Katharina Holzer

Real-time Elastography and Contrast-Enhanced Ultrasound for the Assessment of Thyroid Nodules

OBJECTIVE Work-up of thyroid nodules remains challenging. Recent technologies enable determination of tissue elasticity and perfusion using ultrasound devices. The aim of the present study was to evaluate real-time elastography (RTE) and contrast-enhanced ultrasound with Sonovue (CEUS) for the differentiation of benign and malignant thyroid nodules. MATERIALS AND METHODS Inclusion criteria were: nodules ≥1 cm, non-functioning or hypo-functioning on radionuclide scanning, and cytological/histological assessment. All patients received conventional ultrasound, RTE and CEUS. RTE was classified as: Elasticity-Score (ES)1 = soft, ES2 = predominantly soft, ES3 = predominantly hard, ES4 = hard nodule. CEUS-video clips were digitally recorded and analyzed using time-intensity-curves within selected regions-of-interest. RESULTS Fifty-three nodules in 50 patients were available for analysis. Forty-six nodules were benign on cytology/histology, 6 nodules were papillary carcinoma and one nodule was a follicular carcinoma. Nodule margin irregularity was the ultrasound pattern most predictive of malignancy with sensitivity 57% (95% confidence interval: 18-90%) and specificity 85% (71-94% p<0.05). When using ES3&4 for the diagnosis of malignant nodules sensitivity and specificity were 86% (42-99.7%) and 87% (75-95%), respectively (p = 0.0003). The only malignant nodule missed with RTE was a follicular carcinoma. Sensitivity for the diagnosis of papillary carcinoma therefore was 100%. No specific CEUS pattern could be identified to differentiate between benign and malignant nodules. CONCLUSIONS RTE seems to be a useful tool in the work-up of thyroid nodules to exclude papillary thyroid cancer. However, follicular carcinoma remains a challenging problem. CEUS did not improve the characterization of thyroid nodules in this preliminary study.

Acoustic Radiation Force Impulse Imaging for Differentiation of Thyroid Nodules

Background Acoustic Radiation Force Impulse (ARFI)-Imaging is an ultrasound-based elastography method enabling quantitative measurement of tissue stiffness. The aim of the present study was to evaluate sensitivity and specificity of ARFI-imaging for differentiation of thyroid nodules and to compare it to the well evaluated qualitative real-time elastography (RTE). Methods ARFI-imaging involves the mechanical excitation of tissue using acoustic pulses to generate localized displacements resulting in shear-wave propagation which is tracked using correlation-based methods and recorded in m/s. Inclusion criteria were: nodules ≥5 mm, and cytological/histological assessment. All patients received conventional ultrasound, real-time elastography (RTE) and ARFI-imaging. Results One-hundred-fifty-eight nodules in 138 patients were available for analysis. One-hundred-thirty-seven nodules were benign on cytology/histology, and twenty-one nodules were malignant. The median velocity of ARFI-imaging in the healthy thyroid tissue, as well as in benign and malignant thyroid nodules was 1.76 m/s, 1.90 m/s, and 2.69 m/s, respectively. While no significant difference in median velocity was found between healthy thyroid tissue and benign thyroid nodules, a significant difference was found between malignant thyroid nodules on the one hand and healthy thyroid tissue (p = 0.0019) or benign thyroid nodules (p = 0.0039) on the other hand. No significant difference of diagnostic accuracy for the diagnosis of malignant thyroid nodules was found between RTE and ARFI-imaging (0.74 vs. 0.69, p = 0.54). The combination of RTE with ARFI did not improve diagnostic accuracy. Conclusions ARFI can be used as an additional tool in the diagnostic work up of thyroid nodules with high negative predictive value and comparable results to RTE.

Vitamin D receptor polymorphisms in differentiated thyroid carcinoma.

