SS18-SSX fusion protein-induced Wnt/ß-catenin signaling is a therapeutic target in synovial sarcoma.

Synovial sarcoma is a high-grade soft tissue malignancy characterized by a specific reciprocal translocation t(X;18), which leads to the fusion of the SS18 (SYT) gene to one of three SSX genes (SSX1, SSX2 or SSX4). The resulting chimeric SS18-SSX protein is suggested to act as an oncogenic transcriptional regulator. Despite multimodal therapeutic approaches, metastatic disease is often lethal and the development of novel targeted therapeutic strategies is required. Several expression-profiling studies identified distinct gene expression signatures, implying a consistent role of Wnt/ß-catenin signaling in synovial sarcoma tumorigenesis. Here we investigate the functional and therapeutic relevance of Wnt/ß-catenin pathway activation in vitro and in vivo. Immunohistochemical analyses of nuclear ß-catenin and Wnt downstream targets revealed activation of canonical Wnt signaling in a significant subset of 30 primary synovial sarcoma specimens. Functional aspects of Wnt signaling including dependence of Tcf/ß-catenin complex activity on the SS18-SSX fusion proteins were analyzed. Efficient SS18-SSX-dependent activation of the Tcf/ß-catenin transcriptional complex was confirmed by TOPflash reporter luciferase assays and immunoblotting. In five human synovial sarcoma cell lines, inhibition of the Tcf/ß-catenin protein-protein interaction significantly blocked the canonical Wnt/ß-catenin signaling cascade, accompanied by the effective downregulation of Wnt targets (AXIN2, CDC25A, c-MYC, DKK1, CyclinD1 and Survivin) and the specific suppression of cell viability associated with the induction of apoptosis. In SYO-1 synovial sarcoma xenografts, administration of small molecule Tcf/ß-catenin complex inhibitors significantly reduced tumor growth, associated with diminished AXIN2 protein levels. In summary, SS18-SSX-induced Wnt/ß-catenin signaling appears to be of crucial biological importance in synovial sarcoma tumorigenesis and progression, representing a potential molecular target for the development of novel therapeutic strategies.

[Neurological complications and loss of efficacy with intrathecal pain therapy]. / Neurologische Komplikationen und Wirkverlust unter intrathekaler Schmerztherapie. Drei Fallberichte und Auswertung der Literatur.

In a new guideline issued by the German Association for the Study of Pain, intrathecal opioid therapy is described as proven to be effective with relatively few side effects. We reviewed this statement by analysis of the available literature and critical evaluation of the clinical course in a few of our own patients (n=3). In these cases (as well as in a further eight patients), explantation and a switch to oral opioids led to distinctly better alleviation of pain and abatement of the unwanted effects. The problems we discuss do not appear to be rare instances, but by all means complications that are frequently described. The long-term efficacy of intrathecal opioids has not been adequately verified; moreover, their potency is not high. The frequency of undesired events is comparable to that of oral opioid medication, but serious neurological complications are possible. To avoid dose escalations and to recognize neurological complications in time, diligent monitoring by the surgeon or an experienced pain center is essential.

Update on therapies for acute ischemic stroke.

Acute ischemic stroke is now considered a neurological emergency for which there are new therapies. Neurosurgeons and neurologists need to remain apprised of advances in this field. The authors discuss approved and emerging therapies for patients suffering from acute ischemic stroke, based on a review of recent publications. Currently, intravenous tissue-type plasminogen activator is the only Food and Drug Administration-approved therapy for acute ischemic stroke. Intraarterial delivery of thrombolytics is a promising treatment and may be effective in selected patients. Other therapies for acute cerebral ischemia are intriguing but still in the investigational stages.

[Are tramadol enantiomers for postoperative pain therapy better suited than the racemate? A randomized, placebo- and morphine-controlled double blind study]. / Sind Tramadol-Enantiomere für die postoperative Schmerztherapie besser geeignet als das Racemat? Eine randomisierte, Plazebo- und Morphin-kontrollierte Doppelblindstudie.

