Malignant blue nevus with metastasis to lymph nodes and brain

We report a patient who developed malignant transformation of a cellular blue nevus. At the age of 19 years the congenital, pigmented tumor on the left buttock was histopathologically diagnosed as cellular blue nevus. Thirty years later the tumor dramatically increased in size, involving the entire left buttock within several months. Multiple biopsies revealed the presence of a cellular blue nevus within the papillary dermis and an invasive, pleomorphic pigmented sarcoma in the depth of the tissue spreading into subcutis and skeletal muscle. Both benign and malignant cells were S100+, vimentin+ and HMB-45+, but only the malignant tumor cells stained positive for the proliferating cell nuclear antigen. General examination disclosed multiple metastases in the paraaortal lymph nodes and the retroperitoneum as well as a single brain metastasis. Despite palliative therapy with ionizing radiation and chemotherapy, the patient developed generalized metastases and died within weeks. This case clearly confirms that cellular blue nevi have the potential for malignant transformation and that the malignant variant may behave aggressively just as a malignant melanoma.     

Solid-state properties of hot-pressed TiB2 ceramics

Due to the increasing industrial interest in TiB₂ the present work was accomplished to establish various solid-state properties of TiB₂ and to study the influence of sintering aids and different powder conditioning methods on the densification behaviour of TiB₂.

The powders were hot-pressed in graphite dies with various loads up to 45 MPa and the vertex temperature of 1800 °C was held for 1 h. For the pure, non-activated powders theoretical densities between 97.4% and 99.5% were obtained at a pressure of 45 MPa. Hot-pressed activated powders at this pressure led to densities of up to 99.9%. The addition of 0.5 wt.% of various sintering aids also increased the densities. It is shown that pre-alloying TiB₂ with CrB₂ is to favour over mixing the powders. If TiB₂ and the sintering aid were mixed the best result was obtained with Cr₂N. Ceramics with high Young’s moduli and hardnesses were obtained. The Poisson’s ratios of two samples were 0.08 and 0.09, respectively, which are the lowest known values for a ceramic hard material. The heat conductivity of pure TiB₂ is approximately 1/4 of that of copper and the electrical resistivity is only 6 times higher than that of copper.     

Die Einführung von Informationsmanagement-Standards in Fertigungsunternehmen

Ohne Zusammenfassung     

Acute non-insulin-like stimulation of rat muscle glucose metabolism by troglitazone in vitro

1. The direct short-term effects of troglitazone on parameters of glucose metabolism were investigated in rat soleus muscle strips. 2. In muscle strips from Sprague-Dawley rats, troglitazone (3.25 micromol l(-1)) increased basal and insulin-stimulated glucose transport by 24% and 41%, respectively (P<0.01 each). 3. In the presence of 5 nmol l(-1) insulin, stimulation of glucose transport by 3.25 micromol l(-1) troglitazone was accompanied by a 36% decrease in glycogen synthesis, while glycolysis was increased (112% increase in lactate production) suggesting a catabolic response of intracellular glucose handling. 4. Whereas insulin retained its stimulant effect on [3H]-2-deoxy-glucose transport in hypoxia-stimulated muscle (by 44%; c.p.m. mg(-1) h(-1): 852+/-77 vs 1229+/-75, P<0.01), 3.25 micromol l(-1) troglitazone failed to increase glucose transport under hypoxic conditions (789+/-40 vs 815+/-28, NS) suggesting that hypoxia and troglitazone address a similar, non-insulin-like mechanism. 5. No differences between troglitazone and hypoxia were identified in respective interactions with insulin. 6. Troglitazone acutely stimulated muscle glucose metabolism in a hypoxia/contraction-like manner, but it remains to be elucidated whether this contributes to the long-term antidiabetic and insulin enhancing potential in vivo or is to be regarded as an independent pharmacological effect.