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Abstract Background In the current discussion of surgical treatment of arthroses in the ankle joint, arthrodesis is in competition with artificial joint replacement. Up until now, no valid biomechanical findings have existed on the changes in intraarticular loads following arthrodesis. One argument against tibiotalar arthrodesis is the frequently associated, long-term degeneration of the talonavicular joint, which can be attributed to changes in biomechanical stresses. Methods We used a dynamic model to determine the changes in intraarticular forces and peak-pressure in the talonavicular joint and in the calcaneocuboid joint on 8 cadaver feet under stress in a simulated stance phase following tibiotalar arthrodesis. Results The change seen after arthrodesis was a tendency of relocation of average force and maximum pressure from the lateral onto the medial column of the foot. The average force increased from native 92 N to 100 N upon arthrodesis in the talonavicular joint and decreased in the calcaneocuboid joint from 54 N to 48 N. The peak pressure increased from native 3.9 MPa to 4.4 MPa in the talonavicular joint and in the calcaneocuboid joint from 3.3 MPa to 3.4 MPa. The increase of force and peak pressure on the talonavicular joint and decrease of force on the calcaneocuboid joint is statistically significant. Conclusion The increase in imparted force and peak pressure on the medial column of the foot following tibiotalar arthrodesis, as was demonstrated in a dynamic model, biomechanically explains the clinically observed phenomenon of cartilage degeneration on the medial dorsum of the foot in the long term. As a clinical conclusion from the measurements, it would be desirable to reduce the force imparted on the medial column with displacement onto the lateral forefoot, say by suitable shoe adjustment, in order to achieve a more favourable long-term clinical result.

Multi-slice computed tomography (MSCT) is a non-invasive modality to visualize coronary arteries with an overall good image quality. Improved spatial and temporal resolution of 64-slice and dual-source computed tomography (DSCT) scanners are supposed to have a positive impact on diagnostic accuracy and image quality. However, quantitative parameters to compare image quality of 16-slice, 64-slice MSCT and DSCT are missing. A total of 256 CT examinations were evaluated (Siemens, Sensation 16: n = 90; Siemens Sensation 64: n = 91; Siemens Definition: n = 75). Mean Hounsfield units (HU) were measured in the cavum of the left ventricle (LV), the ascending aorta (Ao), the left ventricular myocardium (My) and the proximal part of the left main (LM), the left anterior descending artery (LAD), the right coronary artery (RCA) and the circumflex artery (CX). Moreover, the ratio of intraluminal attenuation (HU) to myocardial attenuation was assessed for all coronary arteries. Clinical data [body mass index (BMI), gender, heart rate] were accessible for all patients. Mean attenuation (CA) of the coronary arteries was significantly higher for DSCT in comparison to 64- and 16-slice MSCT within the RCA [347 +/- 13 vs. 254 +/- 14 (64-MSCT) vs. 233 +/- 11 (16-MSCT) HU], LM (362 +/- 11/275 +/- 12/262 +/- 9), LAD (332 +/- 17/248 +/- 19/219 +/- 14) and LCX (310 +/- 12/210 +/- 13/221 +/- 10, all p < 0.05), whereas there was no significant difference between DSCT and 64-MSCT for the LV, the Ao and My. Heart rate had a significant impact on CA ratio in 16-slice and 64-slice CT only (p < 0.05). BMI had no impact on the CA ratio in DSCT only (p < 0.001). Improved spatial and temporal resolution of dual-source CT is associated with better opacification of the coronary arteries and a better contrast with the myocardium, which is independent of heart rate. In comparison to MSCT, opacification of the coronary arteries at DSCT is not affected by BMI. The main advantage of DSCT lies with the heart rate independency, which might have a positive impact on the diagnostic accuracy. [ABSTRACT FROM AUTHOR]

