Real-Time Live Confocal Fluorescence Microscopy as a New Tool for Assessing Platelet Vitality

BACKGROUND: Assessment of platelet vitality is important for patients presenting with inherited or acquired disorders of platelet function and for quality assessment of platelet concentrates. METHODS: Herein we combined live stains with intra-vital confocal fluorescence microscopy in order to obtain an imaging method that allows fast and accurate assessment of platelet vitality. Three fluorescent dyes, FITC-coupled wheat germ agglutinin (WGA), tetramethylrhodamine methyl ester perchlorate (TMRM) and acetoxymethylester (Rhod-2), were used to assess platelet morphology, mitochondrial activity and intra-platelet calcium levels. Microscopy was performed with a microlens-enhanced Nipkow spinning disk-based system allowing live confocal imaging. RESULTS: Comparison of ten samples of donor platelets collected before apheresis and platelets collected on days 5 and 7 of storage showed an increase in the percentage of Rhod-2-positive platelets from 3.6 to 47 and finally to 71%. Mitochondrial potential was demonstrated in 95.4% of donor platelets and in 92.5% of platelets stored for 7 days. CONCLUSION: Such fast and accurate visualization of known key parameters of platelet function could be of relevance for studies addressing the quality of platelets after storage and additional manipulation, such as pathogen inactivation, as well as for the analysis of inherited platelet function disorders.

[Primary hyperparathyroidism. Postoperative normocalcemic hyperparathyrinemia after curative parathyroidectomy]

INTRODUCTION

Normocalcemic hyperparathyrinemia, i.e. elevated parathyroid hormone (PTH) levels after parathyroidectomy in patients with primary hyperparathyroidism (pHPT) may occur in the course of postoperative recovery without the development of persistence or relapse.

MATERIALS, METHODS AND RESULTS

Intraoperative and long-term (7 year) postoperative PTH and calcium levels after curative parathyroidectomy are demonstrated on the basis of a case report of a 62-year-old female patient with severe pHPT and pronounced osseous and renal manifestations. The intraoperative PTH gradient displayed a decrease from 1072 pg/ml to 13 pg/ml (normal range 11-67 pg/ml) followed by an increase of up to 287 pg/ml. The hyperparathyoid values decline to subnormal levels on administration of calcium and vitamin D and increase again after tapering these medications. The inverse calcium/PTH correlation in the course of the 7-year observation period suggests an intact feed-back mechanism. Preoperative PTH screening was performed in 316 consecutive normocalcemic thyroid patients to evaluate the rate of incidental hyperparathyroidism in patients with normal serum calcium levels. Of these patients 31 (9.8%) with normocalcemia (average 2.28 mmol/l, normal range 2.1-2.7 mmol/l) exhibited increased PTH levels averaging 84.2 pg/ml. A parathyroid adenoma was found intraoperatively as the cause for normocalcemic pHPT in only 1 of these 31 patients.

DISCUSSION AND CONCLUSIONS

A review of the literature revealed that late postoperative elevated parathyroid hormone levels after successful pHPT surgery occur in 21.5%. Multiple causes are discussed, e.g. reactive hyperparathyroidism in cases of relative hypocalcemia, hungry bone syndrome, vitamin D deficiency, renal dysfunction and ethnic or lifestyle differences. In mild cases of postoperative hyperparathyrinemia observation of the patient may be sufficient. In cases of reactive hyperparathyroidism due to hypocalcemia, administration of calcium is indicated, in symptomatic patients, additional administration of vitamin D or calcitriol is necessary. Vitamin D deficiency per se needs adequate substitution. In cases of ongoing hyperparathyrinemia an interdisciplinary diagnostic and therapeutic approach is required.

Identification of the gene encoding alkylglycerol monooxygenase defines a third class of tetrahydrobiopterin-dependent enzymes

Alkylglycerol monooxygenase (glyceryl-ether monooxygenase, EC 1.14.16.5) is the only enzyme known to cleave the O-alkyl bond of ether lipids which are essential components of brain membranes, protect the eye from cataract, interfere or mediate signalling processes, and are required for spermatogenesis. Along with phenylalanine hydroxylase, tyrosine hydroxylase, tryptophan hydroxylase, and nitric oxide synthase, alkylglycerol monooxygenase is one of five known enzymatic reactions which depend on tetrahydrobiopterin. Although first described in 1964, no sequence had been assigned to this enzyme so far since it lost activity upon protein purification attempts. A functional library screen using pools of plasmids of a rat liver expression library transfected to CHO cells was also unsuccessful. We therefore selected human candidate genes by bioinformatic approaches and by proteomic analysis of partially purified enzyme and tested alkylglycerol monooxygenase activity in CHO cells transfected with expression plasmids. Transmembrane protein 195, a predicted membrane protein with unassigned function which occurs in bilateral animals, was found to encode for tetrahydrobiopterin-dependent alkylglycerol monooxygenase. This sequence assignment was confirmed by injection of transmembrane protein 195 cRNA into Xenopus laevis oocytes. Transmembrane protein 195 shows no sequence homology to aromatic amino acid hydroxylases or nitric oxide synthases, but contains the fatty acid hydroxylase motif. This motif is found in enzymes which contain a diiron center and which carry out hydroxylations of lipids at aliphatic carbon atoms like alkylglycerol monooxygenase. This sequence assignment suggests that alkylglycerol monooxygenase forms a distinct third group among tetrahydrobiopterin-dependent enzymes.

