Biomedical subjects

K Engelmann

Publications and source records attributed to K Engelmann.

At least 37 records · Page 2Linked to original sources

PubMed2001

[Visualization techniques in multislice CT-coronary angiography of the heart. Correlations of axial, multiplanar, three-dimensional and virtual endoscopic imaging with the invasive diagnosis].

OBJECTIVE: To evaluate the performance of 4 different visualization techniques for multislice CT datasets from the coronary arteries in comparison to coronary angiography. MATERIAL AND METHODS: 42 patients were examined prospectively using both multislice CT and angiocardiography. All CT scans were performed at collimation 4 x 1 mm, pitch 1.5 and a rotation time of 500 msec. Using retrospective ecg-gating, image reconstruction parameters were 1.25 mm slice thickness, 0.5 mm increment and kernel B30. Each patient's CT dataset subsequently was explored using axial, multiplanar, three-dimensional, and virtual endoscopic visualization modes. RESULTS: Axial scans showed the highest sensitivity in the evaluation of stenoses (66.7%), followed by virtual endoscopy (55.9%), multiplanar (48.6%), and three-dimensional reformations (33.3%). With regard to the detection of atherosclerotic plaques, axial scans (71.2%), three-dimensional reformations (70.1%), and virtual endoscopy (69.1%) displayed comparable sensitivities, whereas multiplanar reformations showed distinctly lower results (55.6%). On combining the techniques a sensitivity of 74.2% for the detection of atherosclerotic plaques, of 72.0% for the identification of high-grade stenoses, respectively, was obtained. The specificity of all four visualization modes amounted to 91.9% and above. Best results have been obtained within the RIVA (sensitivity 85.2%). CONCLUSION: For the detection of atheromatous changes CT angiocardiography does not achieve a sensitivity as high as angiocardiography and is restricted to the three major branches. At heart rates below 60 bpm axial scans showed the best correlation in the quantification and classification of atherosclerotic plaques.

Aged↗

PubMed2001

[Early clinical results with mycophenolate mofetil in immunosuppressive therapy of ocular pemphigoid].

BACKGROUND: Ocular cicatrical pemphigoid can lead to severe structural damage or loss of vision at worst. Longterm therapy with dapsone or systemic immunosuppressive therapy, e.g. with cyclophosphamide is often inevitable. Immunosuppression may cause severe side effects in some patients. PATIENTS AND METHODS: Data are presented on 5 patients with ocular cicatrical pemphigoid who were treated with mycophenolate mofetil 2 g daily. Criterion of effectiveness was the clinical course of the condition defined as nonprogression of the morphologic alterations. Patients were initially examined and interviewed routinely every four weeks for the first four months, then every eight weeks. Patients were asked about side effects and underwent monthly blood checks. RESULTS: All patients were followed for at least 12 months. Mycophenolate mofetil proved to be effective with respect to the clinical course in 9 out of 10 eyes. All patients showed regression of inflammatory conjunctival alteration and improvement of their complaints. In one eye the inflammatory process restarted after surgery due to excessive symblephara had been performed. Gastrointestinal side effects were reported in the initial phase, e.g. lack of appetite, nausea and mild diarrhoea. CONCLUSIONS: Mycophenolate mofetil proved to be an effective immunosuppressant for the treatment of ocular cicatrical pemphigoid. Namely side effects were less severe and frequent compared to those known from other currently administered immunosuppressants. Longterm results and larger case numbers are needed to sustain these early results.

Adult↗

PubMed2001

[Percutaneous laser ablation of malignant liver tumors].

PURPOSE: To present the technical data, methods and results of percutaneous laser ablation of malignant tumors. PATIENTS AND METHODS: In the period from June 1993 to April 2000 a collective of 600 patients with malignant liver tumors and liver metastases from different primary tumors were treated via MR-guided LITT. After sonographically or CT-guided puncture MR-compatible laser catheters were positioned. The tumor destruction was visualized via MR-thermometry. The checkup and the therapy accomplishment ensued in the course of an ambulant therapy concept. RESULTS: In the course of a local accomplished LITT of liver metastases and malignant liver tumors a local tumor control rate of 97.8 % was achieved. The complication rate was extremely low with a value of 2.2 % (1 441 treatments). The lethality rate was 0.1 %. The mean survival time referring to the whole patient collective was 47.7 months, in the case of liver metastases from a colorectal cancer a value of 46.8 months was achieved. CONCLUSION: MR-guided LITT is a local effective therapy with low morbidity in malignant liver tumors with a maximum quantity of 5 and a size of </= 5 cm.

