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Paper chromatographic procedures may be used to detect cephalothin and its metabolite desacetylcephalothin in urine, plasma, synovial fluid, and cerebrospinal fluid. Protein-bound antibiotics are released from plasma, cerebrospinal fluid, and synovial fluid by dilution with an equal volume of dimethylformamide. Data are presented on the sample preparation, paper chromatographic system, and other specific techniques.

SummaryAfter treatment of human synovial fluid with hyaluronidase, the hyaluronate and proteins can be separated by paper electrophoresis. The electrophoretic distribution of the protein fractions of normal synovial fluid differs from that of the protein fractions of both normal serum and osteoarthritic synovial fluid.

The various lubrication regimes encountered in engineering are listed and the basic characteristics of each regime described. This survey covers hydrodynamic, elastohydrodynamic, mixed, and boundary lubrication conditions. The geometric, kinematic, and loading conditions in human joints are examined, and the basic properties of synovial fluid and articular cartilage, as the lubricant and bearing material respectively, noted. An assessment of the hydrodynamic, boundary, weeping, and elastohydrodynamic modes of operation which have been proposed as explanations of the performance of human joints is presented.

The work carried out applies to lubricated sliding surfaces in living and artificial human joints, with particular application to the hip, one of the principal load-bearing synovial joints in the body. Results are presented concerning the dimensions of the fluid-filled space between the articular surfaces of an unloaded human hip joint. The surface quality of articular surfaces has been assessed in a number of cases. Friction and lubrication experiments have been carried out on a reciprocating type of test machine using samples of articular cartilage and various artificial materials. It is hoped that the information gained from these experiments will lead to a clearer understanding of the load-carrying capacity of a human joint which is lubricated with synovial fluid.

Synovial fluid functions both as a lubricant and as a nutritive medium in joints. Its chemical composition suggests that it is a dialysate of blood plasma with the addition of the mucosubstance, hyaluronic acid. In addition the fluid contains a small cellular component. The quantities of some of the chemical components are apparently anomalous and need explanation. The hyaluronic acid, probably combined with a small amount of protein, is believed to be secreted by the cells lining the joint cavity, the synovial cells.The volume and naked eye appearance of the fluid vary from joint to joint in the same species and in the same joint from species to species. The volume of fluid that can be aspirated from normal human joints is too small for most chemical and physical investigations and recourse must be made to fluids from the larger domestic animals and to pathological human fluids.The most characteristic property of the fluid is its viscosity. This has been investigated using the Weissenberg rheogoniometer. This allows of a study of the viscosity and elasticity of the fluids at different shear rates. Results on fluid from both normal animal joints and pathological human joints will be presented. Their relevance in joint lubrication will be discussed.

SummaryThe dinitrofluorobenzene-reactive amino compounds of synovial fluid samples have been fractionated by paper chromatography and estimated quantitatively.The total amount of reactive amino groups increases with the clinical activity of disease, but cannot be correlated with the »class» or »stage». The proportions of the different fractions are also influenced by the severity of the disease.

An application of the colorimetric estimation of aminotripeptidase activity in synovial fluid is described, with respect to special features of this biological fluid. Suitable conditions, e.g. adequate degrees of dilution, buffer and pH of the reaction mixture were experimentally found. For the substrate GGG, a paper chromatographic method was elaborated, which makes it possible to estimate the enzyme activity also in small amounts. Methods applied to the study of aminotripeptidase activity in biological material are reviewed.

Immunological investigation of four patients with meningococcal meningitis who developed arthritis or cutaneous lesions showed circulating meningococcal antigen at the time of presentation in each patient. It was cleared from the circulation over the next few days. Circulating antibody was detectable in three of the four patients about a week after the onset of the illness. A marked fall in the serum C(3) level occurred in two patients at about that time. Deposits of meningococcal antigen, immunoglobulin, and C(3) were detected in the synovial fluid white cells of the two patients studied and in one of three skin biopsies examined. These findings suggest that the arthritis and cutaneous lesions of meningococcal meningitis may be due to immune complex formation.

Out of 717 patients with meningococcal disease 53 showed one or more of the three allergic complications: 47 (6·6%) developed arthritis, 12 (1·7%) developed cutaneous vasculitis, and 6 developed episcleritis. These complications, which were often multiple, occurred six to nine days after the beginning of the illness and three to six days after the start of successful antibiotic therapy. Those patients with severe systemic disease were prone to the complications. Histological and bacteriological study of the arthritis and vasculitis showed that these lesions were probably not due to persisting infection and suggested that they might be due to immune complex disease.

The possibility of complex formation between chloroquine and hyaluronate-protein has been investigated by a spectrophotomefric method. Interaction was observed between chloroquine and a hyaluronate-protein containing 3.4% protein, but no interaction occurred between chloroquine and hyaluronate-protein preparations containing 2.36 and 2.30% protein, respectively. The protein in two preparations appears to be tightly bound to the hyaluronate. The larger amount of protein in one of the preparations appears to be responsible for the binding process.

Ten min after the injection of [4- 14 C]cortisol in the synovial cavity of normal and arthritic knees of humans and horses, a sample of synovial fluid was aspirated, extracted with organic solvents, and fractionated into free and conjugated fractions. The free fraction accounted for 85% of the total extract of the normal synovium of humans and horses while in the arthritic knees this fraction amounted to 93 and 96% of the total radioactivity in synovial fluid extract. The radioactivity which corresponded to unconverted cortisol was 44 and 47% of the total radiometabolites in synovium of normal knees of human and horse, respectively, 80% in a human subject with rheumatoid arthritis, 6% and 1% in human and horse with osteoarthritis. The main transformation product of cortisol in human and horse in normal and arthritic joints was 11β-hydroxyandrostenedione. 11-Ketoandrostenedione and less polar metabolites were isolated. Unidentified highly polar metabolites were also detected. The relatively small percentage of radioactivity which corresponded to cortisol in osteoarthritic human and horse was accompanied by a considerable increase in the radioactivity which corresponded mainly to 11β-hydroxyandrostenedione. After 10-min intervals up to 2 h the quantities of cortisol metabolites are changeable. After 2 h, the percentage of 11β-hydroxyandrostenedione, 11-ketoandrostenedione and less polar metabolites decreased considerably while the percentage of compounds of greater polarity than cortisol increased.