Leonhard Gruber

Delineation of the Key Aspects in the Regulation of Epithelial Monolayer Formation

ABSTRACT The formation, maintenance, and repair of epithelial barriers are of critical importance for whole-body homeostasis. However, the molecular events involved in epithelial tissue maturation are not fully established. To this end, we investigated the molecular processes involved in renal epithelial proximal-tubule monolayer maturation utilizing transcriptomic, metabolomic, and functional parameters. We uncovered profound dynamic alterations in transcriptional regulation, energy metabolism, and nutrient utilization over the maturation process. Proliferating cells exhibited high glycolytic rates and high transcript levels for fatty acid synthesis genes (FASN), whereas matured cells had low glycolytic rates, increased oxidative capacity, and preferentially expressed genes for beta oxidation. There were dynamic alterations in the expression and localization of several adherens (CDH1, -4, and -16) and tight junction (TJP3 and CLDN2 and -10) proteins. Genes involved in differentiated proximal-tubule function, cilium biogenesis (BBS1), and transport (ATP1A1 and ATP1B1) exhibited increased expression during epithelial maturation. Using TransAM transcription factor activity assays, we could demonstrate that p53 and FOXO1 were highly active in matured cells, whereas HIF1A and c-MYC were highly active in proliferating cells. The data presented here will be invaluable in the further delineation of the complex dynamic cellular processes involved in epithelial cell regulation.

Uromodulin facilitates neutrophil migration across renal epithelial monolayers

The glycosylated protein uromodulin is exclusively found in the thick ascending limb cells (TAL) of the kidney, where it is produced on mass and apically targeted, eventually being secreted into the urine. Recently, there has been a renewed interest in this protein due to its ability to interact with the immune system, implicating this protein as a renal inflammatory molecule. Here we investigated the potential role of membrane bound uromodulin on neutrophil adhesion and trans-epithelial migration. The renal tubular epithelial cell line, LLC-PK1, stably transfected with human uromodulin was used to investigate the influence of uromodulin on neutrophil adherence and migration. Uromodulin expression resulted in a significant increase of neutrophil adherence and trans-epithelial migration, in both the apical to basolateral and the basolateral to apical direction. Although uromodulin is GPI anchored and targeted to the apical membrane, we could also observe expression in the basal and lateral membranes domains, which may be responsible for basolateral to apical migration. Furthermore we show that uromodulin binds both the heavy and light chain of IgG, and that IgG enhances neutrophil migration. This study demonstrates that uromodulin can facilitate neutrophil trans-epithelial migration and that this migration can be amplified by co-factors such as IgG.

Value of Multiparametric US in the Assessment of Intratesticular Lesions

Purpose To evaluate the diagnostic accuracy of multiparametric ultrasonography (US) consisting of gray-scale US, color Doppler US, strain elastography, and contrast agent-enhanced US in the assessment of intratesticular lesions. Materials and Methods Institutional review board approval was obtained for this retrospective study. From January 2012 to December 2015, 55 focal testicular lesions that were indeterminate on gray-scale US scans were further characterized with color Doppler US, strain elastography, and contrast-enhanced US. Strain elastography was performed to assess tissue elasticity, and hard lesions were defined as malignant. Color Doppler US and contrast-enhanced US were performed to determine the absence or presence of vascularization. Avascular lesions were defined as benign. Histopathologic results or follow-up examinations served as reference standards. Correct classification rate, sensitivity, specificity, and likelihood ratio were calculated. Results Of 55 testicular lesions, 43 (78.2%) were benign and 12 (21.8%) were malignant. Single-modality sensitivities and specificities were 66.7% and 88.4% for color Doppler US, 100% and 76.7% for contrast-enhanced US, and 100% and 72.1% for strain elastography, respectively. Among 12 malignant lesions, color Doppler US failed to demonstrate vascularization in four (33.3%) lesions, which were positive for cancer at contrast-enhanced US. By combining strain elastography and contrast-enhanced US, a sensitivity of 100% and specificity of 93.0% were achieved in differentiating benign and malignant focal testicular lesions. Positive likelihood ratio was 5.7 for color Doppler US, 4.3 for contrast-enhanced US, 3.6 for strain elastography, 14.3 for strain elastography combined with color Doppler US, and 14.3 for strain elastography combined with contrast-enhanced US. Conclusion Multiparametric US allows for a reliable differentiation of benign and malignant intratesticular lesions and can potentially be useful in deciding whether orchiectomy can be replaced with follow-up or less invasive organ-sparing strategies.

