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Biomedical subjects

R Ewert

Publications and source records attributed to R Ewert.

At least 55 records · Page 3Linked to original sources
PubMed1999

High prevalence of pulmonary diffusion abnormalities without interstitial changes in long-term survivors of liver transplantation.

Abnormalities in lung function are frequent findings in patients with terminal stage chronic liver disease. While spirometric parameters improve early after liver transplantation, a reduction in diffusion capacity has been reported up to 15 months after transplantation. It is unknown to what extent this disturbance in gas exchange occurs among long term survivors after liver transplantation. We assessed lung function in terms of spirometry, and gas exchange as well as pulmonary morphology by high resolution computed tomography (HRCT) in 40 patients 38 months (median, range 20-147 months) after liver transplantation. The prevalence of restrictive or obstructive changes was not different from predicted values. For the whole group of long-term survivors the carbon monoxide transfer coefficient (KCO) was reduced to 71.3 + 12.0% predicted (P < 0.05). HRCT revealed interstitial changes in only 2/40 (5.0%), emphysematous bullae in 2/40 (5.0%) and pleural thickening in 9/40 (22.5%). Diffusion abnormalities are prevalent in the majority of patients after liver transplantation, whereas spirometric abnormalities are absent also in the long term. The high prevalence of impaired gas exchange and the absence of interstitial lesions imply that changes in pulmonary blood vessels are the most likely cause.

Adolescent↗
PubMed1999

[Glycogenosis type IV as a seldom cause of cardiomyopathy - report about a successful heart transplantation].

We report about a 17 year old male patient with a cardiomyopathy secondary to type IV glycogenosis (Andersens disease) and class II immunoglobulin deficiency who underwent cardiac transplantation. The patient first developed symptoms of heart failure at the age of twelve. The histologic diagnosis was cardiomyopathy secondary to glycogenosis. In addition, the patient suffered recurrent pulmonary infections and developed bronchiectases in the left lower lobe. This region was atelectatic since he was eleven. The patient did have two younger brothers who died of congestive heart failure at the age of nine and ten. Neither his parents nor anybody else of his relatives had a history of heart failure or glycogenosis. Since the patient suffered recurrent cardiac decompensations with the need for catecholamines he was accepted for cardiac transplantation although several relative contraindications to transplantation such as cachexia, myopathy, immunglobulin deficiency and bronchiectases had been present. The patient was transplanted successfully. The postoperative weaning from the respirator was markedly prolonged and complicated by pulmonary infection. Furthermore, mobilization was retarded. One year after transplantation, he is in a good condition without pulmonary or systemic infection. Right ventricular endomyocardial biopsies did not show recurrence of glycogenosis in the donor organ.

Adolescent↗
PubMed1999

Pulmonary artery stenosis 5 years after single lung transplantation in primary pulmonary hypertension.

This is a case report about a 56-year-old female patient with primary pulmonary hypertension who underwent single, right lung transplantation. Five years postoperatively she developed signs of right heart failure. History and physical examination suggested pulmonary artery stenosis. Diagnosis was confirmed by pulmonary angiography. Percutaneous placement of a balloon expandable stent normalized pulmonary artery pressure.

Blood Pressure↗
PubMed1999

Measurement of anti-human cytomegalovirus T cell reactivity in transplant recipients and its potential clinical use: a mini-review.

By allowing direct determination of the frequencies of antigen-specific memory T cells in peripheral blood, novel techniques based on flow cytometry provide new diagnostic opportunities in various clinical settings, including organ transplantation. While the importance of the T cell compartment for the anti-human cytomegalovirus (HCMV) immune response is undisputed, efficient monitoring of this response was previously impossible because the conventional methods for measuring CD4+ and CD8+ T cell responses are too time-consuming and cost-intensive. We analyzed how the rapid induction of anti-HCMV CD4+ and CD8+ memory T cells by HCMV viral lysate or HCMV-derived peptides, respectively, followed by a flow-cytometric detection step, may be used to monitor HCMV-specific CD4+ and CD8+ memory T cells in solid-organ recipients. We also discuss a number of preconditions for integrating such testing into the clinical routine.

CD4-Positive T-Lymphocytes↗
PubMed1999

Ventilatory and diffusion abnormalities in long-term survivors after orthotopic heart transplantation.