In preterm infants receiving supplemental oxygen, manual control of the inspired oxygen fraction is often time-consuming and inappropriate. We developed a system for automatic oxygen control and hypothesized that this system is more effective than routine manual oxygen control in maintaining target arterial oxygen saturation levels. We performed a randomized controlled crossover clinical trial in 12 preterm infants receiving nasal continuous positive airway pressure and supplemental oxygen. Periods with automatic and routine manual oxygen control were compared with periods of optimal control by a fully dedicated person. The median (range) percentage of time with arterial oxygen saturation levels within target range (87-96%) was 81.7% (39.0-99.8) for routine manual oxygen control, 91.0% (41.4-99.3) for optimal control, and 90.5% (59.0-99.4) for automatic control (ANOVA: p = 0.01). Pairwise post hoc comparisons revealed a statistically significant difference between automatic and routine manual oxygen control (Dunnett's test: p = 0.02). The frequency of manual oxygen adjustments was lowest in automatic control (Friedman's test: p < 0.001). Automatic oxygen control may optimize oxygen administration to preterm infants receiving nasal continuous positive airway pressure and reduce nursing time spent with oxygen control. [ABSTRACT FROM AUTHOR]

The aim of this study was to investigate the relationship between proliferative capacity, represented by the immunohistochemical labeling index of the proliferation marker MIBl, and treatment failure in a matched-pair study design of recurrent and non-recurrent carcinoma initially treated with primary surgery combined with curative post-operative radiation. The study concludes that a high MIBl labeling index is an indicator for treatment failure in these patients. The data show that for squamous cell carcinoma of the oropharynx and oral cavity the detection of Ki-67 is an unfavorable prognostic factor.

Background: Bioelectrical impedance analysis (BIA) is a popular technique which can be used to track longitudinal changes in body composition. However, precision of the technique has been questioned, especially among athletic populations where small but meaningful changes are often observed. Guidelines exist which attempt to optimize precision of the technique but fail to account for potentially important variables. Standardization of dietary intake and physical activity in the 24 hr prior to assessment has been proposed as an approach to minimizing the error of impedance-derived estimates of body composition., Methods: Eighteen recreational athletes, male (n = 10) and female (n = 8), underwent two consecutive BIA tests to quantify within-day error, and a third test (the day before or after) to quantify between-day error. All food and fluid intake plus physical activity from the 24 hr prior to the first BIA scan was replicated during the following 24 hr. Precision error was calculated as the root mean square standard deviation, percentage coefficient of variation, and least significant change., Results: There were no significant differences in precision error of within- and between-day fat-free mass, fat mass, and total body water. Differences in precision error of fat-free mass and total body water, but not fat mass, were less than the smallest effect size of interest., Conclusion: The 24-hr standardization of dietary intake and physical activity may be an effective approach to minimizing precision error associated with BIA. However, further research to confirm the validity of this protocol compared to nonstandardized or randomized intake is warranted.

Aim: 3D digital surface photogrammetry is an objective means of documenting the quantitative evaluation of facial morphology. However, there are no standardized superimposition and measurement systems for surveying soft tissue changes. The aim of this study was to present a superimposition and measurement model for three-dimensional analysis of therapy-induced sagittal changes in facial soft tissue and to ascertain its applicability based on the reproducibility of 3D landmark positions., Patients and Method: Twenty-nine children were examined (eight with cleft lip and palate, six with cleft palate, eight with Class III malocclusion and seven healthy controls, between 4.1 and 6.4 years). The mean time between examinations was 8.2 months for the patients and 8 months for the control group. Data was acquired with the DSP 400((c))imaging system. A mathematical model with seven superimposition points was developed. Two 3D images, one at the beginning and the other at the end of the examination, were generated. Both images were superimposed ten times. Ten landmarks for evaluating the soft tissue changes were geometrically defined on the superimposition image, put in place ten times, and measured. The landmarks' reproducibility was calculated via statistical intraoperator analysis. Measurement error was identified using the root mean square error (RMSE)., Results: The superimposition points were easy to locate and the landmarks well definable. All midface landmarks proved to be highly reproducible with an RMSE under 0.50 mm. The lower face landmarks demonstrated good reproducibility with an RMSE under 1 mm. The midface landmarks' precision fell below the range of accuracy, while the lower face landmarks' precision fell within the optoelectronic scanner device's range of accuracy (0.50-1 mm)., Conclusions: As an accurate, non-invasive, millisecond-fast, non-ionizing and ad infinitum repeatable procedure, 3D digital surface photogrammetry is very well suited for clinical and scientific application in orthodontics. We developed a reliable superimposition and measurement model with 3D digital surface photogrammetry. This new capturing and measurement system provides a simple means of determining 3D changes in facial soft tissue. Our landmarks proved to be highly reproducible for the midface while revealing good reproducibility for the lower face.

