Bone morphogenetic protein 2 stimulates articular cartilage proteoglycan synthesis in vivo but does not counteract interleukin-1alpha effects on proteoglycan synthesis and content

OBJECTIVE: To study the effect of bone morphogenetic protein 2 (BMP-2) on articular cartilage proteoglycan (PG) synthesis in vivo and to investigate whether BMP-2 is able to counteract the effects of interleukin-1 (IL-1) on articular cartilage PG synthesis and content. METHODS: BMP-2 alone or in combination with IL-1alpha was injected into murine knee joints. PG synthesis was measured by 35S-sulfate incorporation using an ex vivo method or autoradiography. Cartilage PG content was analyzed by measuring Safranin O staining intensity on histologic sections. RESULTS: BMP-2 appeared to be a potent stimulator of articular cartilage PG synthesis in vivo. However, BMP-2 was not able to counteract the deleterious effects of IL-1alpha on articular cartilage PG synthesis and content. In addition, intraarticular injections of BMP-2 induced chondrophytes. CONCLUSION: Although BMP-2 is a very potent stimulator of cartilage PG synthesis in vivo, the therapeutic applications of BMP-2 are limited due to the inability of BMP-2 to counteract the effects of IL-1 and the induction of chondrophytes.     

Predictive value of magnetic resonance imaging and computerized tomography for conservative renal surgery in an ex vivo tumor enucleation study followed by step-sectioning

Two double-stranded RNA viruses exist as permanent persistent infections of the yeast Saccharomyces cerevisiae: ScVL1 and ScVLa. Both belong to the Totiviridae, which include a number of fungal and protozoan double-stranded RNA viruses. Although ScVL1 and ScVLa share the same genomic organization and mode of expression and coexist in the same cells, they show no evidence of recombination: with one limited exception, sequence conservation is detectable only in regions conserved in all totiviruses. Both have two open reading frames on their single essential RNAs: cap (encoding a capsid polypeptide) and pol (encoding an RNA-dependent RNA polymerase). The ScVLa virus, like ScVL1, appears to express its Pol domain by a -1 translational frameshift.     

Torque/velocity properties of human knee muscles: peak and angle-specific estimates

Angle-specific (AS) torque/velocity data have been used to avoid angle related variation in peak torque capacity. However, series elastic structures cause the contractile velocity of active force-producing tissue to differ from external joint velocity except at peak torque. Alternatively, angle related variation may be removed by normalizing peak torque to the isometric maximum at that angular position. The AS, peak (P), and normalized peak (NP) methods were compared in isovelocity knee flexion and extension at velocities between 50 and 250 degrees s-1 for 8 male subjects. The P and NP methods gave more similar torque/velocity relations than the AS method. Further, very little variation in peak torque was attributed to differences in joint angle. Both the P and AS methods illustrate that relative quadriceps/hamstrings torque capability (flexor/extensor ratio) increases slightly with velocity. It is proposed that antagonist muscle torque capabilities should be compared at different angular positions to assess muscular imbalance.     

Rapid Cauer filter design employing new filter model

The exact three-dimensional (3D) design of a coaxial Cauer filter employing a new filter model, a 3D field simulator and a circuit simulator, is demonstrated. Only a few iterations between the field simulator and the circuit simulator are necessary to meet a given specification     

Sizing of bovine heart and kidney pyruvate dehydrogenase complex and dihydrolipoyl transacetylase core by quasielastic light scattering

Quasielastic light scattering (QELS) measurements on several preparations of bovine heart and kidney pyruvate dehydrogenase complex yielded hydrodynamic radii (rH values) ranging from 25.7 to 30 nm. Gel filtration chromatography removed stable aggregates and generated preparations that gave essentially the same rH values of 24.3 +/- 0.6 nm for both complexes. The data were characteristic of a monodisperse system and agree with estimates using cryoelectron microscopy [Wagenknecht et al. (1991) J. Biol. Chem. 266, 24650-24656]. The equivalent hydrodynamic sizes for the heart and kidney complex indicate that the larger number of pyruvate dehydrogenase components in the heart complex (M(r) congruent to 9 x 10(6)) than the kidney complex (M(r) congruent to 7.5 x 10(6)) associate without radial expansion of the heart complex. That accommodation of additional mass is consistent with the space available since even in the more massive complex greater than 80% of the volume within the dimensions of the complex must be occupied by solvent. Preparations of the core of the complex are primarily composed of 60 dihydrolipoyl acetyltransferase (E2) subunits whose inner domains associate to form a pentagonal dodecahedron that is readily observed by electron microscopy (particle radius 10.7-11.3 nm). However, the bulk of E2's mass is present in an exterior multidomain structure. These mobile outer structures are very difficult to observe by standard electron microscopy techniques. Preparations of the core formed stable aggregates that were removed by gel filtration chromatography. QELS measurements gave an rH of 20.1 +/- 0.8 nm.(ABSTRACT TRUNCATED AT 250 WORDS)