Oral administration of caffeine metabolite 7-methylxanthine is associated with slowed myopia progression in Danish children

PURPOSE

Myopia is associated with an increased risk of permanent vision loss. The caffeine metabolite 7-methylxanthine (7-MX), licensed in Denmark since 2009 as a treatment to reduce the rate of childhood myopia progression, is the only orally administered therapy available. The purpose of the current study was to assess the rate of myopia progression in children taking 7-MX.

METHODS

Longitudinal cycloplegic refraction and axial length data for 711 myopic children from Denmark treated with varying doses of oral 7-MX (0-1200 mg per day) were analysed using linear mixed models.

RESULTS

The median age at baseline was 11.1 years (range 7.0 -15.0 years). Children were followed for an average of 3.6 years (range 0.9-9.1 years) and the average myopia progression was 1.34 dioptres (D) (range -6.50 to +0.75 D). Treatment with 7-MX was associated with a reduced rate of myopia progression (p<0.001) and axial elongation (p<0.002). Modelling suggested that, on average, an 11-year-old child taking 1000 mg 7-MX daily would develop -1.43 D of myopia over the next 6 years, compared with -2.27 D if untreated. Axial length in this child would increase by 0.84 mm over 6 years when taking a daily dose of 1000 mg of 7-MX, compared with 1.01 mm if untreated. No adverse effects of 7-MX therapy were reported.

CONCLUSIONS

Oral intake of 7-MX was associated with reduced myopia progression and reduced axial elongation in this sample of myopic children from Denmark. Randomised controlled trials are needed to determine whether the association is causal.

The wound healing effect of local leukocyte platelet-rich plasma after total hip arthroplasty: A randomized controlled trial

Rapid wound closure is important after arthroplasty procedures to prevent postoperative complications. Platelets are rich in growth factors and leukocytes contribute to innate immunity. We hypothesized that topical leukocyte platelet-rich plasma (L-PRP) derived from the blood of patients would be beneficial to wound healing. In this randomized controlled trial, patients subjected to elective total hip arthroplasty (THA) were assigned by concealed allocation either L-PRP application onto the sutured fascia or no application (control) after the THA intervention. In addition, all patients received 1.5 g protein/kg, 5 g L-arginine, 500 mg vitamin C and 44 mg zinc daily over the 4-week postoperative period to obtain optimal nutrition. The primary endpoint was complete healing of the skin incision. The secondary endpoints were blood transfusions, length of hospital stay, pain and wound infections. Sixteen patients in the L-PRP group and 17 patients in the control group completed the trial. L-PRP treatment accelerated complete wound healing after 3 weeks (seven in the L-PRP group vs. zero in the control group, p = 0.003) and after 4 weeks (12 in the L-PRP group vs. six in the control group, p = 0.037). No postoperative superficial wound infections occurred within 4 weeks, and there were no significant differences in the other secondary outcomes. L-PRP generated in 10 sex-matched healthy volunteers revealed increased concentrations of platelets (5.8-fold) and leukocytes (2.3-fold) compared with those in whole blood. Furthermore, the concentration of keratinocyte mitogen epidermal growth factor in L-PRP (380 ± 130 pg/ml, mean ± SD) was higher (p < 0.001) than that in serum (130 ± 26 pg/ml). In conclusion, a single intraoperative local application of L-PRP promoted wound healing after THA, possibly mediated by EGF receptor agonists.

False profile view is independently associated with serum metal levels in patients with metal-on-metal hip arthroplasty

PURPOSE

Elevated levels of serum metal ions can be found in some patients with metal-on-metal (MoM) hip replacements. This study seeks to identify whether there is a significant association between the contact patch to rim distance (CPRD) and the anterior center edge angle (ACEA), respectively, and serum cobalt (Co) and chromium (Cr) levels in patients treated with unilateral MoM hip replacements by using standing anteroposterior and false profile view radiographs.

METHODS

This is a retrospective analysis on 53 patients with either unilateral ReCap or M2a-Magnum MoM hip replacements operated in 2006 or 2007. Univariate linear regression and multivariable linear regression (MLR) analyses were performed using the CPRD and ACEA along with risk factors for elevated serum levels of Co and Cr previously suggested in the literature as explanatory variables. Serum Co and Cr were measured using inductively coupled plasma mass spectrometry.

RESULTS

The MLR model showed that the same three variables (gender, CPRD and ACEA) were significantly associated with serum levels of both Co and Cr explaining approximately half of the variation. A univariate analysis showed a polynomial association between both anteversion angle and the ACEA with serum levels of Co and Cr. The vertex of the polynomial function was located at approximately 20° and 40°, respectively.

CONCLUSION

Gender, CPRD and ACEA are independently associated with serum levels of Co and Cr. Both ACEA and anteversion angles have optimae associated with low serum metal levels which may be useful for post-surgery evaluation of cup positioning.