Improved agar bottle plate for isolation of methanogens or other anaerobes in a defined gas atmosphere

A bottle plate for the cultivation of methanogens or other organisms in a defined pressurized-gas atmosphere was developed. The bottle provides the convenience of an agar streak plate, solves the problem of the water exudate from agar medium, and provides a convenient way of adding or sampling a defined gas atmosphere.

Langerhans cells and dermal dendritic cells capture protein antigens in the skin: possible targets for vaccination through the skin

Dendritic cells capture and process antigen and present it to T lymphocytes in the lymphoid organs. Dendritic cells of the skin, including epidermal Langerhans cells, langerin(+) and langerin(negative) dermal dendritic cells are ideally positioned to take up pathogens that enter the body through the skin or vaccines that are administered into (intradermal) or onto (epicutaneous) the skin. The antigen uptake properties of skin dendritic cells have not thoroughly been studied yet. We therefore investigated the uptake of the fluorochrome-conjugated model antigen ovalbumin (OVA) by skin dendritic cells in the mouse. OVA was readily taken up by immature Langerhans cells both in situ and in cell suspensions. When offered to Langerhans cells in situ either by "bathing" skin explants in OVA-containing culture medium or by intradermal injection they retained the captured OVA for at least 2-3 days when migrating into the culture medium and, importantly, into the draining lymph nodes. Also langerin(+) and - to a larger extent - langerin(negative) skin dendritic cells took up and transported OVA to the lymph nodes. Interestingly, mature Langerhans cells were still capable of ingesting substantial amounts of OVA, indicating that predominantly receptor-mediated endocytosis is operative in these cells. Unlike macropinocytosis, this pathway of endocytosis is not shut down upon dendritic cell maturation. These observations indicate that in intradermal vaccination schemes, Langerhans cells from the epidermis are prominently involved. They were recently shown to possess the capacity to induce functional cytotoxic T lymphocytes. Furthermore, the potential to markedly enhance antigen uptake and processing by targeting antigen to c-type lectin receptors on Langerhans cells was also recently demonstrated. Our data provide a rationale and an incentive to explore in more detail antigen targeting to Langerhans cells with the aim of harnessing it for immunotherapy.

Tetrahydrobiopterin protects the kidney from ischemia-reperfusion injury

Tetrahydrobiopterin (BH4) is an essential cofactor for the nitric oxide (NO) synthases and represents a critical determinant of NO production. BH4 depletion during ischemia leads to the uncoupling of the synthases, thus contributing to reperfusion injury due to increased superoxide formation. To examine whether BH4 supplementation attenuates ischemia-reperfusion injury, we clamped the left renal arteries of male Lewis rats immediately following right-side nephrectomy. BH4 tissue levels significantly decreased after 45 min of warm ischemia compared with levels in non-ischemic controls. Histopathology demonstrated significant tubular damage and increased peroxynitrite formation. Intravital fluorescent microscopy found perfusion deficits in the microvasculature and leakage of the capillary mesh. Supplemental BH4 treatment before ischemia significantly reduced ischemia-induced renal dysfunction, and decreased tubular histologic injury scores and peroxynitrite generation. BH4 also significantly improved microcirculatory parameters such as functional capillary density and diameter. These protective effects of BH4 on microvasculature were significantly correlated with its ability to abolish peroxynitrite formation. We suggest that BH4 significantly protects against acute renal failure following ischemia reperfusion. Whether BH4 has a therapeutic potential will require more direct testing in humans.

Clinical presentation and molecular pathophysiology of autosomal dominant hemochromatosis caused by a novel ferroportin mutation

Mutations in the SLC40A1 gene, which encodes ferroportin, are associated with autosomal dominant hemochromatosis. Ferroportin is inhibited directly by hepcidin, a key iron-regulatory peptide, and functional consequences of SLC40A1 mutations account for observed phenotypic differences in patients with ferroportin disease. We describe a large pedigree with a novel SLC40A1 mutation and, through in vitro analysis, elucidate the associated molecular mechanism of iron overload. The entire coding sequence of the SLC40A1 gene was sequenced in a pedigree, presenting with autosomal dominant hyperferritinemia. The functional effects of a novel SLC40A1 mutation were studied by overexpression of wild-type and mutant ferroportin fusion proteins in human embryonic kidney cells. Iron export was studied in these cells using (59)Fe transport assays; subcellular localization of ferroportin was examined by way of confocal microscopy. A novel SLC40A1 mutation p.R489K segregated with iron overload in a family with clinical and histopathological signs of macrophage-type ferroportin disease. Human embryonic kidney cells overexpressing p.R489K ferroportin showed decreased iron export capacity when compared with wild-type ferroportin overexpressing cells. Subcellular localization studies demonstrated that p.R489K ferroportin was retained abnormally within an intracellular compartment.

