Biomedical subjects
Publications and source records attributed to U Gehling.
This article discusses the clinical significance of bone marrow metastases and the current methods being used to detect tumor cells in marrow. The strategies being investigated for eradicating cancer cells from marrow in patients receiving hematopoietic cell autografts also are reviewed.
High-dose chemotherapy with autologous hematopoietic progenitor cell support is increasingly used to treat a variety of malignant diseases. A drawback of this technique is the potential for infusing clonogenic tumor cells with the autograft, producing relapse of the disease in the patient. The use of positive selection techniques to isolate stem cells and thus reduce or eliminate tumor cell contamination has been extensively studied over the past few years. Preliminary clinical results have demonstrated that these procedures deplete 2 to 7 logs of tumor cells and do not impair engraftment. It is too early to assess the ultimate clinical benefit of this strategy. Additional applications of CD34-selection include ex vivo expansion of and gene transfer into hematopoietic progenitor cells and T-cell depletion of allogeneic grafts to reduce the incidence of graft-versus-host disease.
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The goal of our study was to evaluate a rapid noninvasive MR technique for quantification of the pulmonary artery acceleration time (PAT) and other parameters of pulmonary hemodynamics and to correlate with pulmonary artery mean pressure (mPAP). The PAT known as "time-to-peak" out of Doppler echocardiographic measurements normally shows significant inverse correlation with mPAP. With the MR-RACE-Technique (RACE: Real time ACquisition and Evaluation of motion) blood velocity measurements can be obtained with a total acquisition time of a few seconds. The application of this technique to the pulmonary artery has not been reported before. Out of the RACE velocity wave form PAT can be obtained with a temporal resolution of about 15 ms. To explore the relationship between PAT and mPAP, right heart catheterization and MR-RACE measurements were performed in 12 patients with different pulmonary vascular abnormalities. Results of MR-RACE were compared with those of mPAP measured by right heart catheter and showed significant inverse correlation (r = -0.82, p = .0011, n = 12). The ability of MR-RACE to enable measurements of blood flow with profiles may be important for characterizing pulmonary and cardiovascular abnormalities.
Before antibiotics were available, actinomycosis was the most commonly diagnosed "fungal disease" of the lung because of its morphological similarity to true fungi. At that time actinomycosis presented a fairly typical clinical picture of empyema thoracis and sinus tracts in the chest wall. Nowadays it has become a rare infectious disease that is usually caused by the bacterium Actinomyces israelii and is amenable to treatment by most antibiotics available today. The following report describes the case of a 59-year-old man with an uncommon mediastinal actinomycosis that caused an oesophagotracheal fistula. This complication may develop due to the necrotizing inflammatory process that is typical for actinomycosis. With regard to the literature, the clinical manifestations of the disease and diagnostic and therapeutic considerations are discussed.
In the course of preoperative diagnosis, intravasal sonography for tumour imaging was conducted in three patients suffering from central bronchial carcinoma. The catheters of 6.0 or 4.8 French diameter were advanced in each case after pulmonary angiography via the left or right pulmonary artery up to the tumour area. Endosonographic tumour imaging was compared with the findings of the other preoperative diagnostic measures and in two cases with intraoperative and postoperative findings. The vascular walls of the central pulmonary arterial segments showed sonographically no typical three-layer structure. In all cases, however, tumour infiltration was showed up by disappearance of the vascular wall reflexes in the relevant pulmonary artery branches. Visualisation of the mediastinal pulmonary artery segments or of the main stem of the pulmonary artery is difficult with the wire-guided catheters used, since these cannot be stabilised in the centre of the vessel. Development of suitable catheters with low-frequency transducers and greater depth of penetration is imperative especially for the diagnostically important visualisation of the surrounding mediastinal structures.
A 43-year-old man was hospitalized because of extensive bilateral pulmonary tuberculosis. After several weeks of tuberculostatic treatment--at first applied orally, then because of nausea and vomiting parenterally via a central venous catheter--he acutely developed nocturnal dyspnoea and symptoms of shock requiring artificial ventilation. Echocardiography demonstrated dilatation of the right ventricle and a large floating thrombus in the right atrium. During the examination complete displacement of the worm-like thrombus into the pulmonary artery was observed echocardiographically. Despite anticoagulation and immediate operation the patient died 2 days later of protracted shock. The thrombus was found to have been formed in the superior vena cava after placement of the central venous catheter.
An aneurysm of the aorta with aortobronchial fistula formation was seen in a 33 year old patient as a rare cause of recurring hemoptysis. 18 years previously he had undergone surgery of coarctation of the aorta. By means of different imaging methods the diagnosis was established in time and the aneurysm resected, so that the patient survived this mostly fatal incident.
MR blood velocity measurements were performed by the RACE technique in a plane perpendicular to the flow of the pulmonary arteries. MR findings were correlated with those of perfusion scintigraphy, Doppler US and right heart catheter (thermodilution). The ratio of MR blood flow measurements of right and left pulmonary arteries correlated well with the results of perfusion scintigraphy (RPA to LPA) and Doppler. Poor correlation was found when comparing MR blood flow measurements with right heart catheter since absolute flow measurements can be superimposed by neighboring blood vessels in complex anatomic situations.