Aim: Rapid Maxillary Expansion (RME) and Delaire facemask are a well-established treatment method for patients with cleft lip and palate and Class III malocclusion. Several roentgenocephalometric studies on skeletal effects of this therapy are known. However, there are no systematic studies on soft tissue changes. The aim of this study was to analyze three-dimensionally the soft tissue changes in facial morphology of children with cleft lip and palate and Class III malocclusion under therapy with RME and Delaire facemask., Patients and Method: A prospective longitudinal clinical trial was undertaken. 29 children between 4.1 and 6.4 years were divided into four groups: eight patients with unilateral cleft lip and palate (group 1), six patients with isolated cleft palate (group 2), eight patients with Class III malocclusion (group 3). The mean treatment period with RME and Delaire mask was 8.2 months. Seven untreated children with no need of orthodontic treatment were chosen as the control (group 4). Two 3D images, one at the beginning and one at the end of the study, were generated with the DSP 400((c)) imaging system. Both images were superimposed ten times and measured ten times., Results: We detected significant forward rotation and forward displacement of the soft tissue in the lower midface with the dentoalveolar areas in all patient groups. No significant asymmetric forward displacement of the soft tissue in the maxilla could be verified in the lower or upper midface, not even in the unilateral cleft lip and palate patients. Among the groups, the Class III malocclusion patients showed greater maxillary soft tissue changes., Conclusion: The RME and the Delaire facemask demonstrated the greatest effectiveness in the lower midface soft tissue in terms of forward displacement and forward rotation in the cleft lip and palate patients, particularly in the Class III patients. The 3D data allowed us to discriminatively interpret the effects of the orthopedic mask on the entire maxillary complex and maxillary alveolar process. In the unilateral cleft lip and palate patients, there was descriptively both symmetric and asymmetric advancement of the midface soft tissue.

Study Design: Study to determine the internal consistency and validity of adapted German version of Scoliosis Research Society-22 (SRS-22) questionnaire., Objective: To evaluate the validity and reliability of adapted German version of SRS-22 questionnaire., Summary of Background Data: The SRS-22 questionnaire was developed to assess the health-related quality of life for English-speaking patients with idiopathic scoliosis. For scientific purpose and standardized comparison of outcome studies for the treatment of idiopathic scoliosis its adaptation into German is necessary to respect cultural and lingual differences., Methods: Translation/retranslation of the English version of the SRS-22 was conducted, and all steps for cross-cultural adaptation process were performed. Thus, SRS-22 questionnaire and previously validated Roland-Morris score were mailed to 222 patients who had been treated surgically or conservatively for idiopathic scoliosis. Seventy-eight patients (35%) responded to the first set of questionnaires and 54 of the first time responder returned their second survey. The median age of all patients who joined the study was 19 years. Measures of reliability namely, selectivity, internal consistency, and reproducibility were determined by Cronbach's alpha statistics and intraclass correlation coefficient, respectively. Concurrent validity was measured by comparing with an already validated questionnaire (Roland-Morris score). Measurement was made using the Spearman correlation coefficient., Results: The study demonstrated satisfactory internal consistency with high Cronbach's alpha values for 4 of the corresponding domains (pain, 0.75; self-image, 0.84; mental health, 0.88; and satisfaction, 0.61). However, the Cronbach's alpha value for function/activity domain (0.67) was considerably lower than the original English questionnaire. For the same domains intraclass correlation coefficient demonstrating satisfactory test/retest reproducibility., Conclusion: The adapted German version of the SRS-22 questionnaire can be used to assess the outcome of treatment for German-speaking patients with idiopathic scoliosis.