CONCLUSION

We report a novel pathological SLC40A1 variant associated with abnormal cell surface expression of ferroportin due to intracellular retention of the mutant protein. These findings predict macrophage-type ferroportin disease, the phenotype observed in this kindred. Study of the molecular cell biology of ferroportin and its mutants is key to understanding the pathogenesis of this increasingly recognized form of hemochromatosis, which responds poorly to conventional therapy.

Intraoperatively salvaged red blood cells contain nearly no functionally active platelets, but exhibit formation of microparticles: results of a pilot study in orthopedic patients

BACKGROUND

Previous data show improved clot formation after retransfusion of salvaged red blood cells (RBCs). This study was conducted to explore whether such RBCs contain clinically relevant numbers of active residual platelets (PLTs) or exhibit formation of microparticles (MPs).

STUDY DESIGN AND METHODS

Thirteen patients undergoing major orthopedic surgery were included in the study, and arterial blood samples from patients and samples from the retransfusion bag were analyzed with various PLT function tests and flow cytometry.

RESULTS

With commercial blood cell counters, the numbers of PLTs in the RBC unit were reduced to approximately 25% compared to patients' blood. In contrast, results from flow cytometry showed an 11- to 945-fold reduction in median counts referring to total PLTs and free PLTs. Interestingly, smaller quantities of PLT-derived MPs were found in samples from the retransfusion bag than in patients' arterial blood. Conversely, RBC- and white blood cell-derived MP counts were increased in the retransfusion bag compared to the patient. Rotational thrombelastometry and the Impact-R system (DiaMed) showed a pronounced impairment of PLT ability with regard to adhesion, aggregation, and clot formation. With the use of confocal microscopy, only a few free thrombocytes were detectable among the huge numbers of RBCs.

CONCLUSION

Only few free and thus active PLTs are detectable in processed RBCs. It seems very unlikely that these few PLTs can improve clot strength. Nevertheless, the impact of the detected MPs on thrombin generation needs to be clarified in further studies.

Identification of a novel CYP2C19-mediated metabolic pathway of S-citalopram in vitro

Systemic exposure of the antidepressant S-citalopram (escitalopram, SCIT) differs several-fold according to variable cytochrome P450 2C19 activity, demonstrating the importance of this enzyme for the metabolic clearance of SCIT in vivo. However, previous studies have indicated that the involvement of CYP2C19 in formation of the metabolite N-desmethyl S-citalopram (SDCIT) is limited. Therefore, the purpose of the present in vitro study was to investigate to what extent the CYP2C19-mediated clearance of SCIT was due to a metabolic pathway different from N-desmethylation and to identify the product(s) of this possible alternative metabolic reaction. CYP2C19-mediated metabolism of SCIT was investigated using recombinant Supersomes expressing human CYP2C19. Initial experiments showed that approximately half of the CYP2C19-mediated clearance of SCIT was accounted for by the N-desmethylation pathway. Subsequent experiments identified that, in addition to SDCIT, the propionic acid metabolite of SCIT (SCIT PROP) was formed by CYP2C19 in vitro. Formation of SCIT PROP accounted for 35% of total CYP2C19-mediated clearance of SCIT (calculated as the ratio between metabolite formation rate and substrate concentration at low substrate concentration). Moreover, analysis of samples from six CYP2C19-genotyped patients treated with SCIT indicated that differences in serum concentrations of SCIT between CYP2C19 genotypes may be due to a combined effect on SCIT PROP and SDCIT formation. Identification of SCIT PROP as a metabolic pathway catalyzed by CYP2C19 might explain why impaired CYP2C19 activity has a substantially larger effect on SCIT exposure than estimated from in vitro data based solely on formation of SDCIT.

The SUMO-E3 ligase PIAS3 targets pyruvate kinase M2

Pyruvate kinase M2 (M2-PK) controls the rate-limiting step at the end of the glycolytic pathway in normal proliferating and tumor cells. Other functions of M2-PK in addition to its role in glycolysis are little understood. The aim of this study was to identify new cellular interaction partners of M2-PK in order to discover novel links between M2-PK and cellular functions. Here we show that the SUMO-E3 ligase protein PIAS3 (inhibitor of activated STAT3) physically interacts with M2-PK and its isoenzyme M1-PK. Moreover, we demonstrate that endogenous SUMO-1-M2-PK conjugates exist in mammalian cells. Furthermore, we show that transient expression of PIAS3 but not the RING domain mutant PIAS3 (C299S, H301A) is consistent with nuclear localization of M2-PK and PIAS3 and M2-PK partially co-localize in the nucleus of these cells. This study suggests a link between PIAS3 and nuclear pyruvate kinase.