Focused high-resolution sonography of the suprascapular nerve: A simple surrogate marker for neuralgic amyotrophy?

OBJECTIVES To define the diagnostic value of high-resolution ultrasound (HRUS) of the suprascapular nerve (SSN) in the diagnosis of neuralgic amyotrophy (NA). METHODS The cross-section areas (CSA) of the SSN at the C5 root (CSA1) and the omohyoid muscle in the midclavicular line (CSA2) were assessed bilaterally in 15 healthy volunteers and 14 patients with clinically and electrophysiologically verified NA. Receiver-operator-characteristics (ROC) curves were generated and cut-off values, sensitivity, specificity, positive (PPV) and negative predictive values (NPV), likelihood (LR) and odds ratios (OR) were calculated. RESULTS Patients with NA had significantly higher CSA2-values than controls (6.36±2.75vs. 2.79±0.83mm2, p<0.0001) and significantly higher ratios of SSN CSA2-values of the affected vs. contralateral side (224.6±78.5% vs. 127.7±51.1%, p<0.0001). The ratios of SSN CSA2-values vs. CSA1-values (146.7±74.5% vs. 99.9±28.3%, p=0.008) and CSA1-values were also significantly higher (4.70±2.00vs. 2.90±0.90mm2, p=0.0028) than in controls. Beyond a CSA2 cut-off value of 4.2mm2, the ROC-AUC was 0.939 [0.861-1.00] when compared against healthy volunteers and 0.971 [0.901-1.00] when compared to patients with degenerative shoulder pain. Sensitivity was 85.7% [57.2-98.2%], specificity 96.7% [82.8-99.9%], PPV 92.3% [64.0-99.8%], NPV 93.5% [78.6-99.2%], OR 174.0 [14.4-2106.0] and LR 25.7 (95% confidence intervals in brackets). CONCLUSION SSN swelling in the lateral cervical region could be a supportive finding to identify NA patients. SIGNIFICANCE This method allows for the rapid sonographic identification of NA.

Sonoelastography of the Common Flexor Tendon of the Elbow with Histologic Agreement: A Cadaveric Study

Purpose To determine the correlation of the results of conventional B-mode ultrasonography (US) and compression sonoelastography with histologic results in common flexor tendons of the elbow in human cadavers. Materials and Methods Twenty-five common flexor tendons were evaluated in 16 fresh, unembalmed cadavers of 11 women with a median age of 85 years (range, 71-101 years) and five men with a median age of 78 years (range, 70-88 years). Informed consent was provided according to the last will of the donors. B-mode US results were classified as grade 1, normal tendon with homogeneous fibrillar pattern; grade 2, tendon thickening or hypoechoic areas and/or calcifications in less than 30% of the tendon; or grade 3, hypoechoic areas and/or calcifications greater than 30% of the tendon. Sonoelastographic results were grade 1, blue (hardest) to green (hard); grade 2, yellow (soft); and grade 3, red (softest). The intraclass correlation coefficient was calculated to determine agreement with histologic findings for each B-mode US, sonoelastographic, and combined B-mode US and sonoelastographic examination. Histologic results were grade 1, normal, with parallel fibrillar pattern; grade 2, mild tendinopathy, with cellular infiltration, angiogenesis, or fatty vacuoles; or grade 3, severe tendinopathy, with loss of parallel collagen structure and necrosis. Results Histologic alterations were detected in 44% (11 of 25) of biopsy specimens. Intraclass correlation with histologic results was 0.57 for B-mode US, 0.68 for sonoelastography, and 0.84 for the combination of the two approaches. Conclusion The addition of sonoelastography to B-mode US provided statistically significant improvement in correlation with histologic results compared with the use of B-mode US alone (P < .02).