The goal of this prospective, randomised and double-blind pilot-study was to investigate the analgesic potency and the side-effects of tramadol enantiomers in clinical practice. One hundred patients recovering from orthopaedic surgery with a postoperative pain intensity of more than 50 on a visual analogue scale 0-100 mm (Table 1) were recruited for the study. They were treated in a randomised, double-blind way with a maximal dose of 150 mg i.v.(+)-,(-)-tramadol, racemate, or 15 mg i.v. morphine or saline in the placebo group (5 groups, 20 patients each). The primary criterium of efficacy was the number of responders defined as patients with a pain reduction of at least 20 on VAS after 40 min. In case of pain, responders were allowed to continue with the double-blind drug up to six hours. The non-responders were treated with morphine as the rescue analgesic. The secondary criterium was the incidence and severity of side-effects. Six patients terminated the study prematurely. One patient was excluded because of an allergic reaction to morphine, one patient could not be treated sufficiently with morphine, four were excluded because of protocol violations. There were 8 responders in the (+)-tramadol-,6 in the (-)-tramadol- and 6 in the racemate group, 16* (P < 0.05) in the morphine group, and 5 in the placebo group. Pain intensity after 40 min was reduced by 20 (p < 0.05), 17 (p < 0.05), 17 (p < 0.05), 36 (p < 0.01 vs placebo, p < 0.05 vs (+)-,(-)-tramadol, and racemate group) and 5 mm on the VAS in the (+)-, (-)-, (+/-)-tramadol-, morphine- and placebo-group, respectively. Thirty eight adverse events like nausea, vomiting, PCO2-increase, and urinary retention occurred in 20 patients, most frequently in the (+)-tramadol- and morphine group. Sedation was significantly less profound in the (-)-tramadol group 1-4 h postoperatively. There were no side-effect in the tramadol racemate group. The enantiomers were equal to the racemate in analgesic potency, but inferior by far to morphine. They showed more adverse events and, hence, can not be preferred to the racemate in postoperative pain therapy.

Hyperinsulinemia after pancreatic transplantation. Prediction by a novel computer model and in vivo verification.

OBJECTIVE: The authors evaluated systemic venous insulin release as a cause of the hyperinsulinemia (HNS) associated with pancreatic transplantation (PTX) with respect to the mechanism and metabolic consequences. SUMMARY BACKGROUND DATA: Many investigators believe the postoperative anatomy associated with common PTX techniques to be the sole cause of the two- to threefold posttransplantation HINS. However, this concept remains to be conclusively proved and characterized quantitatively. METHODS: The authors used three approaches to achieve their objectives. First, a computer model was generated based on established data concerning blood flow and tissue insulin extraction to determine whether it was mathematically possible for HINS to be caused by systemic insulin release. Second, HINS clamps were applied to normal dogs using the Andres clamp technique to quantify the in vivo differences in peripheral insulin levels and the metabolic consequences of systemic versus portal insulin infusion. Third, prolonged insulin half-life was evaluated as a possible mechanism of HINS from systemic insulin release by determination of biexponential rates of plasma disappearance from an endogenous pulse of insulin in surgically induced dog models of systemic and portal insulin release. RESULTS: First, the computer model calculated a 1.4- to 2.9-fold increase in peripheral venous insulin levels with systemic versus portal insulin release, verifying mathematically the concept of HINS resulting from systemic insulin release. Second, the actual systemic insulin infusion produced a 1.3- to 1.4-fold increase in peripheral venous insulin levels compared with portal infusion (p < 0.05). No significant differences in hepatic glucose output, total glucose disposal, or glucose infusion requirements were seen. Third, although the basal insulin level was twofold higher in the surgically induced animal models with systemic insulin release (p < 0.003), there were no differences in biexponential insulin clearance parameters. CONCLUSIONS: The HINS produced by systemic insulin release did not significantly alter glucose metabolism and was not the result of altered peripheral insulin clearance parameters. In vivo systemic venous insulin infusion studies produce HINS, but not to the degree calculated by mathematic modeling or that occurs after clinical PTX, making it likely that other factors also play a role in the HINS after PTX.

Nontoxic and durable salt bridges using hydroxyethylmethacrylate hydrogels.