Adult↗

PubMed2001

[Renal enhancement and excretion of the hepatobiliary contrast agent Gd-EOB-DTPA].

PURPOSE: To evaluate the clinical value of the renal clearance using MR imaging with different doses of gadolinium ethoxybenzyl-DTPA (Gd-EOB-DTPA) in comparison to gadolinium DTPA (Gd-DTPA). MATERIAL AND METHODS: In a double-blind and randomized clinical phase II study. MR imaging at 1.5 T was performed in 61 patients with five different doses of Gd-EOB-DTPA (3, 6, 12.5, 25 and 50 micromol/kg b. w. as a bolus injection). The study protocol comprised T(1)- and T(2)-weighted spin-echo magnetic resonance and two-dimensional fast low-angle shot imaging before and at increasing intervals for up to 45 min after injection of Gd-EOB-DTPA. These images were compared with Gd-DTPA-enhanced imaging (0.1 mmol/kg b. w. as a bolus injection). RESULTS: After bolus injection of the hepatobiliary MR contrast agent Gd-EOB-DTPA a renal elimination was observed. Immediately after the injection of Gd-EOB-DTPA until the eighth minute a corticomedullary enhancement of the kidney was conspicuous. After the fourth minute a contrast enhancement could be seen in the renal pelvis. The best enhancement was noted after 20 minutes in the FLASH GRE and T(1)-weighted images with good pelvicaliceal contrast. After 45 minutes an outflow of Gd-EOB-DTPA into the ureter could be observed. CONCLUSION: In addition to the hepatobiliary secretion Gd-EOB-DTPA appears useful for the evaluation of renal structures and renal function on account of the renal excretion without diuretic preparation of the patients.

Adult↗

PubMed2001

Effect of three different media on serum free culture of donor corneas and isolated human corneal endothelial cells.

BACKGROUND: Removal of bovine serum from organ culture medium is necessary because of the variability in serum composition and the potential risk of infection. Two specific endothelial cell media (F99 and Endothelial-SFM) were compared with the routinely used medium MEM for their use in serum free cultivation of human corneal endothelial cells (HCEC) and donor corneas. METHODS: HCEC were incubated in three test media with or without increasing serum content and a growth assay was performed. Seven pairs of donor corneas were cultured in each of three media for 3 weeks, one cornea with serum supplementation and one without. Endothelial cell density was determined once each week. Trypan blue staining of the endothelium and vital staining of keratocytes was performed after 3 weeks. RESULTS: All three media promoted proliferation of cultured HCEC when supplemented with serum. Endothelial cell density of donor corneas was comparable after 3 weeks of cultivation in the different media. Only corneas cultured in medium MEM without serum exhibited a higher endothelial cell loss. Trypan blue staining of the endothelium after cultivation revealed the lowest number of damaged cells on corneas cultured in the medium Endothelial-SFM. The highest densities of keratocytes were found in corneas cultured in Endothelial-SFM and the lowest densities occurred after culture in MEM. CONCLUSION: After incubation in Endothelial-SFM even under serum free conditions corneas were found to be of higher quality with respect to endothelial cell survival, cell membrane integrity, and keratocyte density. This medium may replace MEM, which is routinely used in European eye banks but requires supplementation with serum.

Aged↗

PubMed2001

Evaluation of potential organ culture media for eye banking using human donor corneas.

