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Biomedical subjects

Manfred Wehrmann

Publications and source records attributed to Manfred Wehrmann.

At least 19 recordsLinked to original sources

Extradural ependymal tumor with myxopapillary and ependymoblastic differentiation in a case of Schinzel-Giedion syndrome.

Primary extradural ependymomas are rare neoplasms usually of the myxopapillary type. Reports on malignant primary extradural ependymal tumors are exceptionally rare. We here report on a 3-year-old boy with Schinzel-Giedion syndrome (SGS), who presented with lumbar spina bifida occulta and a progressive extraspinal lesion in the subcutaneous sacrococcygeal region. Microscopic examinations revealed an uncommon ependymal tumor with well-differentiated regions reflecting myxopapillary ependymoma and highly anaplastic regions with numerous mitoses, necroses, ependymal rosettes and ependymoblastic rosettes. Final neuropathologic diagnosis was an extraspinal anaplastic ependymal tumor with myxopapillary and ependymoblastic differentiation, corresponding to WHO grade IV. SGS is a very rare disorder with a likely autosomal recessive pattern of inheritance. So far, 42 cases have been reported, among them 7 were diagnosed to have malignant neoplasms, including three malignant sacrococcygeal teratomas, two sacrococcygeal primitive neuroectodermal tumors (PNET), one hepatoblastoma and one malignant kidney tumor. The present case is the first report on an ependymal tumor with a mixture of myxopapillary, anaplastic and ependymoblastic features and the first report on an ependymal tumor arising on the genetic background of SGS.

Central Nervous System Neoplasms↗

Irradiation-induced pneumonitis mediated by the CD95/CD95-ligand system.

Pneumonitis is a dose-limiting side effect of radiotherapy. However, the underlying mechanisms of irradiation-induced pneumonitis are unclear. Several observations suggest that the CD95/CD95-ligand (CD95L) system is involved in this process. Therefore, we examined the development of pneumonitis in CD95- and CD95L-deficient and wild-type mice after single irradiation with 0 or 12.5 Gy by measuring breathing frequency, pulmonary resistance, and histopathologic changes. Although wild-type mice developed pathognomonic alterations characteristic of pneumonitis (judged by alveolar wall thickness, interstitial edema, and interstitial and peribronchial inflammation) that paralleled increased breathing frequency ratio on days 5-70 (P < .03) with a maximum at day 37 (12.5 Gy, mean ratio = 1.05, 95% confidence interval [CI] = 1.01 to 1.08; P = .004 versus 0 Gy, mean ratio = 0.997, 95% CI = 0.976 to 1.02; P = .05) and pulmonary resistance (day 42, 12.5 Gy, mean = 0.51, 95% CI = 0.44 to 0.58 versus 0 Gy, mean = 0.40, 95% CI = 0.32 to 0.47; P = .03) after irradiation, no such changes were detected in CD95- or CD95L-deficient mice. This report demonstrates for the first time, to our knowledge, that the CD95/CD95L system is important for the development of irradiation-induced pneumonitis.

Animals↗

Spontaneous thoracic air-leakage syndrome in patients following allogeneic hematopoietic stem cell transplantation: causes, CT-follow up and patient outcome.

OBJECTIVE: The purpose of this article is to describe and illustrate the acute and follow-up imaging features, clinical constellation and outcome of patients with thoracic air-leakage syndrome following allogeneic hematopoietic stem cell transplantation (allo-HCT). METHODS: Patients with evidence of thoracic air-leakage, i.e. spontaneous pneumomediastinum, spontaneous pneumothorax or interstitial emphysema after allo-HCT were retrospectively identified by a chart review. Acute and follow-up morphology, duration and patient outcome were analyzed on CT (HRCT or MSCT with HR-reconstructions). Correlation was made with histological results of transbronchial biopsy. RESULTS: The 6 patients included (3 male and 3 female, 14-64 years old) with thoracic air-leakage after allo-HCT all had histologically proven bronchiolitis obliterans (BO) or bronchiolitis obliterans organizing pneumonia (BOOP). Thoracic air-leakage consisted of spontaneous pneumomediastinum associated with active invasive pulmonary aspergillosis (IPA) in 4/6 and spontaneous pneumothorax or interstitial emphysema each in 1/6 patients. Duration of thoracic air-leakage was 7-135 days. Of the patients with spontaneous pneumomediastinum, 3/4 died of IPA. One patient survived until complete regression of spontaneous pneumomediastinum. One patient died 7 days after spontaneous pneumothorax and one survived developing chronic interstitial emphysema. CONCLUSION: In all cases, thoracic air-leakage was associated to BO or BOOP. In the majority of cases with additional IPA, thoracic air-leakage is more indicative for severity of pulmonary disease than a life-threatening entity itself.

