To obtain more information concerning the origin of dendritic reticulum cells, the development of germinal centers in the spleens of rabbits was investigated by conventional light microscopy, enzyme histochemistry, and electron microscopy. Washed sheep erythrocytes were used as antigen. Splenic tissue was examined on the 13th, 18th, 21st, 27th and 48th day after antigen administration. Electron microscopic investigations revealed transitional forms between typical fibroblastic reticulum cells, which formed the framework of the entire splenic white pulp, and typical dendritic reticulum cells. During this transformation, the enzyme histochemical pattern of alkaline phosphatase disappeared and a positive alpha-naphthylacetate esterase reaction appeared in the transformed cells. On the basis of these findings, it is highly likely that dendritic reticulum cells develop through transformation of fibroblastic reticulum cells during the development of germinal centers in rabbit spleens. The characteristic folding of the surface membrane of dendritic reticulum cells is probably caused by the conspicuous increase in size of the Golgi apparatus, the detachment of vesicles, and the uptake of such vesicles by the cell membrane observed electron microscopically during the cellular transformation. Receptors that are of significance in antigen trapping might reach the cell surface in this manner, i.e., with the Golgi vesicles.

No abstract

A new operative method of treatment of prolaps of pars membranacea in the region from trachea is reported. One cause of this prolaps is a false breathing mechanism, mainly without respiration through the nose. The reflection of pathogenesis of this special form of asthma, the operative treatment and therapy are described.

Zusammenfassung. Im Kreiskrankenhaus Freudenstadt wurden bisher fiber 50 Speichenbrfiche und Speichenstfickbrfiche des handgelenksnahen Speichenendes transartikul~ir mit einem Midifixateur externe immobilisiert. Frische Frakturen lassen sich durch Zug an dem das Handgelenk umgebenden Bandapparat in gute Repositionsstellungen bringen. Der Fixateur externe transartikular angebracht, kann diese guten Repositionsergebnisse exakt und fiber lange Zeit halten. Das operative Vorgehen wird aufgezeigt und an Behandlungsbeispielen die Leistungsf'~ihigkeit dieses Verfahrens demonstriert.Summary. Treatment with the fixateur externe is indicated in: rupture and luxation of the symphysis and sacroiliac joint; dislocated fracture with symphysiolysis and parailiosacral fractures or anterior pelvic fracture with dislocation of the sacroiliac joint; vertical fractures of the pelvis (Malgaigne). The operative technique with an additional Schanz screw, supra-acetabular and special installation of the external fixation, complications and experiences in the treatment of 35 patients are discussed.

From November 1974 to June 1978 60 severely injured car-occupants wearing seatbelt were treated at the department of surgery, University of Kiel. Ten of them sustained pelvic fractures. The cause of the injury was a direct pelvic trauma from the crashed car in 6 passengers. The maximum load on the pelvis was exceeded by the seatbelt during the delay of the car only in 4 patients. Contrary to the trauma by the lap-belt with abdominal-, lumbar spine, and pelvic injuries (seatbelt-syndrome by Garrett and Braunstein [5]) we found car-occupants with a threepoint-seatbelt injuries of the thorax, of the head with facial fractures and rarely with cerebral trauma, and of the legs with tarsal fractures. In our cases and in the literature pelvic fractures of car-passengers, who are wearing threepoint-seatbelts, are rare.