[Lumbar puncture--the post-puncture syndrome. Prevention with an "atraumatic" puncture needle, clinical observations]

Postlumbar puncture syndrome (PPS) is caused by continuous leakage of CSF through the dural puncture defect. While it has long been known that the symptoms are dependent on the diameter of the puncture needle, the influence of the needle point on the frequency of PPS has now also been examined. Following diagnostic and/or therapeutic lumbar puncture (LP) with Sprotte's "atraumatic" needle, the symptoms in 600 patients during a period of 8 days were recorded. In 92% of the patients LP involved no problems. In 7% the puncture was successful only at the second or third attempt. In 4 cases it was necessary to carry out the procedure under X-ray control. While the literature shows that PPS following lumbar puncture with a 21 G needle occurs in 30-40% of cases, only 3.6% of the patients complained about position-dependent headaches where the Sprotte needle was used. Nausea, dizziness and tinnitus were extremely rare (< 1%).--The "atraumatic" puncture needle reduces the frequency and the degree of PPS to the minimum and makes the lumbar puncture procedure possible on an outpatient basis.

A simple and inexpensive high density dialysis tubing cell culture system for the in vitro production of monoclonal antibodies in high concentration

This paper describes the construction and application of a low-cost roller bottle-like culture appliance in which hybridoma cells can be cultivated in high density in dialysis tubing. The appliance facilitates the simultaneous culture of up to four cell lines yielding 50 ml culture volume of each. Samples for follow-up analysis of the cultures can easily be taken when needed through sample ports. In order to obtain high cell densities (at least 10(7) cells/ml), high cell viability (at least 50%) and high antibody yield (at least 1.0 mg/ml) the bottle is rolled at a speed of 4-6 rpm and is gassed continuously by a micropump driven by rechargeable NiCd batteries fixed to the culture flask. Depending on the individual properties of the hybridoma lines tested, the cells may be cultured for 1-2 weeks, and cell densities of up to 30 x 10(6) cells/ml with viabilities of approximately 50% and monoclonal antibodies in concentrations of up to 2.8 mg/ml may be obtained. In their properties the monoclonal antibodies produced by this in vitro procedure are indistinguishable from those prepared in the form of conventional stationary culture supernatant or of ascitic fluid. Specific antibody content is within the same range as in ascitic fluid. Consequently, the monoclonal antibodies can be purified in one step, e.g., by ion exchange chromatography from the culture supernatant. Therefore, the newly developed culture device and the culture method described is a useful alternative to ascites production in live mice.

The role of von Willebrand factor multimers and propeptide cleavage in binding and stabilization of factor VIII

von Willebrand factor (vWF) is a multimeric glycoprotein that promotes platelet aggregation and stabilizes coagulation factor VIII in the plasma. vWF is also required for the stable accumulation of recombinant factor VIII secreted from cells in a heterologous expression system. In this report, we show that vWF can promote the in vitro reconstitution of factor VIII activity from dissociated heavy and light chains of factor VIII, suggesting that vWF may act to promote stable assembly of factor VIII subunits at the site of secretion. The structural requirements for vWF propeptide cleavage and for vWF multimerization in its binding and stabilization of factor VIII was examined using specifically altered recombinant vWF. The mutant vWF molecules were also assayed for their function in ristocetin-induced platelet agglutination mediated through the platelet receptor GPIb. Deletion of the vWF propeptide produced a dimeric vWF molecule that failed to mediate platelet agglutination, suggesting that multimerization is required for vWF to attain functional GPIb binding. This mature dimeric form of vWF, however, was fully capable of binding to and supporting stable secretion of factor VIII. A vWF mutant with an altered propeptide cleavage site formed large multimers of uncleaved pro-vWF that functioned in platelet agglutination. However, this noncleavage mutant neither bound to or supported stable accumulation of factor VIII. Analysis of the vWF propeptide, expressed independently, demonstrated that it could not bind factor VIII or stabilize its secretion. These results show that the dimeric mature vWF subunit is sufficient to bind and stabilize factor VIII and that the presence of uncleaved vWF propeptide inhibits both factor VIII binding and stabilization.