Ligamentary structure of the base of the nail

Summary The authors report the results of 115 dissections of the base of the distal phalanx of fingers and toes. In 85% of cases including hypoplastic supernumerary digits, there is a connective ligament-like structure. It is a dorsal expansion of the lateral ligament of the distal inter-phalangeal joint arising from the intermediate phalanx and ending in the matrix and the lunula. This ligament may have a role in biomechanical strains on the nail. It can explain some dystrophic nails associated with some malpositioned joints in fingers or toes.

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Structure ligamentaire de la base de l'ongle

Résumé Les auteurs rapportent les résultats de 115 dissections portant sur la base de la phalange distale des doigts ou des orteils. Ils retrouvent dans 85 % des cas, y compris sur des doigts hypoplasiques surnuméraires, une formation conjonctive de type ligamentaire. Il s'agit d'une expansion dorsale du ligament latéral de l'articulation interphalangienne distale, naissant de l'extrémité distale de la phalange intermédiaire et se terminant au sein de la matrice et sur la lunule. Ce ligament ostéomatriciel peut jouer un rôle dans la transmission des contraintes biomécaniques sur l'ongle et expliquer les dystrophies unguéales stéréotypées associées à certaines malpositions articulaires des doigts ou des orteils.

     

Wallerian degeneration in a patient with Schilder disease: MR imaging demonstration

Wallerian degeneration in the corticospinal tract was demonstrated by magnetic resonance (MR) imaging in a patient with Schilder disease. The histochemical stages of myelin breakdown that allow its demonstration by MR imaging are reviewed.     

用细口径反相柱HPLC分离多种前列腺素

HPLC与放射性同位素联用,可同时分离鉴定多种花生四烯酸代谢产物。目前国外一般是使用普通口径(4.6 mm)的反相柱,以30%左右乙腈为流动相,流速为1～3 ml/min。这种HPLC方法乙腈用量较大,费用太贵,不适合国内实验室常规操作。据报道,细口径     

Childhood scoliosis: MR imaging

The spinal cords of 28 scoliosis patients between the ages of 1 month and 17 years were examined with magnetic resonance (MR) imaging. Complete visualization was obtained in all cases. In 15 patients (53%) neuropathologic abnormalities demonstrated by MR imaging significantly affected their clinical course, including tethered cords (n = 7), syringomyelia (n = 5), Arnold-Chiari I malformation (n = 4), spinal cord tumors (n = 2), Arnold-Chiari II malformation (n = 3), and diastematomyelia (n = 1). The advantages of MR imaging in the evaluation of the scoliotic spine in children include a high sensitivity for the occult conditions associated with scoliosis, good anatomic demonstration of the cord, and absence of bone artifacts. MR imaging is recommended as a primary imaging modality in scoliosis, following conventional radiography.     

Monoclonal antibody to human high-molecular-weight kininogen recognizes its prekallikrein binding site and inhibits its coagulant activity

We developed a mouse monoclonal antibody (MoAb 115-21) to human high- molecular-weight kininogen (HK) that recognizes its prekallikrein binding site (residues 565 through 595 of HK). The corresponding synthesized 31-amino acid peptide (peptide IV) was recently shown to retain native HK's prekallikrein binding property. The same peptide bound factor XI also, although less avidly. Our MoAb recognizes purified HK, peptide IV, and the light chain moiety of HK (where the peptide IV resides), as shown by enzyme-linked immunosorbent assay (ELISA) and Western blotting experiments. The apparent dissociation constant for the HK and MoAb 115-21 interaction was 2.2 nmol/L. It does not recognize low-molecular-weight kininogen (LK) with which HK shares its heavy chain moiety or any antigens in human plasma congenitally deficient in kininogens. The binding of MoAb 115-21 to purified light chain of HK was competitively inhibited by peptide IV. In addition, the antibody inhibits HK-dependent clotting activity of normal human plasma and dextran sulfate-mediated activation of prekallikrein in plasma and retards cleavage of HK in normal plasma after contact activation with dextran sulfate. Also, purified Fab fragments of MoAb 115-21 inhibited the HK-dependent coagulant activity and dextran sulfate-mediated prekallikrein activation in normal plasma. Since the kd for HK-MoAb 115- 21 interaction is ten times lower than that of HK-prekallikrein, our data suggest that binding of MoAb 115-21 to HK's peptide IV site increases the free prekallikrein concentration in plasma and thus results in the decreased efficiency of factor XIIa-mediated activation of prekallikrein. Decreased levels of kallikrein thus formed may be responsible for the inhibition of HK-dependent clotting activity and the decrease in rate and extent of HK cleavage in normal plasma on contact activation with dextran sulfate. MoAb 115-21 may thus prove very useful, especially with its high affinity for HK, in further delineation of the role of HK and prekallikrein in contact activation and kinin-related human pathology.