Mitosenverteilung in der larvalen Rumpfepidermis vonSalamandra maculosa Laur.

Summary In the larval epidermal trunk region ofSalamandra maculosa, the total number of mitoses of both sides is approximately the same. This applies to the differentiated Leydig cells as well as to the rest of the epidermis cells.With respect to the meristic segmentation of the trunk, we find within the single segments a regular rise of the mitotic rate, which alternates from one side to the other.From the total number of mitoses found in the epidermis of the trunk, approximately 40% can be accounted for to the dorsal and 60% to the ventral region of the trunk. The number of cells is the same for both the ventral and dorsal region.     

Über die Einwirkung des Schilddrüsenhormons auf die Ossifikation

Summary Larvae ofSalamandra salamandra quadrivirgata Dürigen and tadpoles ofXenopus laevis Daud, treated with a percutaneous application of thyroxin, show a more intensive calcification of their skeletal system after a precocious metamorphosis. The calcified area of bones is increased; additional centres of calcification can be distinguished in quite a number of other skeletal elements. By thyroxin-soaked agar implants in the hindlimbs ofAmbystoma mexicanum, deposition of calcium salts is furthered in the bones of the leg treated, as well as in the adjacent pelvic girdle, thus demonstrating that the thyroid hormone exerts a direct effect upon calcification. It is supposed that during normal metamorphosis the thyroid gland plays an equal part in the process of calcification in the skeletal system.     

Künstliche Niere mit Kapillarsystem für den Stoffaustausch

Summary A particularly efficient removal of urea and similar substances by dialysis in an artificial kidney is obtained if both blood and dialyzing liquid are allowed to flow in countercurrent through channels a few hundredths of a mm thick and separated from each other by a membrane about 1/100 of a mm thick. In order practically to realize the flow required, about two thousand of these narrow channels, each of a length of about 2 cm, are arranged parallel to form a capillary net system.Four elements, each consisting of 2000 narrow channels, are needed in order to obtain a clearance of 80 ml/min. The quantity of blood needed to fill the elements is about 5 cm³ for each element.

---

---

Vorgetragen am Kongress der «3^o riunioni medico chirurgiche internazionali», Turin 1957.     

The chemistry and pharmacology of hydrotrichlorothiazide

Zusammenfassung In der Reihe der Dihydro-benzothiadiazine wurde mit Hydrotrichlorthiazid (III) ein neues, ausserordentlich stark wirksames Diuretikum gefunden. Herstellung und pharmakologische Evaluation werden kurz beschrieben. Im Vergleich zu Hydrochlorthiazid (I) ist III beim Hundper os bis zu 20mal stärker diuretisch wirksam.     

Three-dimensional structure of the bacterial protein-translocation complex SecYEG

Transport and membrane integration of polypeptides is carried out by specific protein complexes in the membranes of all living cells. The Sec transport path provides an essential and ubiquitous route for protein translocation. In the bacterial cytoplasmic membrane, the channel is formed by oligomers of a heterotrimeric membrane protein complex consisting of subunits SecY, SecE and SecG. In the endoplasmic reticulum membrane, the channel is formed from the related Sec61 complex. Here we report the structure of the Escherichia coli SecYEG assembly at an in-plane resolution of 8 A. The three-dimensional map, calculated from two-dimensional SecYEG crystals, reveals a sandwich of two membranes interacting through the extensive cytoplasmic domains. Each membrane is composed of dimers of SecYEG. The monomeric complex contains 15 transmembrane helices. In the centre of the dimer we observe a 16 x 25 A cavity closed on the periplasmic side by two highly tilted transmembrane helices. This may represent the closed state of the protein-conducting channel.     

Estimating the Cluster Tree of a Density by Analyzing the Minimal Spanning Tree of a Sample

runt pruning , a new clustering method that attempts to find modes of a density by analyzing the minimal spanning tree of a sample. The method exploits the connection between the minimal spanning tree and nearest neighbor density (e.g. normal mixture) or about the geometric shapes of the clusters, and is computationally feasible for large data sets.     

Über die Struktur pflanzlicher Karotinkriställchen

Summary Crystals of carotene in plant cells (carrot root, corona ofNarcissus etc.) have been attributed to the orthorhombic or the hexagonal system. However, an optical investigation showed that they have a lower symmetry. In the case of the crystals in the corona ofNarcissus, the structural identity with synthetic-carotene is proved by X-ray and electron diffraction analysis. Although the geometry of the electron diffraction patterns is almost indistinguishable from hexagonal, its reflections can be identified with those from the planes of the monoclinic lattice of-carotene. The face of the plate-shaped crystals corresponds to (102).     

The European dimension for the mouse genome mutagenesis program

The European Mouse Mutagenesis Consortium is the European initiative contributing to the international effort on functional annotation of the mouse genome. Its objectives are to establish and integrate mutagenesis platforms, gene expression resources, phenotyping units, storage and distribution centers and bioinformatics resources. The combined efforts will accelerate our understanding of gene function and of human health and disease.