Comparison of glomerular function tests in children with cancer

Evaluation of renal function should be performed as part of the follow-up during and after chemotherapy in pediatric cancer patients. The aim of this study was to compare an isotope clearance method [isotope glomerular filtration rate (iGFR)] with alternative methods to determine GFR in such patients. Isotope GFR [^99mTc-labeled diethylene triaminopentoacetic acid (DTPA) or ⁵¹Cr-labeled ethylenediaminetetra-acetate (EDTA)] was measured in 36 children (112 studies) and compared with simultaneously measured creatinine clearance (CrCl), serum creatinine (SCr), and cystatin C (CysC) concentrations, as well as the results of Schwartz, Counahan–Barratt, and Cockroft–Gault formulae, using general linear mixed models. Our results showed a significant association between iGFR and CysC concentrations (p < 0.001). No linear relationship was observed between CrCl and iGFR (p = 0.7). As expected, the results of height-based formulae (Counahan–Barratt and Schwartz) had significantly (p = 0.004) better correlation to iGFR than the results of a formula based on weight (Cockroft–Gault) (p = 0.19). Despite significant linear correlation, intraclass correlation coefficients showed poor agreement. Tests of similarity between iGFR estimates showed differences between average values of GFR. Therefore, determination of iGFR remains the method of choice in estimation of GFR in cancer patients. In our study population, assay of serum CysC was the most reliable alternative method to measure glomerular function.     

Introducing navigated transcranial magnetic stimulation as a refined brain mapping methodology

A major intrinsic limitation of transcranial magnetic stimulation (TMS) to map the human brain lies in the unclear relationship between the position of the stimulating coil on the scalp and the underlying stimulated cortex. The relationship between structure and function as the major feature constituting a brain mapping modality can therefore not be established. Recent advances in image processing allowed us to refine TMS by combining magnetic resonance imaging (MRI) modalities with TMS using a neuronavigation system to measure the position of the stimulating coil and map this position onto a MRI data set. This technique has several advantages over recent TMS mapping strategies. The position of the coil on the scalp can be held constant as verified by real time visual guidance. When evaluating higher cortical functions, the relationship between underlying cortical anatomy and the scalp stimulation site can be accurately assessed. Cortical motor output maps can be easily obtained for preoperative planning and decision making for mass lesions near rolandic cortex in patients. In conclusion, navigated TMS is a reliable alternative for localizing cortical functions and therefore may be a useful adjunct or in selected patients even a helpful alternative to other functional neuroimaging methods. Electronic Publication     

Tibiotalocalcaneal arthrodesis with a compressive retrograde intramedullary nail: a report of 34 consecutive patients

BACKGROUND: Tibiotalocalcaneal arthrodesis is a treatment modality for severe arthrosis and malalignment of the hindfoot. Complications, such as delayed union and nonunion, are well-known risks of the procedure. Arthrodesis can be done with a plate, screws, an external fixator, or an intramedullary nail. Compression with an intramedullary nail was the focus of this report. METHODS: Thirty-four consecutive patients (23 men and 11 women) with an average age range of 57 (range 25-77) years had tibiotalocalcaneal arthrodesis using retrograde intramedullary compression nail fixation. Mean followup was 24 (range 6 to 43) months. One patient died of an unrelated cause, but 30 (91%) of the remaining 33 patients answered the questionnaire. RESULTS: Bony consolidation was achieved in 26 (76%) patients, the mean time to fusion being 16 weeks. Five patients (15%) had complications and seven (20%) had repeat surgery. Of the 30 patients who responded to the questionnaire, three patients (10%) evaluated the overall result subjectively as being of no benefit and 27 (90%) as improved. The visual analog scale (VAS) score for preoperative pain was 66 at rest and 83 when walking, and the mean postoperative scores were 19 and 32, respectively (p<0.001). CONCLUSIONS: Tibiotalocalcaneal arthrodesis with a compressive retrograde intramedullary nail is an effective and safe procedure for patients with severe malalignment or arthrosis of the hindfoot. It is essentially a salvage procedure, and most patients benefit from it, but excellent results are rare.     

Repeated metal ion measurements in patients with high risk metal-on-metal hip replacement

Purpose

Conventional follow-up methods are not sufficient to identify adverse soft tissue reactions in patients with metal-on-metal hip replacements. The national guidelines regarding metal ion measurements are debatable. The aims of our study were to investigate (1) if there is a clinically significant change in whole blood (WB) cobalt (Co) or chrome (Cr) levels in repeated WB assessment in patients operated on with ASR hip replacements, and (2) what proportion of patients has WB Co or Cr level below the previously established safe upper limits (SUL) in the repeated WB metal ion assessment.

Methods

We identified all patients (n = 254) with unilateral ASR implants who had second blood sample taken eight to 16 months after the first.

Results

WB Co and Cr levels remained below SUL and within their initial values during a mean one-year measurement interval in the majority of patients with a high risk HR device. In contrast to this, 50 % of patients with THRs had metal ion levels exceeding the SUL in the first measurement. WB Co values significantly increased over the measurement interval in the THR group.

Conclusion

In patients with a high risk HR, repeated metal ion measurement did not provide useful information for clinical decision-making. In patients with a LD MoM THR repeated measurements revealed a large number of patients with metal ion levels exceeding SUL and might thus be clinically beneficial.     

Pathophysiology of overuse tendon injury

Overuse tendon injury is one of the most common injuries in sports.The etiology as well as the pathophysiological mechanisms leading to tendinopathy are of crucial medical importance.At the moment intrinsic and extrinsic factors are assumed as mechanisms of overuse tendon injury. Except for the acute, extrinsic trauma, the chronic overuse tendon injury is a multifactorial process. There are many other factors, such as local hypoxia, less of nutrition, impaired metabolism and local inflammatory that may also contribute to the development of tissue damage.The exact interaction of these factors cannot be explained entirely at the moment.Further studies will be necessary in order to get more information.     

