35. Ätio-Pathogenese der Pankreatitis

Zusammenfassung Zu den bisher bekannten Ursachen einer Pankreatitis kam in den letzten Jahren eine Reihe weiterer Faktoren, die allein oder zusammen mit anderen eine akute oder chronische Schädigung der Bauchspeicheldrüse bewirken können. Die im Rahmen einer Erkrankung der extrahepatischen Gallenwege ablaufende biliäre Pankreatitis ist in der Regel harmlos. Zu ausgedehnten Organschäden können metabolisch-nutritive Defekte, induzierte Allergien, Infektionen, Zirkulationsstörungen, Verletzungen, Vergiftungen und medikamentöse Einflüsse führen. In zunehmendem Ausmaß ist auch in Mitteleuropa ein Ansteigen alkoholischer Pankreatitiden festzustellen.

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Etiopathogenesis of pancreatitis

Summary In addition to well-known causes of pancreatic disease, further etiological factors must be considered. They may lead to acute or chronic lesions of the pancreas alone or in combination with other causes. As a rule, biliary pancreatitis complicating diseases of the extrahepatic bile ducts heals without damage. Metabolic or nutritional defects, induced allergies, infections, impaired circulation, trauma, poisoning and drugs can all lead to destructive organ lesions. Alcoholic pancreatitis is currently being observed more extensively and with increasing frequency in Central Europe.

     

Non monotonic morphometric changes produced at mouse neuromuscular junctions following in vivo stimulation at various frequencies

Summary Morphometric changes have been studied at the mouse neuromuscular junction (NMJ) as a function of the frequency of stimulation. In vivo stimulation was made at either 10, 25, 50 or 100 Hz. No significant change in the area of NMJ profiles is observed after stimulation. This indicates that stimulation does not change the volume of the nerve terminal. There is also no change of the volume density of mitochondria. However, there are significant reductions of the numerical density on area (N_A, number/m²) of the clear vesicles following stimulation at 25, 50 or 100 Hz. The N_A of clear vesicles is not further reduced following stimulation at 50 or 100 Hz than after the stimulation at 25 Hz. The numerical density on area of the coated vesicles was significantly increased following the stimulation at 25 Hz and 100 Hz. It is not increased more following stimulation at 50 Hz or 100 Hz than following stimulation at 25 Hz. One possible interpretation of the clear vesicle and the coated vesicle results is that less vesicles are liberated per sec by the NMJ with stimulation at 50 and 100 Hz than at 25 Hz because the action potential may fail to invade some terminal arborizations. The total surface density (i.e. surface of membrane in m² per m³ of nerve terminal) of the clear vesicles, the coated vesicles, the vacuoles and the presynaptic plasma membrane is not changed significantly following stimulation at any frequency. This indicates that there is no net loss of membrane at any of the frequencies investigated.This work is supported by grant from the Muscular Dystrophy Association of Canada     

Large scale preparation of hirudin

A process for large scale production of hirudin from whole leeches is described. Crude hirudin is prepared by aqueous extraction, adsorption and elution on/from bentonite and subsequently some other fractionation steps. Purification of crude hirudin is carried out by chromatography on Ecteola-cellulose followed by rechromatography on CM-Sephadex C-25 and Sephadex G 75. Homogeneity of the end product was tested by end group analysis and ultracentrifugation. The process presented here can be regarded as the first large scale preparation of hirudin.     

gamma,gamma'-(4,4'-Diamino-3,3'-biphenylylenedioxy)dibutyric acid (dicarboxidine) a safer substitute for benzidine type chromogens

gamma,gamma'-(4,4'-Diamino-3,3'-biphenylylenedioxy)dibutyric acid (dicarboxidine) is a new chromogen developed as a safe substitute for conventional benzidine type reagents. The compound is water soluble and has a low distribution ratio organic phase/aqueous phase, which makes it superior for use with automatic analytical instruments. The stability of both dicarboxidine and its coloured oxidized form are better than and their sensitivity equal to that of o-dianisidine. Dicarboxidine is not mutagenic in Ames test. Studies in mice for two years failed to reveal any carcinogenic activity, studies in rats indicated only a marginal effect.     

The “fluttering heart” and spatio-temporal characteristics of color processing—I: Reversibility and the influence of luminance

The classic phenomenon of the “fluttering heart” was investigated in two experiments. It was demonstrated that the effect consists of a genuine delay and not a phase difference. Its reversibility presents serious problems for two earlier explanations based on the dependence of perceptual latencies on wave-length and the differential latencies of the rod and cone apparatus, respectively. It was further shown that a luminance difference between target and background is neither a sufficient nor a necessary condition, but that a color difference is necessary. It was suggested that interactions between the color processing mechanisms across the chromatic border are involved.