Soft-Tissue Tumor Contrast Enhancement Patterns: Diagnostic Value and Comparison Between Ultrasound and MRI

OBJECTIVE The purpose of this study was to assess and compare contrast-enhanced ultrasound and MRI patterns in the diagnosis of soft-tissue masses. MATERIALS AND METHODS Two hundred fifty-five consecutively registered patients with histologically confirmed soft-tissue masses were included in this retrospective study. The diagnostic properties of four predefined contrast enhancement (CE) patterns were assessed, and logistic regression analysis was performed to determine the correlation between diagnosis and CE pattern, lesion size, and patient age and sex. The influence of lesion size on the occurrence of inhomogeneous CE patterns in malignancies was also determined. RESULTS Homogeneous CE patterns were highly specific for benignity, and inhomogeneous CE was moderately specific for malignancy in both ultrasound and MRI. A combination of homogeneous and inhomogeneous CE patterns led to 88.3% and 88.7% sensitivity, 66.7% and 59.7% specificity, 73.4% and 68.2% correct classification, 54.6% and 47.8% positive predictive value, 92.6% and 92.7% negative predictive value, 2.65 and 2.20 positive likelihood ratio, and 0.18 and 0.19 negative likelihood ratio for contrast-enhanced ultrasound and contrast-enhanced MRI. Cases with homogeneous CE in either ultrasound or MRI also were predominantly benign. The occurrence of inhomogeneous CE in malignant lesions increased with size. CONCLUSION CE patterns in ultrasound and MRI offer additional information about the differentiation of an unknown soft-tissue mass. The results of this study showed that homogeneous or absent CE was specific for benign differentiation and that heterogeneous CE was linked to malignancy. The routine analysis of CE patterns should increase diagnostic reliability in unclear soft-tissue masses.

Gender influence on clinical presentation and high-resolution ultrasound findings in primary carpal tunnel syndrome: do women only differ in incidence?

PurposeHigh-resolution ultrasound is increasingly used in the diagnosis of carpal tunnel syndrome; yet little is known about gender differences in clinical presentation and ultrasound findings.Materials and methodsIn this high-resolution ultrasound-based retrospective study in 170 cases, we assessed gender influence in CTS in terms of the severity of neural alterations by wrist-to-forearm ratio (WFR), epineural thickening, loss of fascicular anatomy, as well as classical signs and symptoms. The control group consisted of 42 wrists.ResultsWomen present with a greater WFR at first admission are affected more often bilaterally, and report less subjective pain intensity, while men report fewer nightly pain episodes at higher WFR. Loss of fascicular anatomy is three times more frequent in women. An increase in epineural thickness, loss of fascicular anatomy, and involvement of more than 1.5 fingers correlate significantly with WFR regardless of sex.ConclusionWomen differ significantly from men in terms of clinical presentation and ultrasound findings upon first diagnosis of CTS, which should be included in further diagnostic considerations.

Compared to 123I-MIBG SPECT/CT, 18F-DOPA PET/CT provides accurate tumor extent in patients with extra-adrenal paraganglioma

AimThe aim of this study was to compare the accuracy of 123I-MIBG SPECT/CT with that of 18F-DOPA PET/CT for staging extra-adrenal paragangliomas (PGLs) using both functional and anatomical images (i.e., combined cross-sectional imaging) as the reference standards.MethodsThree men and seven women (age range 26–73 years) with anatomical and/or histologically proven disease were included in this study. Three patients had either metastatic head-and-neck paragangliomas (HNPGLs) or multifocal PGL, and seven patients had nonmetastatic disease. Comparative evaluation included morphological imaging with CT, functional imaging with 18F-DOPA PET, and 123I-MIBG imaging including SPECT/CT. Imaging results were analyzed on a per-patient and per-lesion basis.ResultsOn a per-patient basis, 18F-DOPA PET’s detection rate for both nonmetastatic and metastatic/multifocal disease was 100%, whereas that of planar 123I-MIBG imaging alone was 10.0% and that of 123I-MIBG SPECT/CT was 20.0%. Overall, on a per-lesion basis, 18F-DOPA PET showed a sensitivity of 69.2% (McNemar p < 0.001) compared with anatomical imaging. Sensitivity of planar 123I-MIBG scintigraphy was 5.6%, and that of SPECT/CT was 11.1% (McNemar p < 0.0001). Overall, 18F-DOPA PET identified 18 lesions, and anatomical imaging identified 26 lesions; planar 123IMIBG imaging identified only 1 lesion, and SPECT/CT, 2 lesions.Conclusion18F-DOPA PET is more sensitive than is 123I-MIBG imaging, including SPECT/CT, for staging HNPGL. Combined functional and anatomical imaging (PET/CT) is indicated to exclude metastatic disease in extra-adrenal PGL.