Acute Disease↗

Use of a hanging-weight system for isolated renal artery occlusion during ischemic preconditioning in mice.

Renal failure from ischemia contributes to morbidity and mortality. Ischemic preconditioning (IP) represents a powerful strategy for kidney protection, and recent advances in transgenic mice may help elucidate its molecular mechanisms. However, murine IP is technically challenging and experimental details significantly influence results. Thus we developed a novel model for renal IP using a hanging-weight system for isolated renal artery occlusion. In contrast to previous models, this technique eliminates the need for clamping the vascular pedicle (artery/vein). In fact, assessment of renal injury after different time periods of ischemia (10-60 min) revealed highly reproducible increases in plasma creatinine and potassium levels, while creatinine clearance, urinary flow and potassium/sodium excretion were significantly attenuated. Using different numbers of IP cycles, we found maximal protection with four cycles of 4 min of ischemia-reperfusion. In contrast, no significant renal protection was observed with IP of the vascular pedicle. To assess transcriptional responses in this model, we isolated RNA from preconditioned kidneys and found time-dependent induction of erythropoietin mRNA and plasma levels with IP. Taken together, this model provides highly reproducible renal injury and protection by IP, thus minimizing variability associated with previous techniques based on clamping of the renal pedicle. Further studies on renal ischemia/IP in mice may consider this technique.

Animals↗

Choroid plexus tumors differ from metastatic carcinomas by expression of the excitatory amino acid transporter-1.

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.

Adenocarcinoma↗

Solitary pulmonary nodules: association between signal characteristics in dynamic contrast enhanced MRI and tumor angiogenesis.

PURPOSE: To estimate the association between signal characteristic of dynamic enhanced MRI using curve types and angiogenesis in solitary pulmonary nodules. MATERIALS AND METHODS: Thirty-six patients with a solitary pulmonary nodule (SPN) ranging in size from 6 to 37 mm (median 17 mm) underwent dynamic contrast enhanced MRI with a time interval of 10 s over a total period of 4 min. Resulting from the time-intensity curves four different enhancement curve profiles (A-D) were defined: type A with strong increase followed by early washout, type B with strong increase without washout, type C with slow increase and type D without relevant increase. Maximum peak (Pmax), slope of the first bolus transit (slope) and washout were calculated. Microvessel densities (MVD) were counted at the margins and at the center of the nodules. The mean MVD of each nodule was calculated. Enhancement characteristics were correlated with MVD grouped by diagnosis and by curve types. Curve types were correlated with the score of vascular endothelial growth factor (VEGF). RESULTS: The frequency of malignancy was 55% (20/36). Using curve types for differentiation between malignant and benign SPN, the sensitivity, specificity and accuracy were 100%, 75% and 89%, respectively. The correlation between Pmax and MVD(mean) for all nodules was moderate (r(s)=0.4, P=0.02). A relevant correlation was found between Pmax and MVD(margin) in curve type A (r(s)=0.63; P=0.04) and Pmax and MVD(mean) in curve type C (r(s)=0.86; P=0.006). No positive correlation was found between Pmax and MVD (mean, center and margin) in curve type B. No significant correlation was found for slope and washout. VEGF score correlated positively with curve types (r(s)=0.67; P<0.001). CONCLUSION: A relevant association between perfusion curve profiles and angiogenesis was found in malignant nodules having early washout and in benign lesion with a slow increase of enhancement. In cases of strong signal increase without washout additional factors for enhancement must be considered. The use of curve profiles could allow for the estimation of the extent of VEGF.