AIM: To evaluate the ability of different commercially available cell culture solutions to preserve human donor corneas during 3 weeks of "closed system" organ culture at physiological temperature. This screening was performed in an attempt to establish a rational basis for the development of a serum-free organ culture medium for eye banking. METHODS: 72 normal human donor corneas were organ cultured for 21 days at 31 degrees C in eight different test media (nine corneas in each group). The basic culture solutions included: minimal essential medium (MEM), MEM with stabilised L-glutamine, M199, DIF-1000, SFM, F99, and F99 with ascorbic acid, insulin, bFGF, transferrin, selenium, and lipids (termed F99-Sr). All media were supplemented with 2% fetal calf serum (FCS), except for MEM, which was also studied at 8% FCS. The evaluation parameters included: (1) the endothelial cell loss as evaluated using trypan blue staining; (2) the ability of keratocytes and endothelial cells to incorporate tritiated uridine into RNA as evaluated using autoradiography and digital image analysis; (3) the leakage of immunogenic keratan sulphate as assessed using ELISA; and (4) changes in storage medium pH, glucose, and lactate content. RESULTS: SFM induced the lowest endothelial cell loss of 14% (SD 2%) and the highest RNA synthesis rates of all test solutions supplemented with 2% FCS. Corneas stored in SFM also showed the least leakage of keratan sulphate and the highest glucose consumption and lactate production. In five media (MEM with 2% FCS, MEM with stabilised L-glutamine, M199, F99, and F99-Sr), comparable and intermediate potentials for organ culture were observed with endothelial cell loss of 16-19%. By contrast, 29% (4%) of the endothelium was lost after storage in DIF-1000. Interestingly, the use of 8% FCS (in MEM) had a marked protective effect on the endothelium, which showed the highest RNA synthetic activity combined with a cell loss of only 11% (4%), compared with 19% (6%) at 2% FCS (p<0.05). CONCLUSION: Among the present test solutions, SFM appears to be the most prominent candidate for a new corneal organ culture medium and should be further tested and possibly refined to effectively substitute serum addition.

Adult↗

PubMed2000

Recent developments in cornea transplantation (1997-1999).

Between 1997 and 1999 a steady increase in cornea donations was achieved, but the number of transplantations remained stable because many grafts did not pass quality control. Intermediate organ culture of entire bulbi was examined as a possible solution to reduce post-mortem times and increase suitability for transplantation.

Corneal Transplantation↗

PubMed2000

[Endophthalmitis after cataract surgery: predisposing factors, infectious agents and therapy].

BACKGROUND: Infectious exogenous endophthalmitis is a serious complication after cataract surgery. Despite modern pharmacological and surgical methods, its treatment is still difficult. PATIENTS AND METHODS: In a retrospective study the records of all patients treated for endophthalmitis following cataract extraction at the Department of Ophthalmology of the University Hospital in Hamburg between January 1989 and December 1997 were assessed. RESULTS: Of 36 patients treated for endophthalmitis, 29 (80.6%) had been referred. In 14 (38.9%) of these 29 patients endophthalmitis had occurred after outpatient cataract surgery. Seven patients (19.4%) had been treated as inpatients at the University Eye Hospital Eppendorf. Vitrectomy was performed in 80.6% of the cases. An infectious agent was isolated from 50% of diagnostic probes. The most common organism isolated were coagulase-negative staphylococci (4 cases). Predisposing factors for the development of endophthalmitis were diabetes (27.8%), intraoperative loss of vitreous (19.4%), application of systemic steroids (13.9%) and wound dehiscence (11.1%). Of 27 patients (75%) followed up, 16 (59.3%) had a final visual acuity of 20/400 or better (mean 20/40). An enucleation had to be performed in 4 patients (13.8%). CONCLUSION: In this study, approximately 60% of patients with endophthalmitis following cataract extraction had their globes preserved and a good visual outcome after appropriate surgical interventions.

Adrenal Cortex Hormones↗

PubMed2000

[Prolonged wound healing after perforating keratoplasty. CPAP hyperbaric ventilators for sleep apnea as a risk factor].

