On the Biochemistry of Skin, and the Chemical Basis of Skin Swelling.
IN previous investigations by the authors [1924] it has been shown that the swelling of a fibrous tissue, such as skin, depends on both structural and chemical factors. The chemical factors considered were those due to variation in the external swelling medium. There remain those contributed by the skin itself. The influence of these is well shown by comparing the swelling of fresh goat skin with that of commercial sun-dried goat skin. The drying of the skin at a tropical temperature has caused a chemical change in its proteins which is made visible by the firm cementing together of the fibrils of the fibres. Skin is composed chiefly of proteins, though it contains in addition fats, sterols, and sterol esters. Rosenthal [1916] gives the following analysis of calf skin dried in vacuo at 55-60°.
Verlauf der Quellung bei Kollagen
ZusammenfassungDie Quellung von Kollagen wird vor allem von den nach außen wirksamen Überschußladungen bestimmt. Alle Maßnahmen zur einseitigen Hervorhebung der negativen oder positiven Ladungen wie: Entfernung vom I. P. oder einseitige Veränderung bzw. Blockierung polarer Gruppen sind deshalb quellungsauslösend.In der Nähe des I. P. führt die einheitliche Belegung mit Na⊕- oder K⊕-Ionen unter den hoch verdünnten Elektrolytlösungen oder unter Wasser zur zweidimensionalen innerkristallinen Quellung.Bei der Abschirmung der polaren Gruppen durch Gegenionen entstehen diffuse Doppelschichten, die eine Aufteilung der Fibrillen in einzelne Protofibrillen ermöglichen.Verdrängung der diffusen Doppelschichten durch Zusatz von Elektrolytlösungen höherer Konzentration bewirkt Entquellung der Fasern. Die Entquellung der Fibrillen, d. h. ihre Rekristallisation, ist aber wegen zu kurzer Assoziationszeiten nur unvollständig.Die Bindung zweiwertiger Kationen dürfte größtenteils äquimolar erfolgen und führt infolge Quervernetzung von Protofibrillen zu 80–100 Å dicken Längseinheiten. Quellung erfolgt erst zwischen diesen Vernetzungsprodukten.Die Einlagerung langkettiger anionenoder kationenaktiver Verbindungen verursacht infolge einer intrafibrillären Aufweitung das Eindringen von Quellungsflüssigkeit.
Immunization with Brucella melitensis Rev 1 against Brucella ovis infection of rams.
The efficacy of Brucella Melitensis Rev 1 vaccine (Rev 1) for the prophylaxis of Brucella ovis ram epididymitis was evaluated. Twenty-nine 3-month-old rams were vaccinated with 2 X 10(9) Rev 1 and 14 were revaccinated with 5 X 10(8) at 14 months of age. Six rams remained unvaccinated as a control group. All rams were challenged with 5 X 10(8) B. ovis at 21 months of age. Before being slaughtered 8 weeks later, only one vaccinated ram developed epididymitis while four of the six control rams developed testicular alterations. Genital and selected extragenital organs and lymph nodes were removed at slaughter and inoculated on selective media. B. ovis was isolated from 26.6% of the vaccinated rams, 21.4% of the revaccinated rams and 100% of control rams. Portions of epididymis, testes and vesicular glands were also used for pathological studies. More severe lesions were observed in control rams than in vaccinated ones. In conclusion, these results show that vaccination of young lambs, followed or not by revaccination, is a suitable method for the prophylaxis of B. ovis infection of rams.