OBJECTIVE: To investigate the long-term development of pulmonary diffusion abnormalities after orthotopic heart transplantation (oHT). DESIGN: Retrospective analysis of pulmonary function test results of different patient groups at different time intervals after oHT was performed. PATIENTS: This investigation included 642 patients who had undergone oHT for chronic heart failure. Patients were grouped according to the time elapsed after transplantation (group 1: n = 164; age, 47 +/- 14 years; days after oHT, 324 +/- 101; group 2: n = 100; age, 48 +/- 15 years; days after oHT, 723 +/- 104; group 3: n = 106; age, 52 +/- 12 years; days after oHT, 1,092 +/- 98; group 4: n = 84; age, 51 +/- 13 years; days after oHT, 1,442 +/- 99; group 5: n = 61; age, 50 +/- 14 years; days after oHT, 1,819 +/- 105; group 6: n = 101; age, 53 +/- 12 years; days after oHT, 2,463 +/- 303; and group 7: n = 26; age, 54 +/- 14 years; days after oHT, 3,478 +/- 246). In 56 (group 8) of the 642 patients, follow-up measurements were performed with tests before and at two time points after oHT (6.5 +/- 1.7 and 12.5 +/- 9.3 months). RESULTS: Of all patients, 39% showed restrictive and obstructive abnormalities with no differences between the groups. No significant differences in lung transfer factor for carbon monoxide (DLCO) were observed (61.2 vs 63.7 vs 65.5 vs 65.6 vs 64.5 vs 65.7 vs 67.6% predicted). Differences in transfer coefficient for carbon monoxide (Kco) were significant between group 1 and 4 (58.7 vs 64.1% predicted), and group 1 and 6 (58.7 vs 63.4% predicted). No differences occurred in the rate with which patients exhibited pathologic abnormalities for DLCO and KCO. After oHT, a marked reduction in diffusion capacity occurred in group 8. On follow-up, these measurements were only slightly restored in terms of the predicted DLCO percentage. No such improvement was observed in KCO or in the rate of pathologic changes for both DLCO and KCO. We conclude, therefore, that the impairment of diffusion does not improve even after a significant period has passed after the oHT. Whether this has any effect on symptoms and/or the prognosis for these patients is extremely unclear.

Carbon Monoxide↗
PubMed1999

Motion artifacts in cardiac CT. The Novacor left ventricular assist device and its implications for clinical imaging.

PURPOSE: Cardiovascular applications of CT are primarily limited by temporal resolution of the scanner. Recent development in scanner technology has greatly increased temporal resolution. We here describe a standardized method of assessing temporal properties of various CT techniques. MATERIAL AND METHODS: The Novacor left ventricular assist device was mounted in a water-filled circulation phantom and scanned at different pump rates with a spiral CT unit and an electron beam unit. We also evaluated the use of ECG-triggered subsecond scanning on a spiral CT unit. RESULTS: Using the fastest conventional scanning protocol, severe motion artifacts occurred. These artifacts could not be reproduced from image to image, even if the pump rate was adjusted to scan rate (l/s). Electron beam tomography (EBT) reproducibly yielded few artifacts at 100 ms and practically no artifacts at 50 ms scanning time. Even without ECG-triggering, pump motion could be reproduced as a cine-cycle. With the ECG-triggered partial scanning CT technique, limited motion artifacts could be reproduced during diastole at a heart rate of 70-80 beats/min. CONCLUSION: The Novacor ventricular assist device may serve as a benchmark test in the evaluation of new scanning techniques for cardiovascular CT. While EBT presently remains the only CT technique to freeze cardiac motion throughout its cycle, ECG-triggered subsecond scans may, under certain conditions, capture cardiac anatomy in diastole.

Artifacts↗
PubMed1998

Intravenous injection of India ink with suicidal intent.

We describe the case of a 33-year-old man who injected 4 ml of India ink into one of the median cubital veins with suicidal intent. He was hospitalized in good general condition 10 h after the injection. Abnormal laboratory test results were a leukocytosis, an oximetrically determined methemoglobin level of 36.9% (normal range: 1.5%) and a free hemoglobin level of 74 mumol/L (normal range: < 25 mumol/L). Toxicological examination showed the presence of nitrobenzene in blood and urine. Intravenous administration of vitamin C and tolonium chloride plus forced diuresis led to an improvement in cyanosis and a fall in the methemoglobin concentration. Repeated increase in the concentration of aminobenzene were successfully treated by hemodialysis with a high-flux dialyzer.

Adult↗
PubMed1997

Pentoxifylline promotes replication of human cytomegalovirus in vivo and in vitro.