Purpose: To determine with comparison of two different monopolar radiofrequency (RF) devices whether a longer duration of energy application has an effect on coagulation necrosis in ex vivo bovine liver tissue., Materials and Methods: The volume and short- and long-axis diameters of the coagulation were assessed in ex vivo bovine livers after RF application for 5-60 minutes. A power of 60 W was used for the single perfusion applicator (n = 48), and a power of 200 W was used for the internally cooled cluster applicator (n = 48). Reproducibility and coagulation shape were assessed and compared. For statistical evaluation, the mean values of the dimensions were compared by using analysis of variance with the following factors: applicator, RF duration, and their interaction., Results: RF application up to 60 minutes produced a mean maximum volume of coagulation of 116.8 cm(3)(95% confidence interval [CI]: 98.4 cm(3), 138.8 cm(3)) for the single perfusion device and 89.5 cm(3)(95% CI: 75.4 cm(3), 106.3 cm(3)) for the internally cooled cluster applicator. For both devices, duration of energy application up to 60 minutes showed a significant interaction for the volume and the short- and long-axis diameters of coagulation (P < .0001). The volumes of coagulation necrosis induced with the internally cooled cluster applicator were more reproducible than those induced with the single perfusion applicator (P < .0001). The shape of the lesion was closer to a sphere (mean shape ratio, 0.98) for the internally cooled cluster than for the single perfusion applicator (mean shape ratio, 1.21) (P < .0001)., Conclusions: There is a significant interaction between RF duration and both RF devices influencing the dimensions of coagulation. Longer durations of energy application expand the volume of coagulation with a better reproducibility and more spherical shape of coagulation for the internally cooled cluster device.

Background: To determine the accuracy of contrast-enhanced multislice computed tomography (CT) in the assessment of treatment success immediately after CT-guided radiofrequency (RF) ablation., Methods: 26 patients with 38 Colorectal liver metastasis (CRM) were treated by CT-guided RF ablation. Pre-contrast and portal phase CT features before and immediately after ablation were retrospectively evaluated quantitatively and qualitatively: Influence of attenuation characteristics, safety margin, congruency between tumor and coagulation, and morphological criteria (shape, margin distinction, margin configuration, and margin continuity) were investigated. Findings were statistically analyzed with regard to local tumor progression., Results: Mean observation period for follow-up scans was 6.4 months (range: 3-40 months). Attenuation characteristics, safety margin, and congruency had no significant effect on the probability of local tumor progression. Coagulations whose margin was categorized as "discontinuous" were significantly more often associated with local recurrence (p = 0.038). No significant influence on local recurrence could be detected regarding coagulation shape, margin distinction, and configuration., Conclusion: Computed tomography imaging immediately after RF ablation allows for morphological characterization of the coagulation and provides a valid baseline status for follow-up imaging. However, in CRM, morphological image criteria and attenuation characteristics have limited predictive value for immediate detection of persistent tumor.

Background: Proteins of the Bcl-2 family prevent cells of various tumor types from undergoing apoptosis and thus contribute to their chemotherapy resistance. The phenotype of multidrug resistance is a major factor for poor treatment results of advanced epithelial liver tumors in children. The role of Bcl-2 proteins in these tumors is yet unclear. The purpose of this study was to analyze the influence of Bcl-2 on the chemotherapy resistance of hepatoblastoma (HB) and pediatric hepatocellular carcinoma (HCC)., Materials and Methods: Bcl-2 expression was analyzed in the HB cell lines HUH6 and HepT1 as well as in the HCC cell line HepG2 before and after treatment with cisplatin, doxorubicin, taxol, and etoposid. Silencing of the Bcl-2 gene was performed via RNA interference using specific siRNA. Treatment efficiencies of cytotoxic agents were assessed against original and Bcl-2 siRNA transfected tumor cells., Results: The mixed HB cell line HUH6 showed a relevant amount of Bcl-2 expression, which increased after chemotherapy. In these cells Bcl-2 appeared within the nuclei and the cytosol. Treatment with all cytotoxic agents was significantly improved through Bcl-2 siRNA (P < 0.001-0.0054) in this cell line. There was no effect of Bcl-2 siRNA in HepT1 and HepG2 cells., Conclusions: Bcl-2 seems to play a role in antiapoptotic mechanisms of some HB subtypes. Thus, this gene might serve as target for a gene-directed adjuvant therapy. Further studies seem necessary to clear the susceptibility of pediatric epithelial liver tumors toward the described approach.

