic toner, and direct writing.

a-Si:H TFTs Made on Polyimide Foil by PE-CVD at 150°C

We have fabricated high-performance amorphous silicon thin-film transistors (a-Si:H TFTs) on 2 mil. (51 µm) thick polyimide foil substrates. The TFT structure was deposited by r.f.-excited plasma enhanced chemical vapor deposition (PECVD). All TFT layers, including the gate silicon nitride, the undoped, and the n+ amorphous silicon were deposited at a substrate temperature of 150°C. The transistors have inverted-staggered back-channel etch structure. The TFT off-current is ∼ 10−12 A, the on-off current ratio is > 107, the threshold voltage is 3.5 V, the sub-threshold slope is ∼ 0.5V/decade, and the linear-regime mobility is ∼ 0.5 cm2V−1s−1. We compare the mechanical behavior of a thin film on a stiff and on a compliant substrate. The thin film stress can be reduced to one half by changing from a stiff to a compliant substrate. A new equation is developed for the radius of curvature of thin films on compliant substrates.

a-Si:H Thin Film Transistors on Rollable 25-μM Thick Steel Foil

We report the first amorphous silicon thin film transistors (TFTs) on flexible, ultra-thin substrates of 25 μm thick stainless steel foil. The transistors remain operational under convex or concave bending down to 2.5 mm radius of curvature. Taking advantage of the flexibility and resiliency of these devices, we have successfully fabricated TFTs using only xerographic toner masks printed directly on to the steel substrate and using mechanical alignment in the laser printer to obtain the necessary overlay accuracy. The goal of our work is to develop a foldable active-matrix transistor backplane, at low cost and high throughput, for use in highly rugged and portable applications such as foldable intelligent maps. Our results suggest that such foldable backplane circuits are feasible.

Low Temperature Growth of Nanocrystalline Silicon From SiF4 + SiH4

The electrical conductivity of nc-Si films grown from SiF4 and H2 with constant arsenic doping rises from 10-5 to 10 Scm-1 as the thickness rises from ˜ 0.1 to 1 μm. This variation demonstrates the strong influence of film structure on conductivity. We show that the conductivity of undoped nc-Si films of constant thickness can be varied by adding SiH4 to the SiF4 and H2 source gas.

Jet Printing of Copper Lines at 200°C Maximum Process Temperature

We describe a new technique for making copper lines by printing a precursor pattern that is converted to copper, at a maximum process temperature of 200°C. We formed copper metallization patterns on 80 μm thick Coming 0211 glass substrates by jet printing. Continuous lines of copper with resistivity of 10 μΩcm have been obtained. We successfully applied this technique to the direct printing of copper source and drain contacts for amorphous silicon thinfilm transistors. The TFTs are bottom gate back-channel etched structures, with the silicon stack made by RF excited PE-CVD. The TFT process uses only printing for all masking steps, by employing laser-printed toner etch masks, and using the printed copper as the mask for the back channel etch. The transistor ON/OFF current ratio is 105. The process for copper printing represents a further step toward an all-printed TFT technology.

Two highly validated multiplexes (12-plex and 8-plex) for species delimitation and parentage analysis in oaks (Quercus spp.)

Multiplex PCR is a fast and cost-effective technique allowing increased genotyping throughput of microsatellites. We developed two multiplexes for Quercus petraea and Q. robur, a 12-plex of EST-SSRs (eSSRs) and an 8-plex of genomic SSRs (gSSRs). We studied the origin of allele calling errors at the human reader and software levels. We showed that the robustness of allele identification can be improved by binning on raw peak sizes prior to genetic data analysis. We checked through simulation the power of these markers for species delimitation and hybrid detection. The resolution achieved with all 20 markers was greatly improved compared to that of previous studies based on a subset of the markers. Preliminary PCR tests suggest that these multiplexes might be useful to study other oak species as well. The strategy used for multiplex microsatellite development (from PCR conditions to the definition of allele calling rules) should be broadly applicable.

Association between cingulum bundle structure and cognitive performance: an observational study in major depression

BACKGROUND

Major depression can be regarded as a systemic neurobehavioral disorder resulting from dysfunction of the limbic-cortical networks. The cingulum bundle represents a major association fiber tract of those networks. The aim of our study was to determine the association of brain structural tissue markers of the cingulum bundle and cognitive function in patients with major depression.

METHODS

Region-of-interest-based analyses of the middle-anterior and middle-posterior cingulum bundle fractional anisotropy (FA) and mean diffusivity (MD) using color-coded diffusion-tensor imaging and neuropsychological assessment in 14 patients with major depression.