Adenocarcinoma↗

Theophylline improves early allograft function in rat kidney transplantation.

Several previous studies have demonstrated a beneficial effect of the adenosine receptor (AdoR) antagonist theophylline in different forms of acute renal failure in laboratory animals and in humans. Therefore, we wanted to test whether theophylline can also improve impaired allograft function following ischemia reperfusion injury in experimental kidney transplantation (KT). Orthotopic transplantation of the left kidney was performed from Fisher 344 into Lewis rats. All transplanted rats received daily cyclosporine (5 mg/kg). The effect of theophylline treatment (10 mg/kg) on graft function was compared with appropriate controls on day 5 after KT by assessment of glomerular filtration rate (GFR) (inulin clearance). On day 5, GFR of allografts in control rats was 0.23 +/- 0.05 ml/min/g kidney weight (n = 10) compared with 0.50 +/- 0.09 ml/min/g in rats receiving theophylline (n = 9, p < 0.01), representing a 2-fold increase in GFR. Renal AdoR A(1) mRNA content was significantly increased in both KT groups compared with their respective control groups, whereas mRNA of AdoR A(2a), A(2b), and A(3) were found to be unchanged. Theophylline did not affect significantly interstitial infiltration of the graft by monocytes/macrophages and T-cells. Likewise, serum cytokines [interleukin (IL)-2, IL-6, IL-10, tumor necrosis factor-alpha] and erythropoietin plasma levels were not different among the allograft groups. The present study demonstrates that theophylline remarkably improved early renal allograft function in rats undergoing KT without influencing cytokine serum patterns or tissue inflammation. Since theophylline is a commonly used medication in humans, clinical studies in patients undergoing KT are warranted.

Animals↗

Giant mullerian duct cyst with malignant transformation in 15-year-old boy.

We present a case of a giant mullerian duct cyst with components of clear cell adenocarcinoma in a 15-year-old boy. Complete tumor resection was achieved in two steps. The presented case with a combination that has never been described before may change the perspective of treatment approaches for this rare entity.

Adenocarcinoma, Clear Cell↗

Atrial linear lesions: feasibility using cryoablation.

BACKGROUND: Long linear lesions are created in the left atrium to modify the atrial substrate, thereby curing atrial fibrillation. The creation of long linear left atrial lesions using radiofrequency (RF) ablation is time consuming and difficult. Furthermore, it might result in significant complications. Cryoablation might overcome some of the disadvantages of RF ablation. Therefore, the aim of our study was to assess whether the creation of a long linear lesion is possible using cryotherapy. METHODS: A right atrial septal linear lesion was created in six pigs (median weight: 50 kg; range: 40-60 kg). The ablation procedure was performed with a 7-F Freezor cryocatheter. The nonfluoroscopic mapping system LocaLisa was used as a navigation tool. At each point, freezing was maintained at the lowest attainable temperature (-75 degrees C) for 4 minutes. The CARTO system was used for the evaluation of the linear lesions. Furthermore, all animals were sacrificed immediately after the ablation procedure and a postmortem examination of the lesions was performed. Additionally, an analysis of the amplitudes of the intracardiac electrograms registered via the ablation catheter was performed before and after the ablation procedure. RESULTS: A right atrial septal linear lesion could be created successfully in all six pigs. For the performance of this ablation line, a median number of 16 cryoapplications (range, 11-26) was necessary. The amplitudes of the intracardiac electrograms registered via the ablation catheter decreased significantly after ablation. The CARTO bipolar voltage map revealed very low potentials along the ablation line and showed a sharply demarcated ablation area at the septum in all pigs. Further analysis of the CARTO map revealed an incomplete conduction block in all cases. Most of the pigs had a small gap close to the fossa ovalis. The postmortem examination of 2,3,5-triphenyl-tetrazolium chloride-stained specimens showed sharply demarcated lesions without any ulcerations. There were no major complications during the procedure. CONCLUSIONS: The creation of long linear lesions using cryoablation is feasible and safe. Lesion characteristics are different and more favorable than those created by RF. However, the aim of creating a transmural lesion and a complete conduction block remains an unsolved problem even with current cryoablation techniques. Nevertheless, growing experience and technical improvements might overcome some of the current limitations of this new technique.

