Biomedical subjects

J Kromeier

Publications and source records attributed to J Kromeier.

6 recordsLinked to original sources

PubMed2007

[Conventional tomographic investigations of the reconstructed middle ear in temporal bone specimen].

BACKGROUND: In modern reconstructive middle ear surgery imaging plays an essential role as a diagnostic tool, especially in pre-operative planning. Nowadays imaging of surgical results as a matter of quality control in post-operative follow-up becomes more important. MATERIAL AND METHODS: Conventional tomography was performed in 10 temporal bone specimen using the CommCat IS 2000-system in order to evaluate anatomical structures and inserted middle ear prostheses (PORP/TORP). This imaging technique has not been used in middle ear surgery beforehand. RESULTS: Using conventional tomography characterization of anatomical structures of the temporal bone as e. g. the semicircular canals appeared to be of superior quality to comparable conventional radiographic imaging. Concerning imaging quality (contrast; resolution) conventional tomography allowed similar findings like computed tomography (CT)-scans in some of the investigated specimen while showing inferior sharpness quality due to technical reasons. Further advantages of conventional tomography in contrast to CT were the requirement of just 2.5 % of the CT's irradiation exposure, lack of metallic artefacts caused by implanted prostheses and the feasibility of distance- and angle-measurement of inserted prostheses towards the tympanic membrane which coincided extensively with the temporal bone preparation. CONCLUSIONS: Conventional tomography enables detailed anatomical imaging of the temporal bone region which outperforms conventional radiographic imaging, requires less irradiation dose than CT and helps avoid problems like metallic artefacts. This technique enhances immediate quality-control and seems to be therefore a promising tool for postoperative evaluation after reconstructive middle ear surgery.

Contrast Media↗

PubMed2006

Rotational tomography of the normal and reconstructed middle ear in temporal bones: an experimental study.

Imaging is an essential diagnostic tool in reconstructive middle ear surgery, especially in pre-operative planning. Due to ongoing improvement of imaging quality and development of new imaging techniques like e.g. rotational tomography (RT) post-operative follow-up and immediate evaluation of surgical results may become more important. The aim of this experimental study was to evaluate RT as a new tool for postoperative determination of middle ear anatomy and implant position in temporal bones. RT was performed in ten temporal bone specimen after insertion of different middle ear prostheses concerning material, shape and length (PORP; TORP; Stapes piston). An implantable hearing device (Symphonix Soundbridge) was also implanted and visualized. For comparison some specimen additionally underwent conventional computed tomography (CT), including the newest technology. Characterization of anatomical structures of the temporal bone using RT was of comparable quality to conventional CT-scans in all investigated specimen while requiring approximately 30% of the CT's irradiation exposure. Unlike CT the RT showed almost no problems due to metallic artefacts of the implanted prostheses. Furthermore RT enabled a 3-dimensional view of the temporal bone and angle determination of inserted prostheses towards the tympanic membrane and/or the malleus handle. Detailed imaging of the prostheses allowed determination of shape, material and localization within the specimen's reconstructed middle ear. The new imaging technique of RT allows precise presentation of anatomical structures and middle ear implants in temporal bones. Following these experimental results it will be our future work to evaluate this method in clinical practise.

Ear, Middle↗

PubMed2006

The use of a polytetrafluoroethylene-covered stent graft for transjugular intrahepatic portosystemic shunt (TIPS): Long-term follow-up of 100 patients.

PURPOSE: To retrospectively evaluate results and clinical outcome of transjugular intrahepatic portosystemic shunt (TIPS) after implantation of a polytetrafluoroethylene (PTFE)-covered stent graft. MATERIAL AND METHODS: The stent graft was used in 112 patients with higher risk of primary (i.e. patients with Budd-Chiari syndrome) or secondary shunt failure (patients with occlusion of a previous uncovered stent), or a complicated TIPS procedure with an imminent technical complication requiring covered stent. Patients were scheduled at 3- to 6-month intervals for duplex-sonographic control of shunt function. Radiological revision was performed in patients with a decrease in shunt function by >25%, primary non-response, or relapse of the index symptom. RESULTS: Twelve patients were lost to follow-up, and 100 patients were followed for 22+/-15 months. The actuarial rates of shunt patency were 90, 84, and 74% at 1, 2, and 3 years of follow-up, respectively. Two patients developed early (within 1 month) and 14 patients late shunt failure. Except for one transient rise in liver enzymes due to outflow obstruction by the stent graft, no technical complications were seen. Primary response to treatment was seen in 97% of patients treated for variceal bleeding and 84% of patients treated for refractory ascites. A relapse of the index symptom was seen in 13% of bleeders and 9% of patients treated for refractory ascites. CONCLUSION: TIPS created with a PTFE-covered stent graft showed favorable long-term results.