Nasal hyperbaric respiration devices used at night to counteract sleep apnea may represent a concealed cause of delayed superficial wound healing following perforating keratoplasty. We report the cases of two patients whose respirators produced a continuous flow of pressurized air (nCPAP) onto the operated eyes, leading to conjunctival hyperemia, recurrent corneal erosion, infiltration of the puncture track and the cornea, and superficial punctate keratopathy. Microbiological investigation revealed no clearly identifiable pathogens. Healing improved consistently only after the pressurized air system had been modified so that no air escaped from the nostrils and the patients had been instructed in disinfection of the moisturizing system.

Adult↗

PubMed2000

Effect of perfluorodecalin on human retinal pigment epithelium and human corneal endothelium in vitro.

BACKGROUND: Perfluorocarbon liquids are useful intraoperative tools in complicated vitreoretinal surgery. They are usually removed at the end of the procedure, but small amounts may remain in the eye. Recently, contradictory results have been reported on the damage in association with residual perfluorocarbon liquids in the eye. This study examined the effects of perfluorodecalin on human retinal pigment epithelium and corneal endothelium in vitro. METHODS: Vitality and proliferative capacity of cell cultures were measured after incubation with perfluorodecalin. Vitality of cell cultures were measured using the Life-Dead assay. Cell proliferation was determined by measuring incorporation of 5-bromo-2'-deoxyuridine into cellular DNA. Furthermore, endothelium of organ-cultured human corneas was examined after incubation with perfluorodecalin by photodocumentation. RESULTS: Both cell types showed less extinctions in the Life-Dead assay after incubation with perfluorodecalin. After removing perfluorodecalin from the cultures, cells showed the same capacity of proliferation as the control cells. Compared to control corneas, perfluorodecalin induced a decrease in endothelial cell density. In four corneas, endothelial cell necrosis was observed. CONCLUSION: Decreasing extinctions in the Life-Dead assay after incubation with perfluorodecalin can be interpreted as showing a decreasing amount of vital cells. Because cell proliferation showed no significant changes the results suggest that perfluorodecalin may not be directly toxic to cells in vitro. It may exert an indirect or mechanical effect on cell function by impeding the normal metabolic exchange between endothelium and medium. Based on these results perfluorodecalin should be completely removed after operation.

Cell Count↗

PubMed2000

Immortalization of human corneal endothelial cells using electroporation protocol optimized for human corneal endothelial and human retinal pigment epithelial cells.

PURPOSE: In this study we established a protocol for transfection of human corneal endothelial and human retinal pigment epithelial cells. This protocol was used for immortalization of human corneal endothelial cells. METHODS: Transfection was performed by means of electroporation. For immortalization a plasmid encoding large and small SV40 T-antigen was used. RESULTS: The established electroporation protocol was suitable for both cell types. This protocol was used for transfection of human corneal endothelial cells with a plasmid containing the early region of SV40. The transfected cultures exhibited an increased life-span before they entered crisis. One culture recovered from crisis and was cultivated for 300 population doublings. The cells exhibited an in vivo-like morphology usually lost during cell culture. CONCLUSIONS: We describe for the first time a culture of SV40 transfected human corneal endothelial cells which recovered from crisis and can therefore be regarded as immortalized.

Adult↗

PubMed2000

[Percutaneous interstitial thermotherapy of malignant liver tumors].

PURPOSE: Description of local ablative techniques such as laser-induced thermotherapy (LITT) and radiofrequency ablation in the percutaneous interstitial thermotherapy for malignant liver tumors. PATIENTS AND METHODS: MR-guided LITT is currently performed by means of implantable percutaneous catheter systems. CT is used to control the insertion of the catheter. Irrigated administration systems are available both for LITT and for radiofrequency therapy. RESULTS: At present LITT enables a local tumor control of 97.2% for localized liver metastases without extrahepatic spreading patterns. In a group of 381 patients the average survival times were 45.7 months for patients with liver metastasis, 42.7 months for those with colorectal liver metastases, and 32 months for HCC tumors. The data for radiofrequency ablation confirm the high value for tumor control of hepatocellular carcinomas with poorer results for liver metastases. CONCLUSIONS: Percutaneous, MR-guided LITT permits good tumor control of liver metastases smaller than 5 cm and less than 5 in number. For HCC, at present percutaneous injection of alcohol, radiofrequency ablation, and LITT are equally effective.