Clinical Performance of the ASR and ReCap Resurfacing Implants—7 Years Follow-Up

We perform a non-randomized, consecutive pilot study on the ASR and ReCap resurfacing hip implants and have completed 7 years follow-up. Forty-six non-osteoporotic patients with hip osteoarthritis and anatomical conditions suitable for resurfacing were divided into 2 equal groups and operated sequentially, starting with the ASR implants. Sixteen patients operated with ASR and 19 patients with ReCap have been followed-up. There were no significant differences between the two groups preoperatively as to physical function, pain, or femoral BMD. The serum concentrations of cobalt and chromium were higher in the ASR group from 1/2 to 7 years postoperatively. Five of 16 ASR implants have been revised, and none of the ReCap implants. BMD below the femoral component increased in both groups.

Cytokine measurements and possible interference from heterophilic antibodies--problems and solutions experienced with rheumatoid factor

Cytokines are important in the understanding of the immune process in health and disease and are valuable indicators in diagnostics. Measurements of cytokines are based on immunometric methods, and it is important to understand possible pitfalls in these methods to produce reliable cytokine data. This paper focuses on obtaining optimal measurements when applying enzyme-linked immunosorbent assay (ELISA) or multiplex immunoassays (MIA). Cytokines are measured in serum or plasma, as well as in various other body fluids, all containing a series of antibodies and the possibility of interference from these. Some antibodies, such as heterophilic and human anti-animal antibodies, are able to interfere with all immunoassays, but the immunometric techniques are most prone to serious interference from this source. Another type, rheumatoid factor (RF) is a composite of different autoimmune antibodies which can be present in both blood and synovial fluid. RF is present in some arthritic diseases as well as in some other medical conditions. When present, especially RF IgM is known to interfere with the immunometric measurements. A possible and affordable solution to diminish this interference is PEG precipitation, but other efficient, but more expensive, methods, such as precipitation using Protein L or commercially available blocking agents, are also available. Interference of RF is at present not tested in all cytokine assays, but degree of interference from RF, human anti-animal and heterophilic antibodies, as well as from other possible disease-specific antibodies, must always be considered when developing and applying new assays for cytokine measurements.

Differential effects of decoy receptor- and antibody-mediated tumour necrosis factor blockage on FoxP3 expression in responsive arthritis patients

Our aim was to clarify if anti-tumour necrosis factor (TNF) drugs have effect on expression of three splice forms of FoxP3 mRNA in blood CD4+ T cells from rheumatoid arthritis (RA) patients compared with healthy controls. Forty-five rheumatoid arthritis patients treated with anti-TNF therapy were investigated in a 12-week prospective cohort study. FoxP3 isoforms, CD25 and CTLA-4 mRNA in blood CD4+ T cells were measured with quantitative real-time PCR. Patients benefitting from the treatment, based on changes in DAS28 scores, revealed a significant decrease in expression of full-length FoxP3 following 12 weeks treatment with TNF receptor 2 fusion protein (Etanercept), but not following treatment with anti-TNF antibodies (Adalimumab or Infliximab). A partial normalization of the CTLA-4/FoxP3fl ratio and a correlation between clinical improvement and change in FoxP3 mRNA expression were also seen in Etanercept responders. These changes were not observed in responsive patients treated with the antibody therapies. Our data suggest that TNF decoy receptor and anti-TNF antibodies differ in their effect on FoxP3 expression in responsive patients. As Etanercept binds both TNF-α and Lymphotoxin-α (LT-α), whereas the antibodies only target TNF-α, LT-α may regulate FoxP3 expression in a subset of RA patients. Our findings support the view that anti-TNF treatment is mainly symptomatic.

FoxP3 mRNA splice forms in synovial CD4+ T cells in rheumatoid arthritis and psoriatic arthritis

Our aim was to elucidate the relative amount of the different splice forms of FoxP3 mRNA in CD4+ T cells in peripheral blood (PB) compared to synovial fluid (SF) in RA and PsA patients. FoxP3 mRNA was measured using a quantitative real-time PCR method. CD4+ T cells were isolated from 17 paired samples of PB and SF from RA and PsA patients, and PB from 10 controls. FoxP3fl and FoxP3Δ2 mRNA was significantly increased (6.7 and 2.1-fold, respectively) in PB CD4+ T cells from RA patients compared to controls. FoxP3fl and Δ2 mRNA in SF CD4+ T cells was increased compared to controls in sero-negative RA and PsA, but not in sero-positive RA patients, who had a high FoxP3 expression in both PB and SF. The FoxP3Δ2Δ7 mRNA was barely detectable in patient samples, and not at all in healthy individuals. We provide evidence of an increased expression of FoxP3 splice forms in synovial CD4+ T cells from RA patients. A skewed, high expression profile of FoxP3, but not CTLA-4, in sero-negative RA and PsA, indicates that synovial CD4+ T cells may represent unique subsets of T cells which have been induced locally or selectively recruited to the joint.