Adolescent↗

PubMed2003

Simultaneous voiding cystourethrography and voiding urosonography.

PURPOSE: To compare the diagnostic accuracy of contrast-enhanced voiding urosonography (VUS) and voiding cystourethrography (VCUG) during simultaneous performance of both examinations. MATERIAL AND METHODS: A total of 24 children, 16 girls and 8 boys, with a mean age of 3.5 years referred for reflux examination were recruited for the study. After transurethral bladder catheterization, radiographic contrast medium, followed directly by the US contrast medium, were administered. Fluoroscopic VCUG and VUS were carried out concurrently in the same patient. When 1 kidney was scanned by ultrasound, fluoroscopy was performed on the contralateral side. RESULTS: In 19 of the 47 kidney-ureter-units (KUU) vesicoureteral reflux (VUR) was detected. In 16 units the reflux was detected by both VCUG and VUS. In 3 KUUs the reflux was detected only at VCUG. All 3 cases were grade 1. Taking the VCUG as the reference standard, VUS had 84% sensitivity, 100% specificity, 100% and 90% positive and negative predictive values, respectively. CONCLUSION: A dependable comparison could be achieved by performing VCUG and VUS at the same time and under the same conditions. It reconfirmed that VUS is reliable in the exclusion or verification of reflux.

Child, Preschool↗

PubMed2002

[Relevance of magnetic resonance imaging for the staging and follow up of lymph node pathologies in adults with primary malignant lymphomas].

Lymph node histology and staging with cross sectional imaging remains basis for the treatment planning in primary malignant lymphoma. Contrast enhanced computed tomography is considered to be gold standard. However, MRI is equally able to provide staging and follow up in the same quality as helical CT, as several studies and clinical experience show. MRI is considered as the superior imaging modality for extranodal lymphoma. Advantages of MRI are that it works without ionizing radiation and contrast media;however, MRI is more expensive and time consuming. However, both imaging modalities are limited by the fact that the differentiation of affected and non affected lymph nodes is based on size only. Also the results of recent clinical studies with USPIOs (SINEREM((R):)) for intravenous MR lymphography in primary malignant lymphoma do not look promising. Despite these disadvantages of MRI, for young patients with malignant lymphoma radiation protection should be taken into account because of frequent imaging in staging and follow up.

Adult↗

PubMed2001

Influenza A virus infection of mice induces nuclear accumulation of the tumorsuppressor protein p53 in the lung.

To investigate whether the tumor suppressor p53 protein, an indicator of DNA damage and cell stress, accumulates in the course of influenza-virus-induced murine pneumonia at the site of inflammation, female BALB/c mice were infected each with 5 x 10(4) infectious units of influenza virus A, strain Puerto Rico (PR) 8, by instillation into the nose and the pharynx. Two days later the mice became sick. Three and 6 days after infection the lungs of sacrificed infected and uninfected mice were examined. We assessed the presence and localisation of inflammation, the expression of influenza viral and p53 protein, as well as of the WAF1/Cip1/SDI gene product p21. Further, the appearance of nitrotyrosine, as an indicator of the formation of peroxynitrite, and eventually of apoptotic cells was examined. No significant nuclear p53 accumulation was found in influenza virus-infected murine cells in vitro. The results show, that in the course of influenza A virus-mediated murine pneumonia inflammatory bystander cells may cause activation of the tumor suppressor protein p53, due to oxidative stress and DNA damage, with ensuing p53-dependent upregulation of p21. Apoptosis is then mainly due to these indirect processes, with possible involvement of p53.

Animals↗