Given an abstract, generate a keyword (a noun phrase) that best describes the focus or contribution of the paper. Such keywords can be directly from the given abstract or outside it.

Abstract: We describe the clinical and laboratory characteristics of 52 patients with rheumatoid vasculitis whose condition was diagnosed at a tertiary care center between 1974 and 1981, and we report their survival and the factors that were associated with decreased survival. The patients with rheumatoid vasculitis had decreased survival in comparison with an age-, sex-, and region-matched general population. Their survival was also decreased in comparison to that of an incidence cohort of community patients with rheumatoid arthritis. In the latter cohort, decreased survival was confined to those patients with classic but not definite rheumatoid arthritis. After partial correction for referral bias, we found no difference in survival between the cohort with rheumatoid vasculitis and the cohort with classic rheumatoid arthritis. We found that the age at diagnosis of rheumatoid vasculitis, the therapeutic decisions before and at diagnosis, and the referral distance were the best predictors of survival. Abnormal urinary sediment and hypergammaglobulinemia also predicted poor survival, but because of a lack of specificity in a small number of clinically abnormal values, we urge a cautious interpretation of their importance.
Adult

Abstract: Atlanto-axial rotatory fixation is one of a spectrum of rotatory abnormalities of the atlanto-axial joint. Rotatory fixation without anterior displacement of the atlas (Type I) has been reported in only a few cases in which there has been a prolonged interval between injury and diagnosis. The majority of these cases eventually required cervical fusion for persistent deformity or instability. Two cases are presented in which this diagnosis was made early with the aid of rotated odontoid radiographs, tomography and computerised axial tomography. Treatment by a short period of halter traction achieved reduction and early return of function. The authors conclude that early recognition and treatment of this rare condition may prevent the subsequent deformity and instability for which cervical fusion has been required.
Atlanto-Axial Joint

Abstract: The recognition of macromolecule abnormalities in various metabolic or immunologic related disease states has led to the use of plasma exchange for therapeutics. Limitations of plasma exchange, however, exist. Membrane plasma filtration provides a practical alternative. Solute removal can be made selective by the choice of operating conditions as temperature and the selection of the membrane/module design. The optimal temperature range is a function of the plasma type, solute concentrations and membrane system. Operation at below physiologic temperature (cryofiltration) is particularly suited for the removal of cold aggregative solutes, while operation at near or above physiologic temperature is more suited for the separation of solutes having large size differences at normal physiologic temperature. Membrane filtration is simple and safe to perform, is more selective than plasma exchange, does not require plasma product infusion and is more versatile than selective sorption in its applications.
Blood