RESULTS

FA of the middle-anterior and middle-posterior cingulum bundle was significantly correlated to the performance in a planning and divided attention task. Furthermore, MD of the middle-posterior cingulum bundle was significantly correlated to a planning task. There was no significant correlation between FA and MD of the cingulum bundle and selective attention or memory.

CONCLUSIONS

Brain structural tissue markers of the middle-anterior and middle-posterior cingulum bundle were found to be associated with executive functioning and divided attention in patients with major depression. Disconnection within the limbic-cortical networks may underlay cognitive dysfunction in major depression.

Bet v 1 and its homologous food allergen Api g 1 stimulate dendritic cells from birch pollen-allergic individuals to induce different Th-cell polarization

BACKGROUND

Bet v 1 is the most relevant sensitizing protein for birch pollen (BP)-allergic individuals. Its homologues from plant foods are mainly involved in allergic reactions caused by IgE cross reactivity. We aimed to evaluate the polarizing effect of dendritic cells (DCs) pulsed with Bet v 1, Mal d 1, Api g 1 or Dau c 1 on Th-cell responses.

METHODS

Immature DCs were generated from peripheral blood monocytes of BP-allergic and healthy donors by culture with GM-CSF and IL-4 and subsequently pulsed with allergens in combination with maturation factors. Cell surface markers were analysed by FACS. Mature DCs were co-cultured with autologous Th cells and T-cell proliferation and cytokine profiles were determined.

RESULTS

In co-culture, mature allergen-pulsed DCs induced autologous Th cells of BP-allergic donors to proliferate significantly more than those of healthy individuals. Exposure of DCs from BP-allergic donors to Bet v 1 resulted in a robust Th2 skewing with significantly higher quantities of IL-5 and elevated IL-13 compared to maturation factors. In contrast, Api g 1-primed DCs from BP allergics significantly enhanced the production of the Th1 cytokine IFN-γ and significantly down-regulated IL-13 compared to maturation factors. In healthy donors, no significant cytokine production could be detected.

CONCLUSION

Bet v 1 in contrast to homologous food allergens seems to possess distinct molecular features that enable it to condition DCs from BP-allergic donors to induce allergen-specific T-cell proliferation and Th2 polarization.

Automated methods for detecting lameness and measuring analgesia in dairy cattle

The objective was to assess gait, automated measures of weight distribution among the legs, and daily activity as methods for detecting lameness in dairy cows and measuring pain mitigation by nonsteroidal antiinflammatory drugs. Fifty-seven lactating cows (28 of which were lame) were injected twice with ketoprofen (3.0 mg/kg i.m.) or isotonic saline solution. Gait scores (numerical rating system, NRS), time spent lying down, frequency of steps, and weight distribution among legs when standing before, during, and after injections were measured to assess whether automated measures of activity can detect lameness and the effect of analgesic drugs in cows. Lame cows (NRS >3) shifted weight between contralateral legs more often (SD of the weight applied: 31.1+/-2.1 vs. 24.5+/-1.9kg), had a greater asymmetry in the weight applied to the rear legs (leg weight ratio=0.78+/-0.02 vs. 0.87+/-0.02), had longer lying bouts (94.0+/-4.9 vs. 78.2+/-5.8min), and walked slower (1.28+/-0.3 vs. 1.42+/-0.3 m/s) than nonlame cows. Variability over time (SD) of the weight applied to the rear legs was the most accurate predictor of whether a cow was lame or not (area under the curve=0.71). The SD of the weight applied to the rear legs decreased on the days when ketoprofen was given compared with the day before and after (18 and 12% decrease for lame and nonlame cows, respectively). Ketoprofen did not affect any other measure. Measures of weight shifting between legs while cows are standing have potential as an automated method of detecting lameness and analgesia.

Expression of the high mobility group A1 (HMGA1) and A2 (HMGA2) genes in canine lymphoma: analysis of 23 cases and comparison to control cases

Overexpression of high mobility group A (HMGA) genes was described as a prognostic marker in different human malignancies, but its role in canine haematopoietic malignancies was unknown so far. The objective of this study was to analyse HMGA1 and HMGA2 gene expression in lymph nodes of canine lymphoma patients. The expression of HMGA1 and HMGA2 was analysed in lymph node samples of 23 dogs with lymphoma and three control dogs using relative quantitative real-time RT-PCR. Relative quantity of HMGA1 was significantly higher in dogs with lymphoma compared with reference samples. HMGA2 expression did not differ between lymphoma and control dogs. With the exception of immunophenotype, comparison of disease parameters did not display any differences in HMGA1 and HMGA2 expression. The present findings indicate a role of HMGA genes in canine lymphoma. This study represents the basis for future veterinary and comparative studies dealing with their diagnostic, prognostic and therapeutic values.