Dkk-3 expression in the tumor endothelium: a novel prognostic marker of pancreatic adenocarcinomas

Dkk-3 is proposed to be a new specific marker for tumor endothelial cells. Here we analyzed the clinical relevance of Dkk-3 expression in pancreas adenocarcinomas and determined its role on endothelial cell growth in vitro. Microvessel density in tumor samples was immunohistochemically determined using Dkk-3 and CD31 as endothelial cell markers, respectively. Based on the median microvessel density as a cut-off point, patients were categorized into high and low microvessel density groups and a correlation with survival and clinical parameters was assessed. Moreover, the role of Dkk-3 expression on chemosensitivity of endothelial cells was analyzed. In contrast to CD31 staining, Dkk-3-positive vessels were found only in tumor tissue and Dkk-3 microvessel density significantly correlated negative with tumor grading. In survival analysis the median survival time was 7 months for patients with Dkk-3 low, and 15 months for Dkk-3 high microvessel density (P = 0.0013). Subset analysis of patients receiving gemcitabine therapy showed that overall survival was significantly decreased in Dkk-3 low tumors than in high tumors (P = 0.009). In Cox regression Dkk-3 emerged as a significant independent parameter (P = 0.024). Dkk-3 overexpression in endothelial cells resulted in significantly enhanced growth inhibition after 5-fluorouracil or gemcitabine treatment compared to control endothelial cells and cancer cell lines. Dkk-3 low microvessel density was associated with tumor progression and worse clinical outcome. Overexpression of Dkk-3 enhanced endothelial cell growth inhibition to chemotherapeutic drugs. Therefore, we suggest that Dkk-3 high microvessel density may help to select patients who may benefit from chemotherapy.

The cell-type specificity of mitochondrial dynamics

Recent advances in mitochondrial imaging have revealed that in many cells mitochondria can be highly dynamic. They can undergo fission/fusion processes modulated by various mitochondria-associated proteins and also by conformational transitions in the inner mitochondrial membrane. Moreover, precise mitochondrial distribution can be achieved by their movement along the cytoskeleton, recruiting various connector and motor proteins. Such movement is evident in various cell types ranging from yeast to mammalian cells and serves to direct mitochondria to cellular regions of high ATP demand or to transport mitochondria destined for elimination. Existing data also demonstrate that many aspects of mitochondrial dynamics, morphology, regulation and intracellular organization can be cell type-/tissue-specific. In many cells like neurons, pancreatic cells, HL-1 cells, etc., complex dynamics of mitochondria include fission, fusion, small oscillatory movements of mitochondria, larger movements like filament extension, retraction, fast branching in the mitochondrial network and rapid long-distance intracellular translocation of single mitochondria. Alternatively, mitochondria can be rather fixed in other cells and tissues like adult cardiomyocytes or skeletal muscles with a very regular organelle organization between myofibrils, providing the bioenergetic basis for contraction. Adult cardiac cells show no displacement of mitochondria with only very small-amplitude rapid vibrations, demonstrating remarkable, cell type-dependent differences in the dynamics and spatial arrangement of mitochondria. These variations and the cell-type specificity of mitochondrial dynamics could be related to specific cellular functions and demands, also indicating a significant role of integrations of mitochondria with other intracellular systems like the cytoskeleton, nucleus and endoplasmic reticulum (ER).

Complex patterns of mitochondrial dynamics in human pancreatic cells revealed by fluorescent confocal imaging

Mitochondrial morphology and intracellular organization are tightly controlled by the processes of mitochondrial fission-fusion. Moreover, mitochondrial movement and redistribution provide a local ATP supply at cellular sites of particular demands. Here we analysed mitochondrial dynamics in isolated primary human pancreatic cells. Using real time confocal microscopy and mitochondria-specific fluorescent probes tetramethylrhodamine methyl ester and MitoTracker Green we documented complex and novel patterns of spatial and temporal organization of mitochondria, mitochondrial morphology and motility. The most commonly observed types of mitochondrial dynamics were (i) fast fission and fusion; (ii) small oscillating movements of the mitochondrial network; (iii) larger movements, including filament extension, retraction, fast (0.1-0.3 mum/sec.) and frequent oscillating (back and forth) branching in the mitochondrial network; (iv) as well as combinations of these actions and (v) long-distance intracellular translocation of single spherical mitochondria or separated mitochondrial filaments with velocity up to 0.5 mum/sec. Moreover, we show here for the first time, a formation of unusual mitochondrial shapes like rings, loops, and astonishingly even knots created from one or more mitochondrial filaments. These data demonstrate the presence of extensive heterogeneity in mitochondrial morphology and dynamics in living cells under primary culture conditions. In summary, this study reports new patterns of morphological changes and dynamic motion of mitochondria in human pancreatic cells, suggesting an important role of integrations of mitochondria with other intracellular structures and systems.

Kinetics of serum parathyroid hormone during and after thyroid surgery

Background

Hypocalcaemia after thyroidectomy is thought to result from surgical damage to the parathyroid glands. This study analysed postoperative outcomes related to perioperative parathyroid hormone (PTH) levels.

Methods

Some 402 consecutive patients undergoing thyroid surgery were studied prospectively to monitor perioperative changes in serum PTH and Ca2+ levels, and clinical symptoms of hypocalcaemia.

Results

Transient symptomatic hypocalcaemia and persistent hypoparathyroidism occurred in 61 (15 per cent) and six (1·5 per cent) of 402 patients respectively. The intraoperative decline in PTH was 20·2 per cent; the trough (63·8 per cent of preoperative value) was reached 3 h after surgery. Before surgery, PTH levels were correlated inversely with serum Ca2+ concentration. The correlation remained positive from 3 h after surgery until postoperative day 14. Thus, PTH secretion was reduced, but remained sufficient to prevent symptomatic hypocalcaemia in most patients. A low serum PTH level was predictive of persistent hypoparathyroidism (sensitivity and negative predictive value 100 per cent, but poor specificity of 54·1 per cent).

