Knemometry is the technique of choice for short-term growth studies, as it is the only anthropometric technique available that allows sufficiently accurate measurement of the lower leg (in anatomical terms, the leg) to enable changes in leg length to be detected over as short an interval as a week or less. The portable knemometer, like the Valk knemometer, essentially consists of two main parts: a rigid metal frame holding the footplate, measuring ruler and plateau and a moveable chair that moves on frictionless rollers on a track on the base of the frame. Unlike the Valk knemometer there is a standardized seat position for all subjects, making it easier and quicker to use. Assessment of technical error was done using mean coefficient of variation (CV) of lower leg length measurements done on the portable knemometer. Comparison of measurements made by two different observers was made by using percentage reliability. A small PR implies consistency between the two methods or observers being compared. Measurements from 164 visits were used to calculate the machine precision. Mean CV using all four measurements was 0.13% and using only three, having discarded the first, was 0.11%. Given a mean lower leg length of 246.3 mm for the children studied this translates to a machine precision of 0.32 mm if all four measurements are used and 0.27 mm if the last three measurements in the set are used. The mean difference in lower leg length between observers was 0.11 mm. Percentage reliability between the two observers for the portable knemometer was 0.03%. For comparison, PR for standing height and sitting height are 0.37% and 0.86% respectively. PR between the Valk and the portable knemometer was 0.04%.

Adult↗

PubMedDate not supplied

Identification of the Goodpasture antigen, alpha 3(IV) NC1, and four other NC1 domains of type IV collagen, by amino-terminal sequence analysis of human glomerular basement membrane separated by two-dimensional electrophoresis.

Two-dimensional (2-D) electrophoresis of collagenase-digested human glomerular basement membrane (GBM), containing the Goodpasture antigen, revealed a range of monomeric (24-30 kD) and dimeric (43-56 kD) subunits present across a pI range of 3-10. Five distinct alpha(IV)-chains were identified by amino-terminal sequence analysis of 18 of these components transferred to polyvinylidene difluoride membrane. The positions of the well-characterised 26-kD alpha 1(IV)-chain and 24-kD alpha 2(IV)-chain were confirmed. A highly cationic 28-kD monomer was identified as the alpha 3(IV)-chain, while more neutral 28-kD monomers were found to contain the alpha 4(IV)-chain. Sequences from neutral 26-kD monomers corresponded to the known cDNA sequence of the alpha 5(IV)-chain. The presence of charge isoforms of the alpha 1(IV)- and alpha 4(IV)-chains was confirmed by identification of several monomers with different pI but the same sequence. Sequence analysis of dimeric components demonstrated homodimers of alpha 1(IV), alpha 2(IV) and alpha 4(IV), and suggested the presence of heterodimers of alpha 3/alpha 5 and alpha 1/alpha 5. 2-D Western blots of human GBM, with anti-GBM autoantibodies, a monoclonal antibody (P1) to the Goodpasture antigen and a monoclonal antibody to the alpha 3(IV)-chain, demonstrated that the major autoantigenic epitope was localised to the alpha 3(IV)-chain, but that there was also reactivity with the alpha 4(IV)-chain.

Amino Acid Sequence↗