Conjuctivitis and keratoconjunctivitis associated with primary immunodeficiency diseases.

Nineteen patients with a variety of well-defined primary immunodeficiency diseases were examined for ocular abnormalities. Eight patients with low levels, or absence, of all the major serum immunoglobulins had conjunctivitis or keratoconjunctivitis associated with bacterial infection. The remaining 11 patients, who had at least one immunoglobulin class present in normal concentration in the serum, showed no inflammatory ocular lesion. Absence of only IgA, the major tear immunoglobulin, did not predispose the eye to these lesions.     

The lysis of crosslinked human fibrin by plasmin yields initially a single molecular complex, D dimer-E

Physicochemical and immunological comparisons between plasmin mediated crosslinked (XL) fibrin digests made in buffer, serum and buffered Trasylol systems have shown that all the D dimer released from XL fibrin is associated with the fibrin E fragment in a strong, non-covalent and electrophoretically stable complex which has the empirical formula, 2D-E. The complex dissociates and reassociates in the presence and absence of detergent. The subunits of D dimer moiety of the complex are made up of A chain remnants (MW 12, 000), Bβ chain remnants (42,000) and crosslinked γ chain remnants (MW about 80, 000). A diagram showing the locations of the three domains of the complex in three distinct fibrin subunits is presented. Aggregates of the complex were found in fibrin lysates made in human serum and their significance to fibrin lysis in vivo is discussed.     

Extrinsic control of intrinsic neuronal plasticity: An hypothesis from work on simple systems

All advanced nervous systems use plastic properties of neurons for learning remembering and achieving other information processing feats. Recent findings on a variety of relatively simple nervous systems or reduced parts of more complex ones suggest the notion that, in addition to having neurons with intrinsically plastic properties, nervous systems also have mechanisms for controlling the development, expression, and maintenance of changes in their inherently malleable neurons. This hypothesis has important implications for understanding both the brain's learning machinery and also aspects of nervous system organization not obviously related to learning.