Changes in connexin 43 protein expression in human endometrial carcinoma

The expression of connexin 43 was studied using immunohistochemical and Western blot analyses on cell lines of endometrial epithelial origin. Connexin proteins were examined because decreases in their expression and function have been correlated with carcinogenesis. The cell lines were chosen to represent increasing grades of endometrial cancer progression starting from FEEC (fetal endometrial epithelial cells; transformed with SV40 large T antigen) to HEC-1A (stage 1A endometrial carcinoma) to RL-95-2 (grade 2 endometrial carcinoma). Parallel studies using connexin 43 polyclonal antibodies for both Western blots and immunofluorescence showed that the levels of connexin 43 expression were normal endometrial stromal cells = FEEC > HEC-1A > RL-95-2. Consequently, we applied the immunofluorescence assay to analyze paraffin-embedded uterine sections from hysterectomy specimens of patients with normal endometrium and from patients diagnosed with grade 1, 2, and 3 endometrial cancer. Using five different cases from each category, we found an inverse correlation between connexin 43 expression and tumor grade. Our data indicate that connexin 43 expression may be useful as an adjunctive marker of progression for endometrial carcinoma.     

Absolute pitch and pupillary response: effects of timbre and key color

The pitch identification performance of absolute pitch possessors has previously been shown to depend on pitch range, key color, and timbre of presented tones. In the present study, the dependence of pitch identification performance on key color and timbre of musical tones was examined by analyzing hit rates, reaction times, and pupillary responses of absolute pitch possessors (n = 9) and nonpossessors (n = 12) during a pitch identification task. Results revealed a significant dependence of pitch identification hit rate but not reaction time on timbre and key color in both groups. Among absolute pitch possessors, peak dilation of the pupil was significantly dependent on key color whereas the effect of timbre was marginally significant. Peak dilation of the pupil differed significantly between absolute pitch possessors and nonpossessors. The observed effects point to the importance of learning factors in the acquisition of absolute pitch.     

Differential effects of calcium channel antagonists (ω-conotoxin GVIA,nifedipine, verapamil) on the electrically-evoked release of [3H]acetylcholine from the myenteric plexus,phrenic nerve and neocortex of rats

Summary Electrically-evoked release of [³H]acetylcholine from autonomic neurons (myenteric plexus), motoneurons (phrenic nerve) and the central nevous system (neocortex) was investigated in the presence and absence of the calcium channel antagonists -conotoxin GVIA, nifedipine and verapamil, whereby the same species (rat) was used in all experiments. Release of [³H]acetylcholine was measured after incubation of the tissue with [³H]choline.-Conotoxin GVIA markedly reduced (70%) the evoked release of [³H]acetylcholine from the myenteric plexus of the small intestine (IC₅₀: 0.7 nmol/l) with a similar potency at 3 and 10 Hz stimulation. An increase in the extracellular calcium concentration attenuated the inhibitory effect of -conotoxin GVIA. Release of [³H]acetylcholine from the rat neocortex was also inhibited (90%) by -conotoxin GVIA, but the potency was 19-fold lower (IC₅₀: 13 nmol/l). However, the release of [³H]acetylcholine from the phrenic nerve was not reduced by -conotoxin GVIA (100 nmol/l) at 1.8 mmol/l calcium (normal concentration), whereas -conotoxin GVIA inhibited evoked [³H]acetylcholine release by 47% at 0.9 mmol/l calcium. Neither nifedipine (0.1 and 1 mol/l) nor verapamil (0.1, 1 and 10 mol/l) modified the evoked release of [3H]acetylcholine from the myenteric plexus and the phrenic nerve.Acetylcholine release from different neurons appears to be regulated by different types of calcium channels. N-type channels play the dominant role in regulating acetylcholine release from both the myenteric plexus and the neocortex, whereas acetylcholine release from motor nerves is regulated by calcium channel(s) not yet characterized. Send offprint requests to I. Wessler at the above address     

Aortopulmonary collateral artery embolization during postoperative extracorporeal membrane oxygenation after arterial switch procedure

Aortopulmonary collateral arteries sometimes complicate cyanotic congenital heart defects. Combined with a relevant left-right shunt, this could result in massive airway bleeding during and after corrective surgery. A preoperatively diagnosed 1.2 mm small aortopulmonary collateral artery in a newborn suffering from transposition of the great arteries caused life-threatening airway bleeding during surgery. Postoperative extracorporeal membrane oxygenation (ECMO) was necessary, and coil embolization was performed on ECMO to terminate pulmonary bleeding.     

Clonidine induced hyperphagia and weight gain in monkeys

The effect of the -noradrenergic receptor agonist, clonidine, on food intake and weight was examined in ten adult Stumptail macaque monkeys. An intramuscular injection of 0.1 mg/kg of clonidine HCl for seven consecutive days significantly increased food intake from baseline levels throughout treatment. All but two monkeys gained weight during clonidine treatment with seven animals gaining from 5–15% of their original body weight by the end of 1 week.To whom offprint requests should be sent     

Paramagnetic thermosensitive liposomes for MR-thermometry.