BACKGROUND Vitamin D receptor (VDR) expression has been shown to be upregulated in several tumors and is supposed to represent an important endogenous response to tumor progression. To investigate the role of the VDR gene and its influence on 25(OH)D(3) and 1,25(OH)(2)D(3) plasma levels in thyroid carcinoma, we analyzed four VDR polymorphisms in patients and healthy controls (HC). METHODS Patients with thyroid carcinoma (n = 172) (n = 132 for papillary and n = 40 for follicular) and HC (n = 321) were genotyped for the ApaI (rs7975232), TaqI (rs731236), BsmI (rs1544410), and FokI (rs10735810) polymorphisms within the VDR gene and correlated with 25(OH)D(3) and 1,25(OH)(2)D(3) plasma levels. RESULTS The genotypes AA of the ApaI (rs7975232) and FF of the FokI (rs10735810) polymorphisms were significantly less frequent (12.5% vs. 35.2% and 25% vs. 42.1%, respectively, both corrected p [p(c)] = 0.04) in patients with follicular thyroid cancer (FTC) than in HC. Additionally, the haplotypes, Ta (57.5% vs. 41.4%; p(c) = 0.0207), af (24.6% vs. 14.3%; p(c) = 0.0116), Tab (51.1% vs. 36.8%; p(c) = 0.0495), and Tabf (18.7% vs. 13.6%; p(c) = 0.0240) were more frequent, whereas the haplotypes AF (17.1% vs. 37.2%; p(c) = 0.0008), BF (11.4% vs. 31.9%; p(c) = 0.012), tF (7.9% vs. 25.5%; p(c) = 0.0016), and tABF (7.6% vs. 23%; p(c) = 0.0115) were less frequent in the FTC patients compared to HC. Neither genotype nor haplotype frequencies differed between patients with papillary thyroid cancer (PTC) and HC. Further, individuals with PTC and FTC had a significantly lower level of circulating 1,25(OH)(2)D(3) compared to controls. In contrast, no differences of the 25(OH)D(3) concentration between patients and HC were observed. VDR polymorphisms were not associated with 25(OH)D(3) and 1,25(OH)(2)D(3) plasma levels. CONCLUSIONS Lower circulating levels of 1,25(OH)(2)D(3) are observed in patients with differentiated thyroid carcinoma. Further, while the alleles AA and FF of the ApaI (rs7975232) and FokI (rs10735810) VDR polymorphisms and the haplotype tABF confer to protection from follicular carcinoma, the haplotype Tabf appeared to be associated with an increased FTC risk. Since this is the first report associating VDR polymorphisms with thyroid carcinoma, these findings need to be confirmed in studies with larger numbers of patients.

Markov cohort simulation study reveals evidence for sex-based risk difference in intensive care unit patients

BACKGROUND Despite great advances in intensive care medicine, sepsis still is the leading cause of death. Different strategies have been developed to file the patient data into scoring systems, primarily to predict the outcome. The Markov simulation-predominantly used in economic science to describe chains of events depending on and influencing each other-seems to be an interesting and new approach in analyzing the course of disease of critically ill patients in an intensive care unit (ICU). Using such a Markov model, this study analyzes data from 660 surgical ICU patients, 44 of whom died of sepsis. METHODS A three-state Markov model (integrating sepsis, adult respiratory distress syndrome, and mortality) was constructed to describe the course of disease of critically ill patients in defined cycles and to develop the risk profile of different groups of patients. The model enables the comparison between age- and sex-related survival rates and shows the difference in life expectancy compared with an average untreated standard population. RESULTS Women aged up to 30 years (G1F) show the best prognosis (mortality after 19 cycles 8.3%). On the contrary, the corresponding male group (G1M) demonstrates the worst outcome (mortality after 19 cycles 57.7 %). CONCLUSIONS The findings of this study fit into the current discussion that female patients are better positioned to meet the challenge of sepsis.

Phagocytosis by Emigrated, Intra-Abdominal Neutrophils Is Depressed during Human Secondary Peritonitis

The phagocytic function of neutrophils is a crucial element in host defense against invading microorganisms. Patients with diffuse peritonitis depend on adequate reactivity of neutrophils, in particular locally in the peritoneal cavity as well as in the circulation. This study examined phagocytosis as well as numerical expression of Fcγ I–III (CD16, CD32, CD64) and complement receptors (CD18, CD35) of emigrated, intra-abdominal and circulating neutrophils during human secondary peritonitis using fluorescence-activated cell analysis. Optimally opsonized E. coli bacteria were used independently of the well-known low level of opsonic molecules during peritonitis. Compared with controls (abdominal surgery without peritonitis), the percentage of emigrated neutrophils which engulfed E. coli bacteria was significantly depressed until 48 h after diagnosis of, and surgery for, peritonitis. When patients with complicated peritonitis (septic shock, multiple organ failure) were compared with patients without complications, phagocytosis was even more depressed in patients with complications. Numerical expression of CD64 (Fcγ RI) and CD35 (CR1) increased significantly on emigrated polymorphonuclear leukocytes (PMNs) during peritonitis when compared to controls. There was no difference in CD18 and CD32 (Fcγ RII) expression between the two groups. Numerical expression of CD16 (Fcγ RIII) on emigrated PMNs decreased significantly in peritonitis. This was more pronounced in patients with complicated peritonitis. We conclude that there is a long-lasting depression of phagocytosis by emigrated PMNs during peritonitis, independent of the opsonic activity. Our data suggest that decreased phagocytosis might be correlated to the profound drop in CD16 on these cells.

