Effect of medial arch-heel support in inserts on reducing ankle eversion: a biomechanics study

Background  

Excessive pronation (or eversion) at ankle joint in heel-toe running correlated with lower extremity overuse injuries. Orthotics and inserts are often prescribed to limit the pronation range to tackle the problem. Previous studies revealed that the effect is product-specific. This study investigated the effect of medial arch-heel support in inserts on reducing ankle eversion in standing, walking and running.     

Expression of mouse cytochrome P450IA1 cDNA in repair-deficient and repair-proficient CHO cells.

Recombinant DNA techniques have been used to develop Chinese hamster ovary cell lines for studying chemically induced genotoxicity. These cell lines express a specific cytochrome P450 isozyme responsible for the metabolism of polycyclic aromatic hydrocarbons and exhibit defined differences in DNA repair capacity. A bacterial gene (neo) conferring resistance to gentamicin was inserted into the pcD expression vector containing the mouse cytochrome P1450 (P450IA1) cDNA to facilitate the selection of transformed cells. This plasmid was introduced into the nucleotide-excision-repair-deficient UV5 cell line by electroporation. Transformed clonal isolates expressing the P1450 cDNA were identified by differential cytotoxicity assays using benzo[a]pyrene (B[a]P). One such clone, termed UV5P1, was mutagenized with ethyl methanesulfonate and selected for resistance to killing by UV radiation to derive a repair-competent clone that expresses similar P1450 activity to that of the parental cell line. Two repair-competent clones were selected and called 5P1R1 and 5P1R3. The resulting cell lines (UV5P1, 5P1R1, and 5P1R3) expressed arylhydrocarbon hydroxylase activity. UV5P1 and 5P1R3 were compared in terms of cytotoxicity and mutagenicity after exposure to B[a]P. Induced mutations were measured at the adenine phosphoribosyltransferase (aprt) and hypoxanthine guanine phosphoribosyltransferase (hprt) loci. Repair-deficient UV5P1 cells were killed by B[a]P at concentrations below 0.1 microM, while the repair-proficient 5P1R3 cells showed no toxicity up to 60 microM. Mutation induction at both loci was also much more efficient in UV5P1 cells. These new cell lines provide a more sensitive system that can be used in a battery of assays to evaluate the genotoxicity of chemicals requiring P450IA1 metabolic activation and to assess the role of DNA repair in modulating the biological effects of DNA damage.     

Effect of air abrasives on marginal configurations of porcelain-fused-to-metal alloys: an SEM analysis

Air abrasion of castings for metal ceramic crowns is a routine procedure in ceramics laboratories for cleaning, seating, and preparing casts for porcelain application. This technique can result in damage to the margins of castings. This investigation evaluated the extent and significance of this procedure. Marginal abrasion ranged from 5 to 110 microns. ANOVA, followed by Tukey's post hoc evaluation revealed no difference between abrasives, but significant differences were noted among alloys and margin configurations (p less than 0.05). Marginal loss by alloy was as follows: [Jelenko O] greater than [Olympia = Cameo] greater than [Jelstar] greater than [Genesis II]. Marginal loss by marginal configuration was as follows: [beveled shoulder] greater than [chamfer = shoulder]. Significant marginal damage can occur during air abrasion of dental castings.     

Pulpal response to chemically cured and experimental light-cured glass ionomer cavity liners

This investigation evaluated the effects of an experimental light-cured glass ionomer (LCGI) cavity liner and chemically cured Ketac-Bond glass ionomer restorative material on the pulpal tissues of monkeys. Class V cavities were prepared in 71 teeth of three adult Macaca mulatta monkeys at 7- and 35-day intervals. Ketac-Bond or LCGI cavity liners were placed in cavities with the smear layer intact (groups I and II) or with the smear layer removed (groups III and IV) and were restored with composite resin. Tissues were acquired, sectioned at 7 microns, stained for microscopic evaluation, or prepared for SEM evaluation. No statistically significant differences between materials existed at either time interval, regardless of smear layer presence. Histopathologic results demonstrated minimal pulpal reactions for groups I through IV. SEM analysis showed tenacious bonding of the LCGI material to prepared cavity walls, with absence of contraction gap formation. The results indicated excellent pulpal responses to both materials.     

Immunoadsorption for coagulation factor inhibitors

Inhibitors to coagulation factors are among the most difficult problems in the management of coagulation disorders. Most presently available therapy does not assure hemostasis. An extracorporeal immunoadsorption system, which selectively binds IgG, was used to lower inhibitor levels in eight patients on 10 occasions. In this system, separated plasma is delivered to two staphylococcal protein A-Sepharose columns, which are coupled to an elution monitor. Columns are eluted sequentially and regenerated to maximize IgG removal. Successful removal of the inhibitor was accomplished in all six hemophiliacs on seven occasions, as well as in a patient with acquired von Willebrand disease. All patients whose inhibitors were lowered to less than 10 Bethesda units achieved measurable factor levels when factor concentrate replacement was given. Immunoadsorption facilitates efficient removal of inhibitors, which allows factor replacement therapy.     

A double-blind provocative study chocolate as a trigger of headache

A provocative double blind study of headache was performed using chocolate as the active agent and carob as the placebo. The chocolate and carob samples were formulated to duplicate products used in an earlier study (1) in which strong differential effects between the ability of chocolate and carob to trigger headache in migraine were shown. Sixty-three women with chronic headache (50% migraine, 37.5% tension-type, 12.5% combined migraine and tension-type) participated in the study. After 2 weeks of following a diet that restricted vasoactive amine-rich foods, each subject underwent double-blinded provocative trials with two samples of chocolate and two of carob presented in random order. Diaries were maintained by the subjects throughout the study, monitoring diet and headache. The results demonstrated that chocolate was not more likely to provoke headache than was carol in any of the headache diagnostic groups (²(2) 0.36, p =0.83). Interestingly, these results were independent of subjects' beliefs regarding the role of chocolate in the instigation of headache (²(1)=0.73, p =0.39). Headache diagnosis and the concomitant use of additional vasoactive amine-containing foods were also not associated with chocolate acting as a headache trigger. Thus, contrary to the commonly held belief of patients and physicians, chocolate does not appear to play a significant role in triggering headaches in typical migraine, tension-type, or combined headache sufferers.