Conclusion

Thyroid surgery impairs hormone secretion by the parathyroid glands resulting in postoperative latent parathyroid insufficiency. Normal PTH levels 3 h after surgery and a normal serum calcium level on the first postoperative day rule out persistent hypoparathyroidism.

Cytoplasmic signaling in the control of mitochondrial uproar?

The concept of a pre-emptive strike as a good means to prevent greater harm may be frequently over-stressed in daily life. However, biological systems in a homeostatic balance are prepared to withstand a certain degree of hostile fire by rather passive means. This also applies to the maintenance of cell survival, where a plethora of protective proteins provide safeguard against erroneous activation of death pathways. Apart from these mechanisms active processes are also essential for the maintenance of cellular homeostasis, commonly referred to as survival signaling. Frequently their targets may be mitochondrial, assuring organelle integrity, which is essential for continued energy production and survival. Transient or permanent failures in these cellular defense strategies result in pathophysiological conditions, which manifest themselves e.g. as cancer or ischemia/reperfusion-associated organ damage.

The surface properties of nanocrystalline diamond and nanoparticulate diamond powder and their suitability as cell growth support surfaces

Nanocrystalline diamond (NCD) films and nanoparticulate diamond powder (DP) are the two main representatives of diamond at the nanoscale. This study was designed to investigate the suitability of these biomaterials as cell growth supports and to determine surface characteristic properties best suited to cell attachment and proliferation. Surface topography, chemical termination and wetting properties of NCD- and DP-coated borosilicate glass substrates were correlated to attachment, proliferation and differentially regulated gene expression of human renal epithelial cells (HK-2 cell line) cultured on these surfaces. Hydrogen-terminated NCD (NCD-H) surfaces were shown to inhibit cell attachment, which indicates that the lack of functional polar groups prevents adherent cells from settling on a surface, whether nanostructured or not. In contrast to NCD-H, oxygen-terminated NCD (NCD-O) as well as DP surfaces demonstrated improved cell attachment, as compared to borosilicate glass, which is a commonly used material for cell growth supports. NCD-O not only revealed an increased cell attachment, but also a markedly increased proliferation rate. Finally, none of the investigated surface modifications appeared to cause adverse cellular reactions or markedly alter cellular phenotype.

Functional capillary density in ischemic conditioning: implications for esophageal resection with the gastric conduit

BACKGROUND

Ischemia may lead to leakage at the esophagogastric anastomosis after esophagectomy. The aim of this study was to investigate time dependent changes of gastric microcirculation after ischemic conditioning.

METHODS

Twenty male Lewis rats were used and analyzed in 3 study groups and 1 control group. Group 1 (n = 5) underwent ligation of the left gastric artery and intravital fluorescence microscopy (IVM) on day 0; group 2 (n = 5) underwent IVM at 28 days after ligation of the LGA; and group 3 (n = 5) underwent IVM at 56 days after ligation of the LGA. The controls (n = 5) underwent sham surgery and IVM at 28 days thereafter. IVM was used to analyze gastric microcirculation by means of functional capillary density.

RESULTS

Ligation of the LGA immediately led to significant reduction of perfusion at the lesser (100.5 +/- 3.1 microm/mm(2) vs 220.4 +/- 7.4 microm/mm(2); P <.001) and greater curvatures (195.1 +/- 7.9 microm/mm(2) vs 234.1 +/- 9.4 microm/mm(2); P = .013). During 28 days, microcirculation at the lesser curve ameliorated (164.9 +/- 12.8 microm/mm(2)) and reached normal values after 56 days (215.8 +/- 7.4 microm/mm(2)). At the greater curve, microcirculation was improved during 4 (261.3 +/- 8 microm/mm(2)P = .039) and 8 weeks (317.9 +/- 10.3 microm/mm(2); P <.001 vs control).

CONCLUSIONS

Gastric microperfusion continuously improves after partial devascularization. The results support further clinical studies to optimize gastric ischemic conditioning in patients undergoing esophagectomy.

Dysregulation of Dkk-3 expression in benign and malignant prostatic tissue

BACKGROUND

The Dickkopf (Dkk) family comprises four members Dkk-1, -2, -3, and -4. Dkk-3, the most divergent family member, unlike the others does not modulate Wnt signaling. Dkk-3 is proposed to function as a secreted tumor suppressor since it is downregulated in a number of cancer cells and prostate cancer tissue and thus may be a promising candidate molecule for therapeutic interference.

METHODS

The in situ tissue localization of Dkk-3 protein in normal prostate (NP), benign prostatic hyperplasia (BPH), and prostate carcinoma (PCa) was investigated by immunohistochemistry (IHC)/immunofluorescence. In addition, biological function of Dkk-3 in terms of proliferation and viability was evaluated in primary prostate basal epithelial cells (PrEC), stromal cells (PrSC), and established human PCa cell lines by treatment with recombinant protein or by overexpression.