A microdialysis study of topically applied diclofenac to healthy humans: Passive versus iontophoretic delivery

Topical application of NSAIDs is an alternative route to systemic administration when a local anti-inflammatory effect of the underlying tissue is a treatment option. The aim of the present microdialysis study was to assess and compare plasma and tissue levels of diclofenac when topically applied with or without iontophoresis in healthy adults. Fourteen healthy adults (26±9.4 years) were randomized to diclofenac applied by iontophoresis, or by a gel, in a crossover design. Diclofenac concentrations were measured in plasma and in microdialysis perfusates from the underlying tissues. Iontophoretic application resulted in the highest plasma concentration of 3.4±0.5 ng/ml (SEM given) compared to 0.4 ng/ml (at the detection limit) with gel, whereas no differences were observed between tissue concentrations for the two application methods, both being very low, below or around the detection limit. Iontophoresis caused skin reactions in 25% of the participants. Iontophoresis of diclofenac as compared to traditional topical application was not superior in order to increase the NSAID concentration locally and appears to have a higher frequency of skin reactions.

Collagen structure in skin from fibromyalgia patients

The distribution and amount of collagen in skin from a non-tender-point area from fibromyalgia patients was assessed by quantitative analysis of amino acids and by electron and light microscopy. Skin biopsies were obtained from the front of the thigh of 27 females who fulfilled the American College of Rheumatology criteria of fibromyalgia and from eight control subjects who were matched for gender, age and physical activity. Amino acids were determined by high-performance liquid chromatography. Electron and light microscopic investigations were carried out to examine tissue structure. Among the collagen-related amino acids, the mean number of hydroxyproline residues per 1,000 residues was 52.5 and 63.4 in fibromyalgia patients and control subjects, respectively (p = 0.050); proline residues were 81.7 and 110.0 (p = 0.006); and hydroxylysine residues were 14.7 and 10.1 (p = 0.002). The total amount of skin protein in proportion to dry tissue weight was 83.4% and 72.6% in fibromyalgia and controls, respectively (p = 0.037). The overall microscopic picture was normal. The lamellar structure of the perineurium and a deficiency in collagen packing in the endoneurium was observed more frequently and to a larger extent in fibromyalgia patients than in controls. In conclusion, there are some differences between the amino acid composition of skin proteins in fibromyalgia patients compared with controls. The amount of collagen may be lower in skin from fibromyalgia patients, and collagen packing in the endoneurium may be less dense.

Collagen and muscle pathology in fibromyalgia patients

OBJECTIVE

To measure collagen concentration and search for muscle pathology in muscle non-tender-point areas from fibromyalgia (FM) patients.

METHODS

Muscle biopsies were obtained from m. vastus lateralis of 27 carefully selected, female fibromyalgia patients, and from eight age-matched female control subjects. Amino acids were determined by HPLC and electron microscopy was performed.

RESULTS

The FM patients had lower hydroxyproline and lower total concentration of the major amino acids of collagen than the controls. No significant difference was seen in the concentration of the major amino acids of myosin or of total protein. Electron microscopy showed no significant differences between FM patients and controls although atrophied muscle fibrils occurred in FM patients only, but frequencies were not significantly different.

CONCLUSION

Fibromyalgia patients had a significantly lower amount of intramuscular collagen. This may lower the threshold for muscle micro-injury and thereby result in non-specific signs of muscle pathology.

Evaluation of chronic venous disease in the lower limbs: comparison of five diagnostic methods

To compare the usefulness of five diagnostic methods in ensuring deep vein patency, and in demonstrating site(s) of incompetence, 39 patients with clinical signs of chronic venous disease of a leg were included in a study of deep, superficial and perforator veins using triplex ultrasound (TUS), ascending phlebography (AP), descending phlebography (DP), continuous wave Doppler (CWD) and ambulatory strain gauge plethysmography (ASGP). One patient withdrew from the study. It was not possible to use all five methods in all 38 cases, and the methods could only be used partly in some cases. TUS, which allows anatomical, morphological and functional evaluation of the venous system, was chosen as the reference method. There was poor agreement between TUS and AP, and no agreement between TUS and ASGP, in the diagnosis of venous occlusion. AP demonstrated reflux (abnormal valves) in 7 of 22 patients with competent veins at TUS, and missed reflux in 13 of 15 patients with incompetent veins. Similarly, CWD overdiagnosed reflux in 13 of 20 patients and missed the reflux in 3 of 14 patients. DP was only technically possible in 11 patients. ASGP diagnosed venous reflux in all patients with incompetent deep veins, but also indicated deep vein or perforator vein reflux in all but one patient with competent deep veins. The agreement between TUS and the other methods in evaluating reflux in the deep veins was not better than that expected to occur by chance, Cohen's kappa being less that 0.20. It is concluded that AP, CWD and ASGP are of little value in the work-up of patients with deep venous insufficiency.