Retention of Blinding at Follow-Up in a Randomized Clinical Study Using a Sham-Control Cervical Manipulation Procedure for Neck Pain: Secondary Analyses From a Randomized Clinical Study

Objective

Participants in clinical trials of spinal manipulation have not been rigorously blinded to group assignment. This study reports on secondary analyses of the retention of participant blinding beyond the immediate posttreatment time frame following a single-session, randomized clinical study. A novel control cervical manipulation procedure that has previously been shown to be therapeutically inert was contrasted with a typical manipulation procedure.

Methods

A randomized clinical study of a single session of typical vs sham-control manipulation in patients with chronic neck pain was conducted. Findings of self-reported group registration at 24 to 48 hours posttreatment were computed. The Blinding Index (BI) of Bang et al was then applied to both the immediate and post–24- to 48-hour results.

Results

Twenty-four to 48 hours after treatment, 94% and 22% of participants in the typical and control groups, respectively, correctly identified their group assignment. When analyzed with the BI of Bang et al, the immediate posttreatment BI for the group receiving a typical manipulation was 0.22 (95% confidence interval [CI], − 0.03 to 0.47); for the group receiving a control manipulation, it was 0.19 (95% CI, − 0.06 to 0.43). The BI at post-24 hours was as follows: typical = 0.75 (95% CI, 0.59-0.91) and control = − 0.34 (95% CI, − 0.58 to − 0.11).

Conclusions

This study found that the novel sham-control cervical manipulation procedure may be effective in blinding sham group allocation up to 48 hours posttreatment. It appears that, at 48 hours posttreatment, the modified form of the typical cervical manipulation was not. The sham-control procedure appears to be a promising procedure for future clinical trials.     

Topology of Kell blood group protein and the expression of multiple antigens by transfected cells

Kell is one of the major blood group systems in human red blood cells (RBCs). The Kell antigens are carried on a 731 amino acid glycoprotein that is thought to span the erythrocyte membrane once. Rabbit antibodies to three synthetic peptides, derived from different parts of the Kell protein, were used to determine the topology of Kell protein on the RBC. Antibodies to a C-terminal peptide and to a peptide derived from amino acid residues 410 to 439 reacted with RBCs treated with 0.2 mol/L dithiothreitol. An antibody to the N-terminal peptide reacted with inside-out RBC vesicles but not with right-side-out vesicles nor with intact RBCs, showing that Kell is a type II membrane protein and that the extracellular portion of the protein is folded by disulfide bonds. By transfection, Kell protein was expressed on the cell surface of surrogate cells, and the transfected cells expressed similar antigenic properties as native RBCs. Kell protein was expressed in COS- 1 and K562 cells and in Sf9 cells infected by the Baculovirus system. Transfected K562 cells expressed several high-incidence antigens but not the low-incidence antigen K1.     

CD18-dependent and L-selectin-dependent neutrophil emigration is diminished in neonatal rabbits

Human neonatal neutrophils manifest decreases in mobility, adherence, and emigration compared with adult neutrophils that may contribute to the increased susceptibility of neonates to infection. In a developmental rabbit model, we show a reduced ability of neutrophils from 1-day-old rabbit pups to emigrate to inflamed peritoneium (3.7 +/- 0.35 x 10(6) neutrophils/mL peritoneal exudate) compared with 14-day- old (8.5 +/- 0.7 x 10(6)/mL) and adult rabbits (9.4 +/- 1.4 x 10(6) mL, P < .05) despite significantly increased blood neutrophil counts. Because the reductions in functional Mac-1 (CD11b/CD18) as well as the amount of surface L-selectin are hypothesized to be primarily responsible for the differences in human neonatal neutrophil mobility, we examined CD11b/CD18 and L-selectin in our model. Using flow cytometric analysis we found that similar to human neonates, neutrophils from 1-day-old rabbit pups had 57% of adult rabbit levels of L-selectin and, in contrast with adults, failed to show significant decreases in L-selectin after chemotactic stimulation. In addition, neutrophils from 1-day-old pups compared with adults showed a significantly diminished capacity to upregulate CD11b/CD18 after chemotactic stimulation in vitro, or after emigration to the inflamed peritoneum. Systemic administration of anti-L-selectin monoclonal antibody (MoAb) resulted in significant reduction in peritoneal neutrophils in adult (47%, P < .05) and 14-day-old rabbits (47%, P < .05), but was without effect in 1-day-old rabbits. Administration of anti-CD18 MoAb resulted in significant reduction in peritoneal neutrophil accumulation in all age groups though less in 1 day and 14 day (58% and 65%, respectively) than in adults (91%, P < .05). Only in the 14-day-old rabbits was there an additive effect of anti-L-selectin and anti-CD18 MoAbs compared with anti-CD18 alone (84% v 65%, P < .05). The findings in this in vivo rabbit model support the hypothesis that the previously described in vitro defects in human neonatal L-selectin and CD11b/CD18 may be major contributors to human neonatal inflammatory deficits.