Design, synthesis and structure of a zinc finger with an artificial beta-turn.

We have incorporated a bicyclic beta-turn mimetic (BTD; beta-turn dipeptide) into a zinc finger, creating a zinc finger with an artificial beta-turn. The designed peptide chelates zinc and has the same fold as the unmodified native zinc finger (finger 3 of the human YY1 protein). A combination of 1H NMR and structure calculations reveals that, in solution, this zinc finger has a fold similar to the known wild-type crystal structure and to other zinc fingers containing the consensus sequence X3-Cys-X4-Cys-X12-His-X3-His-X. The peptide was designed with BTD between the chelating cysteine residues, with BTD forming a type II' beta-turn linking the two strands of a distorted anti-parallel beta-sheet. The C-terminal portion of the peptide forms a helix with zinc co-ordinating histidine residues on successive turns of the helix. This work represents a step towards developing methods by which parts of a target protein may be replaced by peptide mimetics.

Staff nurse leadership and professional growth in the mentor role.

Nurses frequently commit only for a short term to medical/surgical nursing to pursue opportunities in more specialized areas. The implementation of a mentorship program for orientation incorporates professional role development and leadership opportunities for the staff nurse serving in the mentor role. The mentorship has resulted in a mutually beneficial mentor-orientee relationship. Practical triumphs for a successful mentorship as well as ongoing challenges are identified.

Immunohistochemical demonstration of proteinase inhibitor alpha-1-antichymotrypsin in normal human central nervous system.

The presence of alpha-1-antichymotrypsin, a serine proteinase inhibitor with a high affinity for cathepsin G, is demonstrated in the normal human central nervous system (CNS) by immunohistochemical techniques. Paraffin-embedded normal human CNS tissue from five adult, two fetal, one neonatal and three newborn autopsies were stained with monospecific rabbit antibodies to human alpha-1-antichymotrypsin using biotinylated goat anti-rabbit antibodies and an avidinbiotin-peroxidase complex. Positive immunostaining was seen in neurons and glial cells in the cerebral cortex, basal ganglia, hippocampus, cerebellum, brainstem, and spinal cord of the adults. The epithelium of the adult choroid plexus had the most intense staining in apical granular organelles corresponding in position to lysosomes or secretory granules. Ependymal cells, particularly those near the choroid plexus, were immunostained. The fetal CNS had no alpha-1-antichymotrypsin staining. Limited staining of choroid plexus, ependyma, and frontal lobe was found in the newborns. Immunostaining in the neonatal temporal lobe was only found in the choroid-plexus epithelium. These observations establish a widespread distribution of this proteinase inhibitor in the normal human CNS. Developmental regulation of this inhibitor in the human CNS is also indicated.

Beneficial effect of increased dietary linoleate upon in vivo platelet function in man.

The effect of increasing dietary linoleate upon in vivo platelet aggregation and disaggregation in 20 males and 46 female adult humans was studied. In creasing exogenous linoleate for 2 weeks from 2.89 +/- 0.11 to 5.00 +/- 0.26% of energy was associated with the doubling of the aggregation time and halving of the disaggregation time. Decreasing dietary linoleate in the following 2-week feeding period was associated with a reversal of the effect.

Titrating dietary linoleate to in vivo platelet function in man.

Platelet aggregation time significantly increased within 48 hours in response to an increase in dietary linoleate of 4% of calories while disaggregation time decreased significantly in 96 hours. A change as small as 0.5% of calories was associated with significant alterations within 4 days. In this group, dietary linoleate appears to be related to platelet function by the equations Aggregation time equals 41.14 plus 2.79 linoleate Disaggregation time equals 11.04 minus 25.52 linoleate.