The catechol o-methyltransferase (COMT) val(158)met polymorphism modulates the association of serious life events (SLE) and impulsive aggression in female patients with borderline personality disorder (BPD)

OBJECTIVE

We analyzed i) the effects of serious life events (SLE) on impulsive aggression, and ii) modulating effects of the COMT Val(158)Met polymorphism on the association between SLEs and impulsive aggression in borderline personality disorder (BPD).

METHOD

One hundred and twelve female BPD patients from Germany were included in this study. Impulsive aggression was assessed by the Buss-Durkee-Hostility Inventory (BDHI).

RESULTS

Childhood sexual abuse was associated with lower BDHI sum score (P = 0.003). In COMT Val(158)Val carriers, but not in Val/Met and Met/Met carriers, childhood sexual abuse and the cumulative number of SLEs were associated with lower BDHI sum scores (P < 0.05).

CONCLUSION

This study analyzing a specific gene x environment interaction in female BPD patients suggests an association between SLEs and impulsive aggression, as well as a modulating effect of the COMT Val(158)Val genotype on the relation between SLEs and impulsive aggression.

Non-invasive approaches to visualize the endothelin axis in vivo using state-of-the-art molecular imaging modalities

The endothelin axis plays a major role in cardiovascular diseases and a number of human cancers. This review summarizes the work that has been published in the past ten years using labeled endothelin receptor ligands for the visualization of endothelin receptor expression in vivo.

Occult incontinence in women with pelvic organ prolapse - Does it matter?

Objective

Many surgeons perform an anti-incontinence procedure during prolapse surgery in women in whom occult stress urinary incontinence has been demonstrated. Others prefer a two-step approach. It was the aim of the study to find out how many women really need a second operation and if a positive cough stress test with the prolapse reduced is associated with the development of stress urinary incontinence after prolapse surgery.

Methods

233 women were operated for primary or recurrent prolapse without complaining of SUI. Preoperatively, 53/233 women had a full urogynecological workup with the prolapse reduced. Postoperatively, if the patient suffered from stress urinary incontinence, an anti-incontinence surgery was performed.

Results

19/53 (35.8%) women who had a stress test with the prolapse reduced before surgery were defined as occult stress incontinent. Only 3 women (15.8%) of these 19 women developed symptoms of incontinence after prolapse surgery and had to be operated because of that. 18/233 (7.7%) complained of SUI 6 weeks to 6 months after surgery and received a TVT-tape.

Conclusion

The incidence of stress urinary incontinence manifesting after prolapse surgery is low in this study with 7.7%. This fact and the possible severe side effects of an incontinence operation justify a two-step approach if the patient is counseled and agrees. However, there is a small subgroup of women (3/19, 15.8%) with preoperative OSUI and SUI after surgery, who would benefit from a one-step approach. Further research is required to identify these women before surgical intervention.

[Obesity as a risk factor for prostate cancer: role for adipocytokines and involvement of tyrosine kinase pathway]

PURPOSE

Obesity is considered to be a risk factor for prostate cancer. Mitogenic actions of leptin, an adipocyte-derived hormone in a variety of cancer cell types have been identified. We have investigated the proliferative effects of leptin on human prostate cancer cells and assessed the role of tyrosine kinase signalling in mediating these actions.

MATERIALS AND METHODS

Two human androgen-resistant prostate cancer cell lines and one androgen-sensitive human prostate adenocarcinoma cell line were treated with leptin (5-100 ng / mL) for up to 48 hours. Under serum-free conditions, cell proliferation was measured using an enzyme-linked colorimetric assay. Furthermore, phosphorylation of a downstream component of MAPK (ERK1 / 2) was detected by Western blotting and a specific inhibitor of MAPK (PD98059; 40 microM) was used to evaluate the role of this signalling pathway.

RESULTS

Leptin dose-dependently increased the cell number in both androgen-resistant cell lines after 24 h and 48 h of incubation (percent of control: DU145 = 194.6 +/- 5.9 %, PC-3 = 177.9 +/- 6.8 %; 100 ng / mL leptin; 48 h; p < 0.001). Conversely, leptin's proliferative effect on the androgen-sensitive cell line was less pronounced (percent of control: LNCaP = 112.3 +/- 6.1 %; 100 ng / mL leptin; 48 h). Leptin also caused dose-dependent ERK1 / 2 phosphorylation in both androgen-resistant cell lines. In addition, pre-treatment with PD98059 inhibited these responses and attenuated leptin's mitogenic action.

CONCLUSIONS

Data from this in vitro study suggest an association between obesity-associated hyperleptinemia and an increased risk for prostate cancer. Further investigations are necessary to clarify whether these data have clinical relevance regarding the use as a prognostic marker for predicting the timing of the occurrence of androgen resistency.