Bone tissue concentrations of ciprofloxacin released from biodegradable screws implanted in rabbits skull

Previously, ciprofloxacin-releasing polylactide/polyglycolide 80/20 (SR-PLGA) screws have proven to be biocompatible with sufficient strength. However, there has been no information about the local concentrations of ciprofloxacin in bone tissue after their implantation. To measure bone concentrations of ciprofloxacin, two screws were implanted in each rabbit, one on either side of the sagittal suture (n = 28 rabbits). Follow-up periods were 2, 4, 8, 16, 24, 52 and 78 weeks. From each rabbit, bone blocks containing one screw were retrieved and used to measure drug concentration. Ciprofloxacin concentration at 2 weeks follow-up was 4.4 ± 4.2 μg/g, 14.1 ± 2.7 μg/g at 4 weeks and 7.6 ± 4.5 μg/g at 8 weeks. Measured concentrations were very low at 16 weeks (mean 0.09 ± 0.04 μg/g) and 24 weeks (mean 0.04 ± 0.02 μg/g). Surprisingly, the concentration was higher again at 1 year (mean 1.3 ± 1.0 μg/g). At 1.5 years, concentration had decreased again (mean 0.8 ± 0.6 μg/g). The drug concentration in bone tissue was higher than minimal inhibitory concentration of ciprofloxacin (Staphylococcus aureus 0.1–1.0 μg/g) at 2, 4, and 8 weeks. Ciprofloxacin-releasing SR-PLGA 80/20 screws could be used clinically for osteofixation and infection treatment in cranial bone.     

Bioabsorbable miniplating versus metallic fixation for metacarpal fractures

Bioabsorbable implants offer an attractive alternative to metallic implants to stabilize small bone fractures in the hand. Self-reinforced bioabsorbable miniplating for metacarpal fractures was studied in bones from cadavers and compared with standard metallic fixation methods. One hundred twelve fresh-frozen metacarpals from humans had three-point bending and torsional loading after transverse osteotomy followed by fixation using seven methods: (1) dorsal and (2) dorsolateral 2-mm self-reinforced polylactide-polyglycolide 80/20 plating, (3) dorsal and (4) dorsolateral 2-mm self-reinforced poly-L/DL-lactide 70/30 plating, (5) dorsal 1.7-mm titanium plating, (6) dorsal 2.3-mm titanium plating, and (7) crossed 1.25-mm Kirschner wires. In apex dorsal and palmar bending, dorsal self-reinforced polylactide-polyglycolide and poly-L/DL-lactide plates provided stability comparable with dorsal titanium 1.7-mm plating. When the bioabsorbable plates were applied dorsolaterally, apex palmar rigidity was increased and apex dorsal rigidity was decreased. Bioabsorbable platings resulted in higher torsional rigidity than 1.7-mm titanium plating and in failure torque comparable with 2.3-mm titanium plating. Low-profile selfreinforced polylactide-polyglycolide and poly-L/DL-lactide miniplates provide satisfactory biomechanical stability for metacarpal fixation. These findings suggest that bioabsorbable miniplating can be used safely in the clinical stabilization of metacarpal and phalangeal fractures.     

Metalloproteinase inhibition reduces lung injury and improves survival after cecal ligation and puncture in rats

BACKGROUND: Neutrophil activation with concomitant matrix metalloproteinase-2 (MMP-2) and matrix metalloproteinase-9 (MMP-9) release has been implicated in the development of sepsis-induced acute lung injury. We hypothesized that COL-3, a chemically modified tetracycline known to inhibit MMP-2 and MMP-9, would reduce lung injury and improve survival in rats following cecal ligation and puncture (CLP). METHODS: Sprague-Dawley rats were separated into five groups: 1) sham CLP+ carboxymethylcellulose (CMC; vehicle for COL-3, n = 6); 2) sham CLP + COL-3 (n = 6); 3) CLP + CMC (n = 10); 4) CLP + single-dose (SD) COL-3 administered concomitant with CLP (n = 9); and 5) CLP + multiple-dose (MD) COL-3 administered concomitant with CLP and at 24 h after CLP (n = 15). Rats were sacrificed at 168 h (7 days) or immediately after death, with survival defined as hours after CLP. Histological lung assessment was made based on neutrophil infiltration, alveolar wall thickening, and intraalveolar edema fluid. Lung MMP-2 and MMP-9 levels were assessed by immunohistochemistry. MMP-2 and MMP-9 levels were correlated with survival by simple regression analysis. RESULTS: The mortality of rats in the cecal ligation and puncture without treatment group (CLP + CMC) was 70% at 168 h. A single dose of COL-3 in the CLP + COL-3 (SD) group significantly reduced mortality to 54%. Furthermore, with a repeat dose of COL-3 at 24 h after CLP, mortality was significantly reduced to 33%. Pathologic lung changes seen histologically in the CLP + CMC group were significantly reduced by COL-3. A significant reduction in lung tissue levels of MMP-2 and MMP-9 was noted in both groups treated with COL-3. Reduction of MMP-2 and MMP-9 levels correlated with improved survival. CONCLUSION: Inhibition of MMP-2 and MMP-9 by COL-3 in a clinically relevant model of sepsis-induced acute lung injury reduces pulmonary injury and improves survival in a dose-dependent fashion. Our results suggest that prophylactic treatment with COL-3 in high-risk patients may reduce the morbidity and mortality associated with sepsis-induced acute respiratory distress syndrome.