Aim: Little has been known until now about biomechanical intra-articular changes in the condition of adjacent joints following subtalar arthrodeses., Method: We tested 5 cadaver specimens in a dynamic axially loaded foot model under computer-regulated load application on 9 extrinsic tendons of the foot regarding changes in load under native conditions and following an anatomically fixed subtalar arthrodesis., Results: We saw an averaged native force transmission in the talonavicular joint of 87 N, increasing post-arthrodesis to 92 N. In the calcaneocuboid joint we measured an increase from 72 N to 74 N. For peak pressure, the increase was from native 3152 kPa to 3286 kPa in the talonavicular joint and in the calcaneocuboid joint we recorded a reduction from 3282 kPa to 3277 kPa. The effects are not striking from a statistical viewpoint. However, we observed a reduction in force from native 103 N to 90 N and in peak pressure from 4778 kPa to 4261 kPa in the ankle. When the ankle was divided into discrete zones in the sagittal and frontal planes there was no evidence of load displacement., Conclusion: Our measurements show that anatomically fixed arthrodeses of the talocalcanear joint do not lead to any striking increase in loads on adjacent joints. Any adjacent segment degeneration following subtalar arthrodeses may be the result of changes in joint kinematics or non-anatomically reconstructed hindfoot positions.

Background: Talonavicular arthrodesis is a differential indication for triple arthrodesis. Differences regarding intraarticular pressure loads on the adjacent joints have not been investigated to date, but they are of clinical relevance when considering long-term joint degeneration., Methods: We used a dynamic foot model to measure intraarticular peak pressures with electronic sensors in 8 anatomical specimens in different areas of the ankle joint and in the naviculocuneiform joint. Force was applied to extrinsic tendons via cables attached to computer- regulated hydraulic cylinders. A ground reaction force was simulated in a tilting angle- and force-controlled translation stage., Results: We measured significantly higher peak pressures in the ankle joint after triple arthrodesis (5.7 Mpa) than after talonavicular arthrodesis (5.2 Mpa), with differences especially in the anterior section (5.2 Mpa as compared to 4.6 Mpa). Centrally, the peak pressure was similar, at 4.6 MPa and 4.5 Mpa, respectively. In the posterior area, the peak pressure after triple arthrodesis was lower (4.1 MPa as opposed to 4.4 Mpa). After triple arthrodeses, we measured higher values laterally/medially in the ankle joint (5.5 MPa/4.6 Mpa) than after talonavicular arthrodesis (5.1 MPa/4.4 Mpa). In the naviculocuneiform joint, we again saw higher peak pressures after triple arthrodesis than after talonavicular arthrodesis., Interpretation: Our findings from this cadaver study indicate a lower and more evenly distributed peak pressure load in the ankle joint after talonavicular arthrodesis than after triple arthrodesis; thus, mechanically, a selective arthrodesis appears to be more favorable. In contrast, triple arthrodesis leads to an increase in peak pressure in the ankle joint, which may in turn lead to joint degeneration.