RESULTS

Stimulation with purified recombinant protein and overexpression of Dkk-3 did not significantly alter in vitro cell proliferation in any primary or tumor cell line evaluated. Dkk-3 was expressed in both the basal and secretory epithelium of NP. In BPH expression was restricted to defined basal cells and was absent in tumor cells of high grade PCa. In contrast to normal prostatic tissue, Dkk-3 was upregulated in subglandular blood vessels of BPH and in the reactive stroma of PCa tissue.

CONCLUSIONS

Our results indicate that Dkk-3 expression in the normal epithelium of the prostate is lost during benign and malignant transformation and differentiation processes. The loss of expression seems to be counterbalanced by upregulation of Dkk-3 expression in the blood vessels of the remodeled tissue.

Serum concentrations of venlafaxine and its metabolites O-desmethylvenlafaxine and N-desmethylvenlafaxine in heterozygous carriers of the CYP2D6*3, *4 or *5 allele

OBJECTIVE

Increased systemic exposure of the antidepressant venlafaxine and increased risk of side effects has previously been observed in patients with defective CYP2D6 function [poor metabolisers (PMs)]. The aim of this study was to evaluate venlafaxine pharmacokinetics in carriers of one functional and one defective CYP2D6 allele [heterozygous extensive metabolisers (HEMs)].

METHODS

Data was collected retrospectively from a therapeutic drug-monitoring database. All CYP-genotyped patients with steady-state serum concentration measurements of venlafaxine and metabolites were included in the study. Patients were divided in groups: *1/*1 [homozygous extensive metabolisers (EMs)], *1/*3, *4 or *5 (HEMs) and *4/*4 (PMs). Dose-adjusted serum concentrations of venlafaxine, O-desmethylvenlafaxine, N-desmethylvenlafaxine, and the metabolic ratio (O-desmethylvenlafaxine/venlafaxine) were compared between the different genotype groups.

RESULTS

The sum of venlafaxine and O-desmethylvenlafaxine serum concentrations was not significantly different between genotype groups. Metabolic ratio was 50% lower in HEMs (n = 18) than in EMs (n = 20) (p < 0.05). Serum concentration of N-desmethylvenlafaxine was 5.5-fold higher in HEMs (p < 0.01) and 22-fold higher in PMs (p < 0.001) than in EMs.

CONCLUSION

The study showed a shift in the metabolic pathway resulting in substantially higher levels of N-desmethylvenlafaxine in HEMs than in EMs. The metabolic pattern of venlafaxine in HEMs was similar to previous observations in PMs and possibly represents an increased risk of venlafaxine-related side effects in HEM patients.

Direct detection of formaldehyde in air by a novel NAD+- and glutathione-independent formaldehyde dehydrogenase-based biosensor

An amperometric enzyme-based sensor-system for the direct detection of formaldehyde in air is under investigation. The biosensor is based on a native bacterial NAD(+)- and glutathione-independent formaldehyde dehydrogenase as biorecognition element. The enzyme was isolated from Hyphomicrobium zavarzinii strain ZV 580, grown on methylamine hydrochloride in a fed-batch process. The sensor depends on the enzymatic conversion of the analyte to formic acid. Released electrons are detected in an amperometric measurement at 0.2V vs. Ag/AgCl reference electrode by means of a redox-mediator. To optimize the sensing device, Ca(2+) and pyrroloquinoline quinone (PQQ) were added to the buffer solution as reconstitutional substances. At this stage, the sensor shows linear response in the tested ppm-range with a sensitivity of 0.39 microA/ppm. The signal is highly reproducible with respect to sensitivity and base line signal. Reproducibility of sensitivity is more than 90% within the same bacterial batch and even when enzyme of different bacterial batches is used.

Molecular and cellular key players in human islet transplantation

Human islet transplantation could represent an attractive alternative to insulin injections for the treatment of diabetes type 1. However, such an approach requires a better understanding of the molecular and cellular switches controlling β-cell function in general as well as after transplantation into the liver. Although much research has been done into the suitability of stem or progenitor cells to generate a limitless supply of human β-cells, a reproducible and efficient protocol for the differentiation of such cells into stably insulin-secreting β-cells suitable for transplantation has yet to be reported. Fueled by recent findings showing that mature β-cells are able to regenerate, many efforts have been undertaken to expand this cell pool. Unfortunately, also these approaches had problems to yield sufficiently differentiated human islet cells. The aim of this review is to summarize recent findings describing some of the molecular and cellular key players of islet biology. A more complete understanding of their orchestration and the use of new methods such as real time confocal imaging for the assessment of islet quality may yield the necessary advancements for more successful human islet transplantation.

Development of a Novel Perfused Rotary Cell Culture System

A rotary cell culture system has been established. System quality was determined by observing the stability of the basic parameters of temperature, gas exchange, and pH, and mass transfer (time to equimolarity) between the medium circuit and the 2 cell-containing chambers was investigated. Mass transfer time for urea and several ions was approximately 30 min for the high-fiber-density chamber (HFC) and 50 min for the low-fiber-density chamber (LFC). Exchange of albumin was delayed in both chambers, highlighting the dependence of mass transfer on area of exchange and molecule size. Finally, the ability for cell growth and maintenance was tested. Densities of up to 1.2 x 10(7) immortalized cells per mL at a viability of up to 85% were obtained after 1 week of continuous, non-interfering culture of immortalized cells in the HFC. Human pancreatic islets were also cultivated in the LFC. Confocal analysis using fluorescent dyes showed that the 3-dimensional islet structure was maintained for 1 week. Promising results were obtained, which will further our ongoing efforts toward establishing a mobile cell culture system.