Polyhydroxyethylmethacrylate polymers (poly-HEMA) form hydrogels that provide an excellent alternative to agar in the production of salt bridges for use in bioelectrochemical experiments. A method for the simple production of poly-HEMA salt bridges is described. The poly-HEMA bridges were compared with agar bridges of similar geometry. Whereas poly-HEMA salt bridges have a conductivity that is 20 times lower than that of agar bridges of a similar geometry, poly-HEMA bridges are capable of dissipating twice the power compared with agar bridges. The mechanical properties of the poly-HEMA bridges make them easy to manufacture, store, and sterilize. When agar bridges were compared with poly-HEMA bridges in long-term cell culture experiments, the failure rate of the agar bridges was found to be approximately 10% per week vs. a virtually nonexistent failure rate for the poly-HEMA bridges. Because poly-HEMA salt bridges are reliable, durable, and nontoxic to cells, they are a practical alternative to agar salt bridges in certain experimental designs.

Glutathione peroxidase activity in various types of blood cells in multiple sclerosis.

Previous studies demonstrated a significantly lower mean activity of glutathione peroxidase (GSH-Px) in erythrocytes of patients with multiple sclerosis than in control groups of normal subjects or patients with various neurological disorders. The present investigation has demonstrated that, in contradistinction to erythrocytes, a normal activity of GSH-Px is found in lymphocytes, granulocytes and platelets of multiple sclerosis patients. These results were obtained both with hydrogen peroxide, which serves as a specific substrate for selenium dependent GSH-Px, and t-butyl hydroperoxide which reacts both with selenium dependent and independent GSH-Px.

Plasma c-AMP during the normal menstrual cycle and under different hormonal treatment.

There is a highly significant difference between the plasma c-AMP value of the first and the second half of the normal menstrual cycle (days 1-12: 10.5 +/- 2.0 pmol, x +/- SEM; days 13-16: 21.9 +/- 4.5; days 17-28: 19.9 +/- 2.0; p less than 0.001). In amenorrheic patients plasma c-AMP levels were nearly the same as in normal women during the first half of the menstrual cycle (11.1 +/- 2.5). Plasma c-AMP of amenorrheic women was significantly higher under HMG treatment (16.7 +/- 2.5; p less than 0.01). Under oral contraception with estrogens (alone) or with low doses of gestagens the plasma c-AMP values were comparable to those of the amenorrheic women, but there was a dose-dependent increase of plasma c-AMP under gestagen application. It is concluded that the midcyclic plasma c-AMP increase is mainly caused by the gonadotropin effect, and is followed by the progesterone effect during the second half of the menstrual cycle. Therefore, plasma c-AMP levels are in accordance to the stages of the menstrual cycle reflecting their different endocrine pattern.

Plasma cAMP in normal and abnormal human pregnancy.

Plasma cAMP was determined using the method of Tovey et al. in normal pregnant women with a mean concentration of 18.9 +/- 0.8 pmol/ml (x- +/- SEM). Between weeks 9-12 and 33-36 of gestation, there were two peaks, with a mean cAMP of 22.5 +/- 2.4 which were significantly increased in comparison to the other weeks of pregnancy. Significantly decreased values were found in patients with threatened abortion (weeks 12-28) which terminated in abortion (11.6 +/- 2.4; p < 0.01). In premature labor no differences were found. During therapy with fenoterol there were highly significantly increased plasma cAMP levels (48.2 +/- 2.8; p < 0.0005). During thyroid hormone therapy in euthyroid goiter, cAMP was significantly decreased (14.0 +/- 1.4; p < 0.05). 1 week after cessation of therapy a highly significant increase of cAMP was observed (38.2 +/- 6.9; p < 0.0005). There was a negative linear regression between T3 and cAMP (2p < 0.01). In pregnancy with hypertension cAMP was significantly elevated (30.5 +/- 3.8 p < 0.0005), but nearly normal under antihypertensive therapy. In pregnancy with edema only, no difference was found. Induction of labor with PGE2 alpha was followed by a decrease of plasma cAMP.