Phenotypic and pathomorphological characteristics of a novel mutant mouse model for maturity-onset diabetes of the young type 2 (MODY 2)

Several mutant mouse models for human diseases such as diabetes mellitus have been generated in the large-scale Munich ENU (N-ethyl-N-nitrosourea) mouse mutagenesis project. The aim of this study was to identify the causal mutation of one of these strains and to characterize the resulting diabetic phenotype. Mutants exhibit a T to G transversion mutation at nt 629 in the glucokinase (Gck) gene, leading to an amino acid exchange from methionine to arginine at position 210. Adult Munich Gck(M210R) mutant mice demonstrated a significant reduction of hepatic glucokinase enzyme activity but equal glucokinase mRNA and protein abundances. While homozygous mutant mice exhibited growth retardation and died soon after birth in consequence of severe hyperglycemia, heterozygous mutant mice displayed only slightly elevated blood glucose levels, present from birth, with development of disturbed glucose tolerance and glucose-induced insulin secretion. Additionally, insulin sensitivity and fasting serum insulin levels were slightly reduced in male mutant mice from an age of 90 days onward. While beta-cell mass was unaltered in neonate heterozygous and homozygous mutant mice, the total islet and beta-cell volumes and the total volume of isolated beta-cells were significantly decreased in 210-day-old male, but not female heterozygous mutant mice despite undetectable apoptosis. These findings indicate that reduced total islet and beta-cell volumes of male mutants might emerge from disturbed postnatal islet neogenesis. Considering the lack of knowledge about the pathomorphology of maturity-onset diabetes of the young type 2 (MODY 2), this glucokinase mutant model of reduced total islet and total beta-cell volume provides the opportunity to elucidate the impact of a defective glucokinase on development and maintenance of beta-cell mass and its relevance in MODY 2 patients.

[Solitary liver tumor as a manifestation of polyarteritis nodosa]

HISTORY

A 65-year-old female was admitted with fever of unknown origin.

DIAGNOSTIC PROCEDURES

Abdominal computed tomography showed a solid mass (7.5 cm in diameter) with central fluid, located in the right lobe of the liver. Fine-needle aspiration cytology was unremarkable. Further work-up procedures for suspected liver abscess included colonoscopy, which surprisingly revealed adenocarcinoma at 13 cm from the anal orifice.

THERAPY AND CLINICAL COURSE

Both lesions in the rectum and liver were resected. While a moderately differentiated (G2) adenocarcinoma of the rectosigmoid junction (stage T3/ N0) was confirmed, histology of the hepatic mass showed liver infarction due to polyarteritis nodosa of the medium-sized arteries. Treatment with 20 mg/d prednisolone was initiated and tapered off over the next three months. The clinical course after discontinuation of corticosteroids was unremarkable over a 6-month follow-up.

CONCLUSION

It is suggested that polyarteritis nodosa of the liver occurred in this patient as a paraneoplastic phenomenon and subsided after resection of colorectal cancer and short-term immunosuppression with prednisolone.

[Malignant neoplasms and kidney transplantation]

Together with cardiovascular disorders and metabolic changes, malignant diseases are considered as great challenges in clinical transplantation. As far as long-term function of transplanted organs is concerned, an impact of malignancies is obvious. However, it is important to distinguish between neoplastic disease originating from preexisting lesions in the transplanted organs and de novo graft tumors. Further, there is also a high risk of developing malignant disease during the dialysis, likely due to potential harmful metabolic changes associated with this procedure. After curative management of tumors in such patients, an interval of 2 years for surveillance should be adhered to before patients are put back on the waiting list. The overall risk of transmission of a malignant disease with the transplanted graft has been considered to be as low as <0.2%. In this context, and considering the continual shortage of donated organs, there is an international consensus about the use of kidney grafts with a history of small tumors (<2 cm in diameter und low-grade, i.e., G1). However, the lesions should have been removed with subsequent histopathologic characterization before the acceptance of the organ for transplantation. Early diagnosis and management of de novo malignant disease in transplant patients is crucial for the prognosis of graft function and patient survival. Genitourinary malignancies are frequent among de novo malignancies in transplanted patients. Thus, there is a need for clearly structured concepts for screening of transplant patients in order to detect early malignancies. The incidence of malignant disease correlates directly with the extent of immunosuppression in patients with end-stage renal disease (ESRD) on dialysis, as well as after transplantation with life-long immunosuppressant therapy. In addition, also geographic factors seem to play a role in the differential incidence of tumors among different populations. For instance, the highest incidence of malignancies among immunosuppressed patients has been observed in Australia followed by the USA and Europe. This might be due to the high incidence of de novo skin cancer, which has been linked to the extent of UV exposure.