[Nuclear Her2 expression in hepatocytes in liver disease]. / Nukleäre HER2/neu-Expression in Hepatozyten bei Lebererkrankungen.

BACKGROUND: Her2 is a well-known member of the epidermal growth factor receptor (EGFR) superfamily, a group of transmembrane receptors that mediate effects of proliferation and survival and thus play an important role in tumorigenesis. EGFRs can translocate to the nucleus and may mediate DNA repair and cell cycle arrest. OBJECTIVES: The aim of this study was to characterize hepatocellular Her2 expression in different liver diseases. MATERIALS AND METHODS: Her2 expression was analyzed by immunohistochemistry in 674 liver biopsies. RESULTS: Hepatocytes often revealed a nuclear and cytoplasmic Her2 expression in different liver diseases with the strongest association to alcoholic steatohepatitis. The histologic parameters of hepatocellular ballooning and the presence of Mallory-Denk bodies strongly correlated with Her2 positivity. Interestingly, in hepatocellular carcinomas (HCC) nuclear Her2 expression was frequently observed. Furthermore, Her2 positive hepatocytes showed a loss of estrogen receptor expression and increased expression of p21, a cell cycle regulator, and pSTAT3, a downstream effector of nuclear Her2. CONCLUSIONS: Nuclear Her2 expression in hepatocytes with further metabolic and cell cycle alterations may imply a so far unknown mechanism of a stress response. So far, the effects on disease course and a possible role of nuclear Her2 in progression to HCC are unclear and the subject of future research.

Febrile ulceronecrotic Mucha-Habermann disease following suspected hemorrhagic chickenpox infection in a 20-month-old boy.

We present the youngest pediatric patient so far with febrile ulcerative Mucha-Haberman disease (FUMHD) after an admitting clinical picture of hemorrhagic varicella infection. With a time to diagnosis of 25 days, the 20-month-old boy responded to low dose cyclosporine and prednisolone given for 3 months and is free of disease after 4 years of follow up. We describe a polyclonal CD8+ T cell response with elevated pro-inflammatory cytokines and a fivefold upregulation of the high-affinity Fc receptor type I (CD64) on granulocytes. Early consideration of FUMHD in the differential diagnosis of a systemic inflammatory disease combined with a generalized necrotizing rash is important for early and adequate management of children with this rare and challenging disease.

Arabidopsis and the heat stress transcription factor world: how many heat stress transcription factors do we need?

Sequencing of the Arabidopsis genome revealed a unique complexity of the plant heat stress transcription factor (Hsf) family. By structural characteristics and phylogenetic comparison, the 21 representatives are assigned to 3 classes and 14 groups. Particularly striking is the finding of a new class of Hsfs (AtHsfC1) closely related to Hsf1 from rice and to Hsfs identified from frequently found expressed sequence tags of tomato, potato, barley, and soybean. Evidently, this new type of Hsf is well expressed in different plant tissues. Besides the DNA binding and oligomerization domains (HR-A/B region), we identified other functional modules of Arabidopsis Hsfs by sequence comparison with the well-characterized tomato Hsfs. These are putative motifs for nuclear import and export and transcriptional activation (AHA motifs). There is intriguing flexibility of size and sequence in certain parts of the otherwise strongly conserved N-terminal half of these Hsfs. We have speculated about possible exon-intron borders in this region in the ancient precursor gene of plant Hsfs, similar to the exon-intron structure of the present mammalian Hsf-encoding genes.

The balance of nuclear import and export determines the intracellular distribution and function of tomato heat stress transcription factor HsfA2.

Tomato heat stress transcription factor HsfA2 is a shuttling protein with dominant cytoplasmic localization as a result of a nuclear import combined with an efficient export. Besides the nuclear localization signal (NLS) adjacent to the oligomerization domain, a C-terminal leucine-rich motif functions as a nuclear export signal (NES). Mutant forms of HsfA2 with a defective or an absent NES are nuclear proteins. The same is true for the wild-type HsfA2 if coexpressed with HsfA1 or in the presence of export inhibitor leptomycin B (LMB). Fusion of the NES domain of HsfA2 to HsfB1, which is a nuclear protein, caused export of the HsfB1-A2NES hybrid protein, and this effect was reversed by the addition of LMB. Due to the lack of background problems, Chinese hamster ovary (CHO) cells represent an excellent system for expression and functional analysis of tomato Hsfs. The results faithfully reflect the situation found in plant cells (tobacco protoplasts). The intriguing role of NLS and NES accessibility for the intracellular distribution of HsfA2 is underlined by the results of heat stress treatments of CHO cells (41 degrees C). Despite the fact that nuclear import and export are not markedly affected, HsfA2 remains completely cytoplasmic at 41 degrees C even in the presence of LMB. The temperature-dependent conformational transition of HsfA2 with shielding of the NLS evidently needs intramolecular interaction between the internal HR-A/B and the C-terminal HR-C regions. It is not observed with the HR oligomerization domain (HR-A/B region) deletion form of HsfA2 or in HsfA2-HsfA1 hetero-oligomers.

