Determination of "extractables" on polymer materials by means of HPLC-MS.

In biopharmaceutical processes, in the area of food and medical technology a variety of devices is used. These devices consist of various polymers. The detection and identification of potential extractables from these polymers during application are requested by the regulatory bodies. For risk and toxicity assessment, both identification and quantification of extractables are necessary. This article describes the development of a LS-MS methodology transfered from an established HPLC-UV-VIS method for full extractables analysis of sterile-grade filtration cartridges.

[Effect of primary fracture management on craniocerebral trauma in polytrauma. An animal experiment study]. / Der Einfluss der primären Frakturversorgung auf ein Schädel-Hirn-Trauma beim Polytrauma. Eine tierexperimentelle Studie.

Severe head trauma (BI) associated with long bone fractures is present in about 60% of polytraumatized patients admitted to hospital. However, there is no consensus regarding early fracture stabilization in such patients. In an experimental sheep study, the influence of intramedullary nailing of the femur (IMNF) on a cold-induced, vasogenic brain edema (method of Klatzo) in combination with traumatic hemorrhagic shock (THS) was investigated. Three animal groups (n = 6) were explored: group A, only BI; group B, BI and THS; group C, BI, THS and IMNF. The animals remained intubated, on controlled ventilation, sedated and received analgesia during the whole experiment. For a period of 6 h after the cold-induced brain injury the hemodynamic changes were measured and the intracranial pressure (ICP) was recorded in the left and the right hemisphere continuously. The hemorrhagic shock (MAP = 60 mm Hg) was maintained over 1.5 h. At the end of the reperfusion period (2 h) the nailing of the femur was performed. The animals were killed and the percentage water content of the brain was determined and compared with the brain water content of a control group (n = 6). There were no significant differences in ICP between groups A, B and C before or after IMNF, but in group C the ICP increased significantly after nailing. Brain water content in group C was significantly higher than in the control group and slightly significantly higher than in groups A and B. Brain edema and ICP are increased by IMNF.(ABSTRACT TRUNCATED AT 250 WORDS)

THE SKELETON SPACE: A FINITE SET OF ORGANIC DESIGNS.

The structures of animal skeletons converge repeatedly on a limited number of architectural designs that can be constructed by growing organisms and that are functionally viable, although often not optimal. Properties of materials, construction rules that determine patterns of development, and physical constraints exerted by the requirements of function suggest that organic structure must necessarily approach these recurrent elements of design. A set of potential designs for the elements of animal skeletons is derived in terms of geometric and construction rules and the properties of materials. Skeletons of actual living and extinct organisms are matched with the possibilities defined within this theoretical morphospace. This provides a metric of skeletal complexity and of the extent to which various groups of animals have been able to exploit the range of possibilities of organic structure. These analyses show that the most evolutionarily advanced animals within a given phylum do not have the most complex skeletons; that arthropods are less morphologically diverse than vertebrates and molluscs; that the physical constraints of life on land and in the air substantially limit the variety of skeletal structures suitable for life in these environments; and that overall the range of possible skeletal designs has been very fully exploited by living and extinct organisms. These results strongly support the hypothesis that the essential elements of organic design are inherent in the material properties of the universe. The organizational properties of animal skeletons suggest that their design elements are fixed point attractors, structures that we characterize as topological attractors that evolution cannot avoid.

Constructional morphology: the analysis of constraints in evolution dedicated to A. Seilacher in honour of his 60. birthday.

Evolutionary change is opportunistic, but its course is strongly constrained in several fundamental ways. These constraints (historical/phylogenetic, functional/adaptive, constructional/morphogenetic) and their dynamic relationships are discussed here and shown to constitute the conceptual framework of Constructional Morphology. Notwithstanding recent published opinions which claim that the "discovery" of constraints renders Neodarwinian selection theory obsolete, we regard the insights of Constructional Morphology as being entirely consistent with this theory. As is shown here in the case of the Hyracoidea, formal analysis of the constraints which have framed the evolution of various characters extends our understanding of the evolution of a taxon.

Development of dentition and dermal skeleton in embryonic Scyliorhinus canicula.

Serial sections ranging from very young embryos to hatched juveniles and whole embryos of Scyliorhinus show that dentition and dermal skeleton belong to two independent secondary developmental fields that differ both developmentally and structurally. The development of the dentition starts very early, with a thickening of the ectoderm in the region of the mouth (stage 04), the invagination of the dental lamina (stage 18), and the formation of the germs of the first generation (stage 20). Tooth replacement movements start only near the end of embryogenesis (stage 35). Scale germs, on the other hand, first begin to form at stage 24. Scales erupt shortly before the animal hatches (stage 43). Only one scale generation is formed during embryogenesis. The forces which erupt the scales may come from fluid pressures in vacuoles of the fibrous layer of the dermis. Those which erupt the teeth probably also result from similar fluid pressures. The crown and upper part of the base of scales and teeth are formed by cells of the inner dental epithelium which are differentiated from the ectoderm. They are also formed by odontoblasts which are derived from the vascular layer of the dermis. However, the basal plates of scales and teeth containing the anchoring fibers are formed by osteoblasts, which are derived from the fibrous layer of the dermis.

[Scanning electron microscopy of the dental enamel from a dermoid teratoma]. / Rasterelektronenmikroskopie des Zahnschmelzes aus einem Dermoidteratom

Tooth enamel in the dermal teratoma is constructed very much like normal human tooth enamel, but is relatively less mineralized because of low phosphate supply. Prism bands are not present; the reasons for this are not clear. In the inner half of the enamel are numerous lumpy aggregates budded off from the tissue of the enamel organ. Enamel in the vicinity of these aggregates is abnormally constructed.

[Regulating and limiting factors in evolution]. / Lenkende und limitierende faktoren in der evolution

It is shown in a literature review, that in the Typostrophic Theory autonomous mechnisms in the organism are considered as the factors which play a decisive role in orienting and controlling the evolutionary process. Selection is a controlling factor of only minor importance. The synthetic Theory, on the other side, says that phylogenetic changes are not random or controlled by "internal factors" but can always be considered as adaptive remodellings. They are achieved by selection acting on the variation within populations. Ecological, historical and "bautechnische" (fabricational) factors are considered as limiting mechanisms in the evolutionary process. They are discussed in detail in the text.