OKT3 monoclonal antibody (MoAb) therapy is well established in the prevention and therapy of acute rejection in transplant patients. Unfortunately, this therapy is associated with several short-term (cytokine release syndrome) and long-term (infections, EBV-related lymphoma) side effects. Recently, we were able to demonstrate an association between the TNF alpha release following the first OKT3 MoAb infusions and the appearance of human cytomegalovirus (HCMV) reactivation several days later. In order to prevent this TNF alpha associated HCMV reactivation patients were additionally treated with pentoxifylline (PTX), a methylxanthine derivative that has been shown to suppress TNF alpha induction. Although the TNF alpha peak plasma level following OKT3 MoAb treatment was markedly reduced, the incidence of HCMV reactivation and HCMV disease was not influenced. In transient transfection experiments using HCMV immediate early enhancer/promoter CAT reporter gene constructs PTX enhanced the promoter activity independently from TNF alpha in premonocytic cells. Furthermore, PTX acted synergistically with TNF alpha. In virus-infected human embryonal lung fibroblasts HCMV replication was triggered in the presence of both PTX and TNF alpha, while either substance alone had only marginal effects. The stimulatory effect of PTX on the immediate early (IE) enhancer/promoter was mediated via CREB/ ATF, a eukaryotic transcription factor that binds to the 19 bp sequence motif in the enhancer region, while TNF alpha stimulation was mediated by activation of the transcription factor NF-kappaB and its binding to the 18 bp sequence motif in the enhancer. These data suggest a potential side effect of cAMP-elevating drugs such as PTX.

Acute Disease↗
PubMed1997

Colour-coded duplex sonography in the diagnostic assessment of vascular complications after kidney transplantation in children.

BACKGROUND: Vascular complications are a major cause of dysfunction or transplant loss in children. Arterial or venous occlusion, transplant renal artery stenosis (TRAS) and some arteriovenous (AV) fistula require rapid detection and prompt intervention. The present study was performed to determine the accuracy of colour Doppler sonography (CDS) in the early and late phase after renal transplantation and to correlate the results with angiographic and intraoperative findings. OBJECTIVE: CDS is the preferred imaging modality with a high diagnostic accuracy for follow-up of renal transplantation in children. The indication for angiography should be established on the basis of the CDS diagnosis. MATERIALS AND METHODS: In 87 children (mean age 10.9 years, range 2-17), 423 CDS examinations were performed after renal transplantation. Angiography was performed in 17 cases; surgery was necessary in 16 patients. RESULTS: CDS correctly identified 8/8 arterial or venous occlusions and 7/7 TRAS. The only false positive diagnosis of TRAS was due to misinterpretation of an iliac artery stenosis. Six AV fistulae were diagnosed by CDS. The overall positive predictive value of CDS was 94 % in this study. CONCLUSION: CDS is a noninvasive, non-radiation producing imaging modality with a high diagnostic accuracy. It is the method of choice in the assessment of vascular complications after renal transplantation in children.

Adolescent↗
PubMed1997

[Histologic specimen collection in pulmonary hypertension using percutaneous, transvascular biopsy--animal experiment and initial clinical data].

Pulmonary hypertension is a severe multietiological disease largely resistant to treatment. Biopsy is often necessary to establish differential diagnosis. In pulmonary hypertension transbronchial pulmonary biopsy is contraindicated and open lung biopsy is the method of choice. In our paper we report about experimental results in animals and first clinical data on a new biopsy technique (percutaneous transluminal biopsy, PTB) providing access to histology in pulmonary hypertension without the need of surgery. In a subset of animals pulmonary hypertension was produced experimentally. In addition, we carried out the PTB in patients with bronchial carcinoma. Our preliminary results demonstrate that sufficient material could be gained for the histologic evaluation of pulmonary parenchyma and in pulmonary vessels. No complications have been noted so far.

Animals↗
PubMed1997

[Acute graft versus host disease (GvHD) after heart-lung transplantation].

We report on a 28 year old woman with congenital ventricle-septum defect and Eisenmenger-reaction who developed acute GvHD on 10th postoperative day after successful heart-lung transplantation. The patient died on the 34th postoperative day of dissociated brain death after intracerebral bleeding.

Acute Disease↗
PubMed1997

Temporary tracheobronchial stenting in malignant stenoses.