Animals↗

Cytomegalovirus pneumonia after stem cell transplantation: correlation of CT findings with clinical outcome in 30 patients.

OBJECTIVE: The purpose of our study was to assess the correlation between early high-resolution CT findings of cytomegalovirus (CMV) pneumonia in patients with blood disorders and their clinical outcomes. CONCLUSION: The initial high-resolution CT findings in immunocompromised patients with CMV pneumonia seem to predict the patient's outcome being unfavorable in those forms of disease beginning mostly bilaterally as diffuse or patchy ground-glass opacity followed by progressive air-space consolidation. Also, a change in the CT morphology of pulmonary lesions toward diffuse ground-glass opacity seems to correlate with an unfavorable disease course.

Adult↗

Prevention of carotid artery restenosis after sirolimus-coated stent implantation in pigs.

BACKGROUND AND PURPOSE: To test the feasibility of self-expanding drug-coated nitinol stents for prevention of restenosis in an animal model. Stent implantation in the carotid artery (CA) has been shown to be feasible for treatment of CA stenosis. Even though the restenosis rate in CA is reported to be lower than in the coronary and peripheral arteries, problems may arise with increasing numbers of treated patients and lengthier follow-up. METHODS: After predilatation with 8-mm balloons, 8 Goettinger minipigs were randomly selected to receive a sirolimus-eluting self-expanding nitinol stent (7 mm/80 mm) as well as the same stent without sirolimus/polymer coating in the right or left CA. Aspirin was given starting 3 days before the intervention and administered for an additional 4 weeks. Clopidogrel was administered for 10 days. RESULTS: After 6 weeks, 2 subacute occlusions were observed in both groups. In the remaining vessels, the neointima was significantly reduced by sirolimus/polymer-coated stents (5.9+/-2.5 versus 0.7+/-1.0 mm2). CONCLUSIONS: Sirolimus self-expanding nitinol stents may be an effective tool in reducing neointimal formation in CA.

Alloys↗

A complicated case of bilateral cystic nephroma in a 16-month-old boy.

We describe a case of a progressive bilateral cystic nephroma (BCN) in a child undergoing a multistaged surgical procedure. After partial resection of the left sided tumor, a progress occurred on that side and the left kidney had to be removed 10 weeks later. After 35 months a tumor progression was observed on the right side together with an ureteral obstruction leading to a decreased renal function. In a third operation a complete tumor resection on the right side was achieved through longitudinal partial nephrectomy, reconstruction of the renal pelvis, and reanastomosis of the reconstructed pelvis and ureter. The patient showed no evidence of the disease at 28 months of follow-up. The presented case provides an evidence that in BCN a tumor progress may occur after multistaged surgical approaches. A single-staged complete tumor resection with renal salvage techniques seems indicated.

Disease Progression↗

Disseminated epitheloid hemangioendothelioma mimicking symptoms of systemic vasculitis.

BACKGROUND: Epitheloid hemangioendothelioma is a rare malignant tumor which can involve bones, liver, lungs, kidneys, deep soft tissue, muscles, dermis, and central nervous system. Multifocal disease occurs in 10% of the cases. The clinical presentation results from occlusion of small blood vessels due to the disease itself or as a paraneoplastic syndrome. CASE REPORT: We present a patient with symptoms suggesting systemic vasculitis (ESR and CRP elevated, weight loss, arthralgia, livedoid rash, and skin ulcerations) who finally was diagnosed having a disseminated epitheloid hemangioendothelioma when PET scan revealed hypermetabolic multifocal skeletal and soft tissue lesions. DISCUSSION: Diseases mimicking systemic vasculitis and the value of PET in this setting are discussed.