Objective: To test the hypothesis that a new orthodontic appliance with a velar extension that shifts the tongue anteriorly would reduce upper airway obstruction in infants with Pierre Robin sequence (PRS)., Study Design: Eleven infants with PRS (median age, 3 days) and an apnea index (AI) >3 were studied. The effect of the new appliance on the AI was compared with that of a conventional appliance without a velar extension by using a crossover study design with random allocation., Results: Compared with baseline (mean AI, 13.8), there was a significant decrease in the AI with the new appliance (3.9; P value <.001), but no change with the conventional appliance (14.8; P = .842). Thus, the relative change in AI was -71% (95% CI, -84--49) for the new appliance and +8% (95% CI, -52-142) for the conventional appliance, which was significantly different (P = .004). No severe adverse effects were observed., Conclusion: This new orthodontic appliance appears to be safe and effective in reducing upper airway obstruction in infants with PRS.

Objectives: We investigated the influence of magnetic resonance (MR) at 3.0 T on clonogenic ability, proliferation, and cell cycle in an embryonic human cell line., Materials and Methods: Cells (human lung fibroblasts Hel 299) were exposed to the static magnetic field (3.0 T) of a magnetic resonance imager (MRI) and to a turbo spin echo sequence at 3.0 T within clinical limitations (specific absorption rate 0.92 W/kg). A special MR-compatible incubation system was used. A control group (sham-exposed) and a MRI group (exposed) were set up. We investigated 3 biologic endpoints: colony forming, cell cycle, and proliferation ability. The exposure time was 2 hours in each experiment., Results: In the statistical analysis, none of these tests showed relevant differences between the exposed and sham-exposed group., Conclusions: No influences of the static field alone as well as a turbo spin echo sequence at 3.0 T on clonogenic ability, proliferation, or cell cycle in eugenic human lung fibroblasts were found.

Purpose: Evaluation of bipolar radiofrequency (RF) ablation using internally cooled electrodes in an ex-vivo experiment., Materials and Methods: Bipolar RF ablations (n = 154) were performed in ex-vivo bovine liver. Both electrodes with a total length of the active tip of 4 cm were located on the same shaft of an internally cooled applicator. The power output was systematically varied between 20 and 100 watts (W). The energy application was continuous or modulated depending on the tissue resistance. In relationship to the maximum power output, the volume of coagulation was assessed., Results: In continuous energy application the induced volume of coagulation was increased at lower power outputs up to 33.7 cm (3) (20 watts). Parallel to an increased volume of coagulation, the required duration of energy application was increased up to a maximum of 51.6 minutes. Modulation of the power output as a function of the tissue resistance enabled application of a wide range of power outputs (40 - 75 watts) leading to a comparable extent of coagulation with a maximum of 14.9 cm (3) (10 min.), 16.8 cm (3) (15 min.), and 19.1 cm (3) (20 min.)., Conclusion: Continuous application of RF energy leads to an inverse relationship between volume of coagulation and power output. Modulation of the power output as a function of the tissue resistance enables application of a wider range of power outputs compared to continuous application of RF energy.

Objectives: The aim of this study was to quantify image quality gains of a moving coronary plaque phantom using dual-source computed tomography (DSCT) providing 83 milliseconds temporal resolution in direct comparison to 64 slice single-source multidetector CT (MDCT) with a temporal resolution of 165 milliseconds., Materials and Methods: Three cardiac vessel phantoms with fixed 50% stenosis and changing plaque configurations were mounted on a moving device simulating cardiac motion. Scans were performed at a simulated heart frequency of 60 to 120 bpm. Image quality assessment was performed in different anatomic orientations inside a thoracic phantom., Results: A significant improvement of image quality using the DSCT could be found (P=0.0002). Relevant factors influencing image quality aside from frequency (P=0.0002) are plaque composition (P<0.0001), as well as orientation (P<0.0001)., Conclusion: Scanning with 83 milliseconds temporal resolution improved image quality of coronary plaque at higher heart frequencies.