Bilirubin inhibits tumor cell growth via activation of ERK

Bilirubin for decades was considered a potentially toxic waste product of heme degradation until the discovery that it is a potent antioxidant. Accumulating data from observations in humans and experimental studies indicate that the bile pigment may be protective against certain diseases. Based on our own observations that bilirubin induces cell cycle arrest in abnormally proliferating vascular smooth muscle cells and clinical observations describing a lesser incidence of cancer in healthy individuals with high normal or slightly elevated serum bilirubin levels, we hypothesized that bilirubin might suppress tumor cell proliferation in vitro and in vivo. As possible effectors we analyzed key proteins that are involved in cell cycle progression and apoptosis. In vivo, tumor growth was assessed in BALB/c nude mice bearing HRT-18 colon cancer xenografts that were treated with bilirubin. In vitro, we investigated the effect of bilirubin on various cell lines and the signaling pathways involved in bilirubin action on tumor cell proliferation in HRT-18 cells using western blots. Bilirubin potently inhibited tumor cell proliferation in vivo and acted cytostatic and pro-apoptotic in vitro. The signaling cascades responsible for this action involved induction of p53, p27, hypophosphorylation of the retinoblastoma tumor suppressor protein as well as caspase activation. These effects were dependent on ERK 1/2. Our study demonstrates that bilirubin may play a role in the defense against cancer by interfering with pro-cancerogenic signaling pathways.

Septischer Schock mit Niereninsuffizienz und Hautmanifestationen als Komplikation einer Salmonella-enteritidis-Infektion

Infections by Salmonella enteritidis commonly present with diarrhoea, vomiting and fever and complications such as septicaemia, pleural effusion and acute renal failure are usually rare. There are only few reports of cutaneous manifestations and especially septic shock in patients with Salmonella enteritidis infection. We report on a previously healthy seven-year-old boy suffering from Salmonella enteritidis septicaemia presenting with septic shock, pleural effusion, renal failure and an unusual maculopapular skin eruption on both wrists and ankles. The boy had no underlying immunodeficiency.

Impact of the Ultrarapid CYP2C19*17 Allele on Serum Concentration of Escitalopram in Psychiatric Patients

Recently, a novel allelic variant of cytochrome P450 2C19 encoding ultrarapid enzyme activity was described (denoted CYP2C19*17). The objective of this study was to evaluate the impact of CYP2C19*17 on serum concentration of escitalopram in psychiatric patients. One hundred and sixty-six patients treated with escitalopram were divided into the following subgroups according to CYP2C19 genotype: CYP2C19*17/*17 (n=7), CYP2C19*1/*17 (n=43), CYP2C19*1/*1 (n=60), CYP2C19*17/def (n=16), CYP2C19*1/def (n=34), and CYP2C19def/def (n=6) (def=defective allele, i.e., CYP2C19*2 or *3). Dose-adjusted serum concentrations of escitalopram were compared using the CYP2C19*1/*1 subgroup as reference. Geometric mean of the escitalopram serum concentration was 42% lower in patients homozygous for CYP2C19*17 (P<0.01) and 5.7-fold higher in subjects homozygous for defective CYP2C19 alleles (P<0.001). Of the heterozygous subgroups, only CYP2C19*1/def was significantly different from CYP2C19*1/*1 (P<0.001). In conclusion, a homozygous CYP2C19*17 genotype is associated with lower serum concentration of escitalopram, which might imply increased risk of therapeutic failure.

Effect of sorafenib in symptomatic metastatic medullary thyroid cancer

14065

Background: RET receptor tyrosin kinase activity plays a major role in medullary thyroid cancer (MTC) tumor growth. Sorafenib is an oral agent that selectively targets RET tyrosine kinases. Methods: 5 patients (pts) with metastatic MTC with excessive elevation of calcitonin(CTN) serum levels entered this pilotstudy. Hypercalcitonemia-related symptoms were present in all pts (3 severe diarrhea, 2 moderate) and metastasis- related symptoms were present in 4 pts (2 severe pain, 2 moderate). All pts had had prior thyreoidectomy and cervical +- mediastinal lymphnode dissection, 4 pts had prior octreotide therapy, 3 prior chemotherapy. Pts received 800 mg or 400 mg (weight < 50 kg) Sorafenib as a starting dose. According to the protocol, the dose was reduced gradually in 200 mg scale when pts revealed therapy induced side effects to avoid worsening of quality of life. Sorafenib has to be administered at least 3 months, the scheduled duration of therapy was 6 months. Physical examination, calcitonin and CEA levels were monitored every 4 weeks, measurable metastatic lesions were controlled by appropriate means 3 and 6 months after starting therapy. Primary objective was to assess the effect on CTN dependent symptoms, second objectives included assessments of tumor response (RECIST) and biochemical response. Results: After 2–3 months CTN decreased to levels >50% of baseline in all pts, to levels >90% in 2 pts. According to that all pts were free of CTN related symptoms after 4 weeks. In 4 pts CEA levels reacted in a similar way. After 6 months controls of metastatic lesions were classified as CR-1 pt, PR-1 pt, NC-3 pts. 2 pts with severe metastasis-related pain were off analgesics after 3 months of treatment. Due to side effects Sorafenib dosage was reduced to 50% of the initial dose in all patients. Interestingly marked TSH - elevations were observed in 3 pts which indicates a direct influence to the hypothalamic-pituary-axis. Conclusion: Sorafenib has to be considered as an effective teatment of symptomatic, metastatic MTC.