Data quality aspects of a database for abdominal septic shock patients

Since many years, medical researchers have investigated the mechanisms that may cause a septic shock. Despite many approaches that analyzed smaller parts of the relevant data or single variables, respectively, no larger database with all the possible relevant data existed. Our work was to bridge this gap. We built a large database for abdominal septic shock patients. While building it, we were confronted with many problems concerning the database realization and the data quality. Thus, we will demonstrate how we built our database and how we assured data quality. This is of interest for all medical or computer scientists who are concerned with building medical databases with retrospective data, e.g. for data mining purposes.

Impaired vitamin D activation and association with CYP24A1 haplotypes in differentiated thyroid carcinoma.

BACKGROUND Common polymorphisms of the vitamin D receptor gene have been reported to affect the risk of breast, colon, prostate, and differentiated thyroid cancer (DTC), but polymorphisms within the genes of vitamin D metabolizing enzymes have not been studied in DTC. The aim of the present study was to investigate the genes for vitamin D enzymes in patients with DTC and healthy controls (HC) as well as the vitamin D (25-hydroxyvitamin D(3), and 1,25-hydroxyvitamin) status. METHODS German patients (n=253) with DTC (papillary thyroid carcinoma [PTC] and follicular thyroid carcinoma [FTC]) and HC (n=302) were genotyped for polymorphisms within the vitamin D metabolizing enzymes such as 25-hydroxylase (CYP2R1[rs12794714, rs10741657]), 25-hydroxyvitamin D-1α-hydroxylase (CYP27B1[rs10877012, rs4646536]), and 25-hydroxyvitamin D 24-hydrolase (CYP24A1[rs927650, rs2248137, rs2296241]). Furthermore, the 25-hydroxyvitamin D(3) [25(OH)D(3)] and 1,25-hydroxyvitamin [1,25(OH)(2)D(3)] plasma levels were measured by a radioimmunoassay. RESULTS There was no difference in the genotypes; however, the CYP24A1 haplotype analysis showed that rs2248137C/rs2296241A (13.1% vs. 19.1%; corrected p [pc]=0.04) was less frequent in the PTC, whereas the haplotypes rs2248137C/rs2296241G (56.0% vs. 41.9%; pc=0.03), rs927650C/rs2296241G (22.5% vs. 8.4%; pc=1.6×10(-3)), and rs927650C/rs2248137C/rs2296241G (21.1% vs. 7.3%; pc=1.5×10(-3)) were more frequent in the FTC compared with HC. Furthermore, if patients and controls were grouped according to four 25(OH)D(3) categories (severely deficient, deficient, insufficient, and sufficient), then the patients with both DTC subtypes had significantly lower levels of circulating 1,25(OH)(2)D(3), especially in the group with a deficient 25(OH)D(3) status compared with the controls. Although the polymorphisms showed no differences stratified for the four 25(OH)D(3) categories, the activation status by 1,25(OH)(2)D(3) differed significantly depending on the genotypes of the investigated CYP24A1 polymorphisms. CONCLUSIONS A higher risk for DTC is conferred by haplotypes within the CYP24A1 gene, low circulating 25(OH)D(3) levels (deficiency), and a reduced conversion to 1,25(OH)(2)D(3). These results confirm and extend previous observations and also support a role of the vitamin D system in the pathogenesis of DTC. How deficient 25(OH)D(3) levels in combination with certain CYP24A1 haplotypes affect vitamin D activation is the subject of future studies.