Purpose: To prospectively determine if static magnetic fields of magnetic resonance (MR) imagers affect radiofrequency (RF) ablation coagulation volume and shape., Materials and Methods: Ex vivo RF ablations of bovine livers were performed with magnetic field strengths of 0.2, 1.5, and 3.0 T and were compared with ablations performed outside the magnetic field in a control group. Two MR-compatible monopolar RF devices (internally cooled single and cluster electrodes) were systematically tested. Length of long axis (y-axis), length of two short axes (x- and z-axes), and coagulation volume and shape measured outside and inside different magnetic fields were compared with the Dunnett test. Significance level was set to .05., Results: For the single electrode, no significant difference was observed between length of short axes and coagulation volume and shape measured inside and outside the magnetic field. Mean x- and z-axis lengths were 2.3 and 2.6 cm, respectively, outside the magnetic field; 2.4 and 2.4 cm, respectively, at 0.2 T; 2.5 and 2.6 cm, respectively, at 1.5 T; and 2.2 and 2.5 cm, respectively, at 3.0 T. Differences between length of long axis, length of short axis perpendicular to static magnetic field, and coagulation volume and shape achieved with the cluster electrode inside and outside the magnetic field were not significant. Mean x- and z-axis lengths were 3.9 and 3.9 cm, respectively, outside the magnetic field; 3.7 and 3.8 cm, respectively, at 0.2 T; 4.0 and 4.3 cm, respectively, at 1.5 T; and 3.8 and 3.8 cm, respectively, at 3.0 T. Differences between ablations performed at 1.5 T and those performed in the control group with the cluster electrode were significant (P = .026). In this case, a difference of 4 mm in the length of the short axis parallel to the magnetic field was detected, but there was no significant difference in coagulation volume., Conclusion: No significant differences in coagulation volume and shape could be recorded between RF ablations performed outside and those performed inside the static magnetic field., ((c) RSNA, 2006.)

Tumors of the choroid plexus (CPTs) are rare neoplasms of neuroectodermal origin usually arising in pediatric patients. However, CPT may occur at any age, and their distinction from metastatic carcinomas is often difficult in adult cases. Because CPTs frequently show focal glial differentiation, we now investigated 35 CPTs (19 males and 16 females 0.3-70 years old; median age, 25.0 years), including 21 choroid plexus papillomas (CPPs), 5 atypical CPP, and 9 choroid plexus carcinomas regarding their expression of the excitatory amino acid transporter-1 (EAAT1, corresponding to rodent GLAST/GLAST-1) by immunohistochemistry. In addition, 77 metastatic carcinomas, including 64 adenocarcinomas with mostly papillary formations, derived from different organs were examined. Of the 35 CPTs, 23 (66%) showed membranous EAAT1 expression in variable numbers of tumor cells, including all atypical CPP and 3 of 9 choroid plexus carcinomas (33%). None of the metastatic carcinomas showed membranous immunostaining. Excitatory amino acid transporter-1 expression in CPT was significantly age dependent (P < .0001), with the proportion of EAAT1-positive tumor cells increasing with age, but not sex dependent. There was a highly significant difference between EAAT1 expression in CPT and in metastatic carcinomas (P < .0001). Establishing a cutoff value of 1% immunoreactive tumor cells served in adult cases to distinguish CPT from metastatic adenocarcinomas with 100% specificity and 70% sensitivity and was associated with positive and negative predictive values of 100% and 91%, respectively. Our findings indicate that EAAT1 immunohistochemistry may be useful in differentiating CPT from metastatic carcinomas.

Conjugates of human lysozyme and horseradish peroxidase (HRP) were prepared by means of the heterobifunctional reagent N-succinimidyl 3-(2-pyridyldithio) propionate. A conjugate containing 2 mol HRP/mol lysozyme was isolated by gel filtration and used as a labeled antigen in competitive enzyme immunoassays, in which anti-lysozyme rabbit IgG had been bound to wells of microtiter plates. The assay can detect as little as 1 microgram lysozyme/l. The following reference intervals have been established: 950-2450 micrograms/l for serum, 1.7-123 micrograms/l for urine, 17.6-118 micrograms/l for cerebrospinal fluid and 0.04-1.5 microgram/g for feces.