High-resolution localization of Drosophila Spt5 and Spt6 at heat shock genes in vivo: roles in promoter proximal pausing and transcription elongation.

Recent studies have demonstrated roles for Spt4, Spt5, and Spt6 in the regulation of transcriptional elongation in both yeast and humans. Here, we show that Drosophila Spt5 and Spt6 colocalize at a large number of transcriptionally active chromosomal sites on polytene chromosomes and are rapidly recruited to endogenous and transgenic heat shock loci upon heat shock. Costaining with antibodies to Spt6 and to either the largest subunit of RNA polymerase II or cyclin T, a subunit of the elongation factor P-TEFb, reveals that all three factors have a similar distribution at sites of active transcription. Crosslinking and immunoprecipitation experiments show that Spt5 is present at uninduced heat shock gene promoters, and that upon heat shock, Spt5 and Spt6 associate with the 5' and 3' ends of heat shock genes. Spt6 is recruited within 2 minutes of a heat shock, similar to heat shock factor (HSF); moreover, this recruitment is dependent on HSF. These findings provide support for the roles of Spt5 in promoter-associated pausing and of Spt5 and Spt6 in transcriptional elongation in vivo.

The role of AHA motifs in the activator function of tomato heat stress transcription factors HsfA1 and HsfA2.

Using reporter assays in tobacco protoplasts and yeast, we investigated the function of the acidic C-terminal activation domains of tomato heat stress transcription factors HsfA1 and HsfA2. Both transcription factors contain short, essential peptide motifs with a characteristic pattern of aromatic and large hydrophobic amino acid residues embedded in an acidic context (AHA motifs). The prototype is the AHA1 motif of HsfA2, which has the sequence DDIWEELL. Our mutational analysis supports the important role of the aromatic and large hydrophobic amino acid residues in the core positions of the AHA motifs. The pattern suggests the formation of an amphipathic, negatively charged helix as the putative contact region with components of the basal transcription complex. In support of this concept, proline or positively charged residues in or adjacent to the AHA motifs markedly reduce or abolish their activity. Both AHA motifs of HsfA1 and HsfA2 contribute to activator potential, and they can substitute for each other; however, there is evidence for sequence and positional specificity.

[Experimental animal studies on esophagus-stomach replacement with plicated small and large intestine]. / Tierexperimentelle Studie zum Osophagus-Magen-Ersatz durch Dünn- und Dickdarm mit Plicatio.

Animal experimental investigationns shows a reliable anastomosis by means of a plication of the esophagus anastomosis with the small intestine or the right colon after resectio of the stomach and the esophagus. The author developed a special method for the mobilisation of the small intestine and the right colon for the transposition in the thoracic cavity. Angiographic examinations showed optimal circulatory conditions of the interpolation during the whole experiment. Microscopical examinations confirm the uncomplicated healing of the anastomosis.

[The determination of verapamil in maternal and fetal blood (author's transl)]. / Nachweis von Verapamil im mütterlichen und fetalen Blut des Menschen.

During the late first stage of labor and during the second stage of labor seven women in labor received an intravenous infusion during 60-110 minutes of verapamil at 2 g/k/per minute. Immediately following delivery of the infant, maternal and cord blood was drawn and the verapamil level measured by gas chromatography. The serum levels in the maternal blood were from 5.4 to 33.6 ng/ml. (Mean value 19.3 +/- 3.3 ng/ml) and the cord blood concentrations were 4.3-17.8 ng/ml (Mean value 8.5 +/- 1.9 ng/ml). The mean fetal serum level of verapamil was 51.4% of the mean maternal value.