Aged↗

Effect of dopamine D3 receptor blockade on renal function and glomerular size in diabetic rats.

Dopamine D2-like receptors, including D2, D3, and D4 receptors, are involved in the regulation of glomerular hyperfiltration due to diabetes mellitus. These hemodynamic alterations represent a risk factor for the later development of diabetic nephropathy. The aim of the present study was to determine whether the D3 receptor subtype modulates the diabetes-induced increase in glomerular filtration rate (GFR) in rats. Renal function was studied in Sprague-Dawley rats 14 days after induction of a moderate diabetes mellitus (DM) by streptozotocin and in non-diabetic controls (CON). Rats were orally treated either with the peripherally acting, selective dopamine D3 receptor antagonist BSF 135170 (BSF, 10 mg/kg per day for 2 weeks) or with vehicle (VHC). Perfusion-fixed kidneys were used for estimation of glomerular volume. In conscious rats, which were treated with BSF, the DM-induced increase in fluid intake, urinary output, and renal sodium excretion was significantly less pronounced than in the vehicle group (DM-VHC). In the clearance experiments, GFR in CON was about 0.84+/-0.04 ml/min per 100 g body weight. The DM-VHC group presented a significant glomerular hyperfiltration (1.09+/-0.04 ml/min per 100 g body weight). Treatment with BSF significantly lowered GFR towards levels of CON. The estimated glomerular volume was 0.73+/-0.03 x 10(6) microm3 in the CON-VHC group and 0.86+/-0.04 x 10(6) microm3 in the DM-VHC animals. Interestingly, treatment with BSF decreased the glomerular volume in both groups. Irrespective of BSF treatment, kidney wet weight related to body weight was about 36% higher in DM animals compared with CON animals. We conclude that dopamine D3 receptors represent a target for the modulation of diabetes-induced glomerular hyperfiltration. Therefore, the results encourage the testing of the possible beneficial effects of long-term D3 receptor blockade on the development of diabetic nephropathy.

Animals↗

Significance of the "halo" sign for progression and regression of nodular pulmonary amyloidosis: radiographic-pathological correlation (2005:6b).

We describe a case of a systemic amyloidosis of kappa-AL type, presenting at CT as focal lung parenchymal nodules or areas of consolidation with or without a halo,showing different sizes and morphologic kinetics at follow-up. Lesions accompanied by a halo revealed faster progression and earlier response to chemotherapy with almost complete resolution after high dose therapy with a cytostatic alkylating agent(Melphalan) and autologous peripheral stem cell transplantation than their counterparts without a halo. Amyloid deposition was histologically confirmed, and severe inflammatory activity was found in and at the margins of the amyloidomas, the latter correlating in CT with the halo sign. In our case, this sign had a high prediction for growth kinetics and response to therapy of pulmonary amyloid.

Amyloid↗

Synchronous gastrointestinal and musculoskeletal manifestations of different subtypes of inflammatory myofibroblastic tumor: CT, MRI and pathological features.

We describe a case of an unusual multicentric appearance of an inflammatory myofibroblastic tumor, consisting of multiple gastrointestinal masses with different growth patterns and simultaneous, distant, musculoskeletal manifestations. CT and MR imaging features demonstrated a different degree of lesion enhancement, which proved histologically to be related to an alternation of predominantly spindle cell areas with a myxoid-vascular IMT subtype. A clear separation of the imaging characteristics of this tumor's subtypes by correlation with the pathology was not possible because of the mixed histologic character of the tumor in all its locations. However, MRI signal in the T2-weighted sequence was lower in the spindle cell variant localized predominantly in the musculoskeletal system, while the gastrointestinal predominantly myxoid-vascular counterparts showed slightly higher signal in the T2-weighted sequence.

Aged↗