No significant financial relationships to disclose.

Adult neurogenesis in serotonin transporter deficient mice

Serotonin (5-HT) is a regulator of morphogenetic activities during early brain development and neurogenesis, including cell proliferation, migration, differentiation, and synaptogenesis. The 5-HT transporter (5-HTT, SLC6A4) mediates high-affinity reuptake of 5-HT into presynaptic terminals and thereby fine-tunes serotonergic neurotransmission. Inactivation of the 5-HTT gene in mice reduces 5-HT clearance resulting in persistently increased concentrations of synaptic 5-HT. In the present study, we investigated the effects of elevated 5-HT levels on adult neurogenesis in the hippocampus of 5-HTT deficient mice, including stem cell proliferation, survival, and differentiation. Using an in vivo approach, we showed an increase in proliferative capacity of hippocampal adult neural stem cells in aged 5-HTT knockout mice (approximately 14.5 months) compared to wildtype controls. In contrast, in vivo and additional in vitro analyses of younger adult 5-HTT knockout mice (approximately 7 weeks and approximately 3.0 months) did not reveal significant changes in proliferation of neural stem cells or survival of newborn cells. We showed that the cellular fate of newly generated cells in 5-HTT knockout mice is not different with respect to the total number and percentage of neurons or glial cells from wildtype controls. Our findings indicate that elevated synaptic 5-HT concentration throughout early development and later life of 5-HTT deficient mice does not induce adult neurogenesis in adult mice, but that elevated 5-HT levels in aged mice influence stem cell proliferation.

A novel technique for heterotopic vascularized pancreas transplantation in mice to assess ischemia reperfusion injury and graft pancreatitis

BACKGROUND

Although various suture techniques for murine pancreas transplantation have been described, severe limitations have limited their widespread use. We therefore designed a surgical model for cervical heterotopic pancreas transplantation using a cuff technique.

METHODS

C57BL6 mice were used as donor and recipient pairs. Recipients were rendered diabetic with streptozotocin and subsequently transplanted. The donor pancreas was isolated using a no-touch technique and then placed in the recipient's cervical region. Vascular anastomoses were completed by pulling the portal vein over the external jugular vein cuff and the donor aortic segment over the carotid cuff and fixed with an 8-0 ligature thereby facilitating a nonsuture technique. To test applicability of this model, graft microcirculation was evaluated by intravital microscopy after prolonged cold ischemia (16 h).

RESULTS

The immediate success rate was >90%. Donor operation lasted 40 +/- 5 min; dissection of recipient vessels lasted 20 +/- 4 min. Revascularization time was 4 to 6 min, resulting in a total pancreas ischemia time of 33 +/- 6 min. No thromboembolic complications on the cuff side were observed. Preoperative glucose levels were 518 +/- 59 mg/dl and returned to normal by postoperative day 1 (88 +/- 13 mg/dl). Histology on postoperative days 10 and 30 showed almost normal islet cell and acinar architecture of all grafts. In groups with prolonged cold ischemia, graft microcirculation was significantly reduced and paralleled by increased inflammation, interstitial edema, hemorrhage, acinar vacuolization, and focal areas of necrosis compared with nonischemic controls.

CONCLUSIONS

This new model may provide an excellent tool to further investigate the pathophysiology as well as novel therapeutic strategies of preservation, ischemia reperfusion injury, and graft pancreatitis.

Small human hepatocytes in rotary culture for treatment of alcohol addicts? A pilot study

BACKGROUND

Current approaches to support alcohol addict and/or benzodiazepine-treated patients with liver failure include culturing human cells to take over basic metabolic functions for a certain time.

METHODS

Small human hepatocytes (SH) were grown in a rotary cell culture system, and their potential to metabolize alcohol and the benzodiazepines oxazepam and diazepam was evaluated. Control experiments were performed with SV40-immortalized HEP cells and cell respective drug-free media.

RESULTS

Our results show that SH in rotary culture are able to metabolize ethanol in reasonable amounts compared with evaporation controls (p<0.01). Moreover, SH are also able to metabolize oxazepam and diazepam which proves their ability to perform conjugation and the presence of functional cytochrome P450 enzymes. Basic metabolic activities such as glucose consumption, albumin and urea production are not significantly influenced by the drugs used, which is a precondition for clinical use of these cells. Significantly increased lactate dehydrogenase release indicates enhanced cell death in cultures of SH incubated with either ethanol (p<0.05) or diazepam (p<0.005), but stable viability at or above 90% suggests that cell proliferation is able to keep up with drug-induced cell death.

CONCLUSION

Our preliminary study provides evidence that SH are basically suited to support alcohol-abusing and/or benzodiazepine-treated patients undergoing liver failure.