Does ulnar nerve dislocation at the elbow cause neuropathy: What do we learn?

With great interest we read the recent article by Omejec et al., who tried to “. . .elucidate the role of ulnar nerve dislocation in the pathogenesis of ulnar neuropathy. . ..” Their study and its conclusions on ulnar nerve dislocation and/or ulnar neuropathy of the elbow (UNE) appear to be based on inconsistent study design, inconclusive data, and overinterpretation of statistical results. Apart from a minor arithmetic mistake in Table 1 (% of dislocation in group I) of their article, the only significant result is the higher incidence of (partial) dislocation of the ulnar nerve in controls with subclinical UNE; all other results are not significant (P< 0.05), despite a sizeable number of participants. Unfortunately, the emerging paradox that pathological electrodiagnostics were associated with a higher rate of nerve dislocation in control subjects but a lower rate in patients with UNE was not further elaborated. Taken at face value, these findings seem to hint at a protective effect of dislocation—a notion not easy to reconcile with our present understanding of compression neuropathy. On the topic of statistics, unfortunately no correction for multiple testing was performed. As statistics and study design should reflect the scientific question, it is not clear why only t-tests and chi-square tests were used, with no other patient/control features included in the analysis. An exploratory setting such as that described by the authors could have strongly benefitted from a multivariate analysis to determine the influence and codependence of factors such as age, gender, body mass index, occupation, duration of symptoms, cubital-tohumeral ratio, loss of fasciculation, or epineural thickening. Usually, odds ratios and confidence intervals allow for a better estimation of one factor’s influence on another; cause is nearly impossible to establish in noninterventional or diagnostic studies. However, correlation can be defined. Based on earlier data, some assumptions may be made with regard to the nature of the interaction between two or more variables; that is, it is mandatory to isolate the effect of one independent variable. Unfortunately, none of this appears to have been considered by the authors. Finally, in our opinion, Omejec and colleagues gave the impression of a prospective study, yet the study was in fact retrospective and appears to have consisted of data subsets from two previously published studies. The control group case number was identical (n 5 49), as was the number of participants with subclinical UNE (n 5 10, group III). Admittedly, this does not necessarily mean falsified data, but it must be taken into account. Even if there was no clear-cut correlation between UNE and nerve dislocation, the study did not disprove any correlation nor did it enhance our knowledge of this matter. Any conclusions drawn by the authors should be reviewed very cautiously as they are, as explained above, beyond any analytic proof.

Ultrasonography for the Diagnosis of Carpal Tunnel Syndrome in Diabetic Patients: Missing the Mark?

PURPOSE  Diabetes mellitus (DM) and carpal tunnel syndrome (CTS) are common pathologies. The diagnosis of CTS can be facilitated by the use of an ultrasound-based wrist-to-forearm ratio (WFR) of the nerve diameter. However, the applicability of WFR in DM-patients is not yet clear. MATERIALS AND METHODS  233 wrists of 153 patients were examined. Cross-sectional areas (CSA) of the median nerve were obtained using a linear array probe. The WFR was calculated. RESULTS  Diabetics with CTS had significantly lower WFR values than non-diabetics with CTS (p = 0.002). There was no difference between the WFR of diabetics with and without CTS (p = 0.06). The diagnostic accuracy between diabetics with and without CTS was low for measurements of WFR (ROC AUC = 0.630, 95 % CI 0.541 - 0.715, p = 0.011). CONCLUSION  Our findings suggest that the WFR has a low diagnostic accuracy in diabetic patients with CTS and should be used with caution in those patients. KEY POINTS   · The diagnostic accuracy of WFR is low in patients with DM. · WFR should not be used in patients with DM. · The sonographic evaluation of the median nerve in patients with DM should focus on morphological changes. CITATION FORMAT · Steinkohl F, Loizides A, Gruber L et al. Ultrasonography for the Diagnosis of Carpal Tunnel Syndrome in Diabetic Patients: Missing the Mark?. Fortschr Röntgenstr 2019; 191: 117 - 121.