Fatal haemorrhage due to extensive fragility of medium- and large-sized arteries and veins in a young patient with neurofibromatosis 1

BACKGROUND Neurofibromatosis type 1 (NF1) is one of the most frequently inherited diseases. Vascular manifestations have been reported, mostly concerning stenosis of the renal artery or spontaneous rupture of single arteries. Also, venous aneurysms have been reported. METHODS We present clinical and pathological findings of a young patient with NF1 with lethal bleeding due to spontaneous rupture of a lumbal and renal artery. RESULTS High fragility of several arteries as well as veins in the abdominal and pelvic arterial and venous system resulted in a destroyed vessel structure caused by invading neurogen fibres. CONCLUSIONS In rare cases, NF1 is associated with a severe systemic vasculopathy concerning the arterial and venous vascular system.

Significantly high expression of platelet-derived growth factor (PDGF) in benign nodules of the thyroid: relevance in the development of goitre recurrence?

PurposePlatelet-derived growth factor (PDGF) is a critical regulator of cell proliferation and influences the development of tumors. The role of PDGF in benign thyroid diseases is presently not well-determined. The purpose is to evaluate PDGF isoforms and receptors in primary culture of thyrocytes isolated from human thyroid tissue.MethodsForty patients with uninodular (n = 11), multinodular (n = 15) and recurrent goitre (n = 14) were investigated. Nodular and corresponding paranodular thyroid tissues were characterized. RNA and protein were extracted from primary thyrocyte monoculture. RT-PCR, western blot and ELISA were performed to evaluate PDGF isoforms AA, BB, CC, DD and PDGF receptors α and β.ResultsSignificantly higher mRNA expression of PDGF-AA, -BB, -CC and PDGFR molecules α and β was measured by RT-PCR in thyrocytes from uninodular and recurrent nodular tissue compared with corresponding paranodular tissue. Elevated PDGF protein and PDGFR-α and -β were confirmed by western blot. Likewise, higher secretion of PDGF-AA and -BB was detected in the supernatant of thyrocyte culture from all nodular tissue compared with paranodular tissue. Interestingly, comparison of nodular and corresponding paranodular tissues in multinodular goitre did not show significant difference of expression levels of PDGF isoforms or receptors.ConclusionThese findings suggest that the overexpression of PDGF isoforms and receptors may play a crucial role in the development of thyroid nodules and recurrent goitre.

Cirrhosis serum induces a nitric oxide-associated vascular hyporeactivity of aortic segments from healthy rats in vitro

Objective Arterial vasodilation with concomitant hyperdynamic circulation are common findings in liver cirrhosis. Nitric oxide acting at a local level has been suggested to be pathophysiologically relevant in this context. Several systemic factors in conjunction with nitric oxide might interfere with the observed phenomena. Design The study has been designed to demonstrate the influence of cirrhotic serum on the nitric oxide system and vascular contractility. Methods The contractile response of aortic segments from healthy rats was studied in vitro after incubation with serum of healthy and cirrhosis-induced rats (1 week, 2 weeks, 3 weeks and 4 weeks after bile duct ligation). A cumulative dose response curve to phenylephrine (10−–10−4 mol) was established before and after incubation with nitric oxide synthesis blocker Nω-nitro-L-arginine, the more selective aminoguanidine (nitric oxide synthase [NOS]-2 inhibitor) and W7 (NOS-3 inhibitor). NOS-2 expression in incubated aortic rings was evaluated by Western blot analysis. Results A 4-hour incubation with serum of cirrhosis-induced rats reduced the maximum contractile response to phenylephrine to 66.8 ± 9.1% after 1 week, 50.4 ± 7.8% after 2 weeks, 43.2 ± 2.8% after 3 weeks and 35 ± 5.2% after 4 weeks of bile duct ligation. This reduction in the contractility response to phenylephrine was completely reversed by blocking nitric oxide synthesis with Nω-nitro-L-arginine and aminoguanidine, but not after W7. Incubation with cirrhotic serum induced NOS-2 expression in aortic rings. In Western blot analysis, the most intensive signal for NOS-2 protein was obtained in rings incubated with serum from rats 3 weeks and 4 weeks after induction of cirrhosis. Conclusions Cirrhotic serum decreases the contractile response to phenylephrine even in an early stage of secondary cirrhosis. Reversibility of this effect after nitric oxide synthesis blockade suggests an induction of nitric oxide synthesis by systemic factors as a major point in vascular hyporeactivity to vasoconstrictors in cirrhosis.