Endobronchial stent implantation has been successfully employed in malignant stenoses. The aim of this prospective study was to investigate the temporary use of tracheobronchial stents combined with tumour-specific therapy. All patients received stents for primary palliation of dyspnoea followed by radio- or chemotherapy with the aim of stent removal after reduction of the stenosis. In 22 patients suffering from severe malignant strictures, 34 endobronchial stents (29 Strecker-, 3 Dumon-, 1 Orlowski-, 1 Dynamic-Y-stents) were implanted (in 9 patients, 2 stents were necessary). Patients were treated by irradiation (n = 18) or chemotherapy (n = 4) after stent implantation. Significant improvement of dyspnoea (P < 0.001) and partial oxygen pressure (P < 0.01) was observed. In 11 out of 22 cases (50%), the stents could be removed after successful tumour-specific therapy which led to reduction of stenosis after a mean interval of 31.7 (6-104) days (temporary stenting). During the period of tumour-specific therapy, 9 patients died after a mean interval of 132 (13-347) days (definite stenting). In two cases, stents had to be removed after stent compression, stent dislocation and severe cough. The results suggest that temporary stenting, characterised by subsequent successful tumour-specific therapy, is a new valuable therapeutic strategy. It can "bridge the gap" before tumour-specific therapy can take effect. If tumour-specific therapy is ineffective, definite stenting is the palliative method of choice in severe dyspnoea in bronchial carcinoma.

Adult↗
PubMed1997

Computed tomography-guided transtracheal needle aspiration of paratracheal lymphadenopathy in endoscopically normal patients.

RATIONALE AND OBJECTIVES: The authors investigated the diagnostic value of computed tomography-guided bronchoscopic transtracheal needle biopsy of paratracheal lymphadenopathy without any endoscopical signs of stenosis or protrusion. METHODS: Twenty consecutive patients with an age of 22 to 76 years underwent fiberoptic bronchoscopy with transtracheal needle biopsy under computed tomography guidance of paratracheal lymphadenopathies (diameter between 10 to 19 mm). Computed tomography fluoroscopy as a special low-dose computed tomography technique was used in the region of interest. The results of needle aspirates (cytologic examination) were verified by surgical interventions (n = 4), mediastinoscopy (n = 9), percutaneous needle biopsy (n = 1), or clinical/radiologic follow-up (n = 10). RESULTS: All patients were without endoscopic signs of lymphadenopathy or tumor. Sufficient material of lymphatic tissue for cytologic assessment was obtained in 23 out of 24 patients (96%). In 5 of 10 patients with malignant diseases and 13 of 14 patients with benign enlarged lymph nodes, the lymph nodes were demonstrated exactly by transtracheal needle biopsy. There were no bleeding complications. CONCLUSIONS: Computed tomography-guided bronchoscopic needle biopsy of paratracheal lymphadenopathy is a low-risk procedure. If malignant cells can be demonstrated with these technique, other more invasive procedures (surgery, mediastinoscopy) can be avoided. The numerous false-negative results (5 of 10) suggest, that the cytologic evidence of benign cells is without any diagnostic value in cases of paratracheal lymphadenopathy.

Adult↗
PubMed1997

[Stent implantation in severe tracheal and bronchial compression caused by aortic aneurysm].

A space-occupying growth in the left upper area of the lung was confirmed in a female patient of 75 years of age suffering from progressive cough and intermittent dyspnoea. Fibre bronchoscopy revealed distal stenosis of the trachea, the total findings being interpreted as pointing to the existence of a mediastinal tumour. A few hours after bronchoscopy the patient suffered from respiratory insufficiency, and the patient was referred to us with continuously increasing positive airway pressure breathing, for further clarification. We performed as an emergency measure bilaterally an endobronchial stent implantation. After airway pressure breathing had returned to normal, and subsequent extubation, compression of a stent occurred followed by renewed compulsory breathing. Ventilation could be optimised by an additional implantation of a stent. Cause of the compression was later identified as a monstrous aneurysm of the thoracic and abdominal aorta. During further conservative treatment there was a progressive bronchopneumonia and renal insufficiency requiring dialysis. The patient died on the 8th day after stent implantation. Autopsy showed that the stents were properly in position.

Aged↗
PubMed1996

Multiple fistulas and tracheobronchial stenoses require extensive stenting of the central airways and esophagus in squamous-cell carcinoma.

We report here on two cases of double airway and esophageal stenting in patients with multiple esophagotracheal fistulas and stenoses of the airways and esophagus due to squamous-cell carcinoma. Dumon stents and a Strecker device were used for tracheobronchial stenting. Covered Gianturco Z-stents were implanted into the esophagus. In one case, extrinsic compression of the trachea and tumor progression required recanalization by Nd:YAG laser. Clinical improvement led to discharge of the patients within two weeks after the procedure. The results show that simultaneous implantation of stents in the central airways and covered Gianturco Z-stents in the esophagus is an effective therapeutic strategy in patients with tracheal and esophageal obstructions and esophagorespiratory fistulas. Further systematic studies evaluating double stenting are warranted.

Aged↗