MR-thermometry methods have been developed for the guidance and control of thermal therapies such as thermal ablation or regional hyperthermia. However, they are limited to the measurement of temperature changes and, thus, cannot be used to assess absolute temperature values. Paramagnetic thermosensitive liposomes are innovative contrast agents offering the potential to overcome these limitations. They are composed of a gadolinium- or manganese-based compound enclosed by a phospholipid membrane with a distinct gel-to-liquid crystalline phase transition temperature (Tm). At this temperature, the phospholipid membrane changes from a gel-phase to a liquid-crystalline phase which is associated with an increased transmembrane permeability towards solutes and water. Under these conditions, both types of paramagnetic thermosensitive liposomes demonstrate a significant increase in longitudinal (T1) relaxivity, attributed to the release of paramagnetic material from the liposome and/or to the increased water exchange rate between the liposome interior and exterior. Paramagnetic thermosensitive liposomes have already been successfully studied in animal models and have demonstrated a clear correlation between tissue temperature changes and signal intensity changes in MRI. Nevertheless, before entering clinical trials they have to be studied in more detail with regard to dose, pharmacokinetics and toxicity.     

Anwendungen der Ultrahochfeld-MRT in der Neuroonkologie

The introduction of high-field magnetic resonance imaging (MRI) into neuro-oncological imaging allows improved visualization of tumor structures even in the field of T1 and T2-weighted imaging. Susceptibility-weighted imaging (SWI) and time of flight (TOF) angiography in particular greatly benefit from the high field strength. The visualization of tumor vasculature in MRI, which was made possible by high-field technology can potentially be applied to monitoring antiangiogenic therapy. Cerebral metastases can potentially be discovered earlier using high-field technology. Furthermore, high-field technology permits the use of new technologies, such as sodium imaging, which is expected to provide new information in the field of tumor pathophysiology.     

Triggering of suicidal erythrocyte death by radiocontrast agents

Background According to in vitro observations, gadolinium‐containing magnetic resonance (MRT) contrast agents stimulate suicidal cell death or apoptosis. Similar to nucleated cells, erythrocytes may undergo suicidal death or eryptosis, characterized by cell shrinkage and cell membrane scrambling with phosphatidylserine (PS) exposure at the erythrocyte surface. Eryptosis is triggered by increased cytosolic Ca²⁺‐activity. This study explored whether gadolinium‐containing MRT contrast agents stimulate eryptosis. Materials and methods Annexin V‐binding reflecting PS exposure and forward scatter reflecting cell volume were determined in erythrocytes within freshly drawn blood from patients (8♀, 3♂, 29–72 years) prior to and 10 min after administration of gadoterate meglumine (0·1 mmol kg^?1 b.w. Dotarem^®; six patients) or gadobenate dimeglumine (0·05 mmol kg^?1 bw Multi Hance^®; five patients). In a separate series, eryptosis was determined prior to and following in vitro incubation of erythrocytes from 16 blood donors for 4 h with gadoterate meglumine (5 mM Dotarem^®) or gadobenate dimeglumine (5 mM Multi Hance^®). Finally, eryptosis and Fluo3 fluorescence reflecting cytosolic Ca²⁺ were determined in vitro following exposure to Gd³⁺. Data were analysed using paired t‐test or anova with Tukey’s test as post‐test. Results The MRT contrast agents such as gadoterate meglumine (Dotarem^®) and gadobenate dimeglumine (Multi Hance^®) significantly increased the percentage of eryptotic cells. Moreover, in vitro exposure to gadoterate meglumine (5 mM), gadobenate dimeglumine (5 mM) or Gd³⁺ (1·9 μM) stimulated eryptosis in vitro. The effect of Gd³⁺ was paralleled by increase in cytosolic Ca²⁺‐activity. Conclusions MRT contrast agents may stimulate suicidal erythrocyte death or eryptosis in vitro and in vivo.     

Procoagulant soluble tissue factor is released from endothelial cells in response to inflammatory cytokines

Inflammatory cytokines alter the hemostatic balance of endothelial cells (ECs). Alternatively spliced human tissue factor (asHTF), a soluble isoform of tissue factor (TF), has recently been detected in ECs, possibly contributing to procoagulability. Agonists regulating asHTF expression and release are yet unknown. This study examines the effect of TNF-alpha and IL-6 on the endothelial expression of both TF variants and delineates the impact of asHTF on the procoagulability of extracellular fluids. asHTF and TF mRNA were assessed by real-time PCR, and asHTF, TF, and tissue factor pathway inhibitor (TFPI) proteins by Western blot and fluorescence microscopy before and after stimulation with TNF-alpha (10 ng/mL) or IL-6 (10 ng/L). The procoagulability of cell supernatant was analyzed by a chromogenic assay with or without phospholipid vesicles. We found asHTF mRNA to be maximally increased 10 minutes after TNF-alpha and 40 minutes after IL-6 treatment (asHTF/GAPDH ratio 0.0223+/-0.0069 versus 0.0012+/-0.0006 for control, P<0.001 and 0.0022+/-0.0004 versus 0.0012+/-0.0007, P<0.05, respectively). Not only was asHTF increased, but also TFPI decreased after cytokine treatment. asHTF was found in the supernatant as early as 5 hours after TNF-alpha stimulation, supporting factor Xa generation after relipidation (6.55+/-1.13 U versus 2.99+/-0.59 U in control supernatant, P<0.00001). Removal of asHTF from supernatants by immunoprecipitation diminished its procoagulability to baseline. The soluble TF isoform expressed and released from ECs in response to inflammatory cytokines becomes procoagulant in the presence of phospholipids. Thus, asHTF released from ECs is a marker for and a contributor to imbalanced hemostasis.