Breast Neoplasms↗

PubMed2000

[Percutaneous transvenous recovery of foreign bodies using a self-made wire loop].

AIM: Several techniques exist to retrieve catheter and guide wire fragments. In this report we summarize our cost-saving method. MATERIALS AND METHODS: A 7-8F guiding catheter and a self-made loop consisting of a 260 cm/0.035 in. Terumowire was used. RESULTS: 45 of 48 fragments were retrieved completely using this method. For the three remaining fragments (all pacemaker electrodes), retrieval was attempted with a "Goose-Neck" loop, two of them failed. The procedure was well tolerated, there were no severe complications. CONCLUSION: Usually venous foreign bodies can be retrieved completely by this cost-saving method, the use of expensive industrial loops or baskets can be avoided.

Angiography↗

PubMed2000

[CT-guided percutaneous intratumoral chemotherapy with a novel cisplatin/epinephrine injectable gel for the treatment of inoperable malignant liver tumors].

PURPOSE: To evaluate prospectively the volumetric changes of tumor and necrosis in unresectable malignant liver tumors and the clinical aspects after CT-guided direct intratumoral administration of a novel cisplatin/epinephrine injectable gel in a clinical phase II study. PATIENTS AND METHODS: 8 patients with 17 colorectal liver metastases with a mean volume of 42 ml were treated with a mean of 5.1 injections and 8 patients with 11 HCC nodules (mean volume of 22.1 ml) with a mean of 3.25 treatments with CT-guided local administration of a novel cisplatin/epinephrine gel. This method of administration provides a higher local and lower systemic drug concentration. Volumes of tumor and necrosis prior to and after treatment were measured by computer-generated volumetric analysis. RESULTS: Contrast-enhanced studies verified pretherapeutic tumor necrosis with a value of 12.6% in the metastases and 0.6% in the HCC nodules. Intratumoral drug administration resulted in a necrotic volume of 110% in metastases and 128% in HCC versus the mean initial tumor volume, at least 4 treatments resulted in 122% necrosis in metastases and 130% in HCC. Local therapy control rate for the follow-up to 6 months was 38% and 83.3% for the group of metastases and HCC, respectively. CONCLUSIONS: Direct intratumoral injection of a novel cisplatin/epinephrine injectable gel results in an induction of a relevant necrosis in malignant liver tumors, with a substantially higher local therapy control rate for HCC compared to colorectal metastases.

Adult↗

PubMed1999

Morphological and functional analysis of immortalized human corneal endothelial cells after transplantation.

Approximately 50% of donor corneas are unsuitable for keratoplasty due to an unacceptably low endothelial cell count. One way of overcoming this problem and minimizing wastage of donor corneas may be to transplant cultured human corneal endothelial cells onto these. In this study, we examined the morphological characteristics and functional attributes of endothelial layers formed after the transplantation of immortalized cells in vitro. Cultured human corneal endothelial cells, immortalized by transfection with a plasmid encoding SV40 T-antigen, were seeded onto human corneas denuded of their own endothelium. Seven days after transplantation the newly established monolayers were examined by light, confocal and scanning electron microscopy. Endothelial pump function was gauged by monitoring changes in corneal thickness during perfusion of the endothelial face. The endothelia formed from transplanted immortalized cells had a cobblestone-like appearance, being composed of polygonal units joined by junctional complexes. The stromal hydration state of corneas bearing such endothelial layers could be controlled during perfusion. This was an active process achieved via the Na(+)/K(+)-ATPase-dependent endothelial pump, as demonstrated by inhibiting the enzyme with ouabain. Transplantation of immortalized human corneal endothelial cells onto recipient corneas led to the establishment of new monolayers which had the morphology of the native ones in organ-cultured corneas. This model provides us with a means of studying the formation and function of corneal endothelial layers in vitro.

Aged↗

PubMed1999

[Therapeutic options in non-resectable liver metastases. Percutaneous radiological interventions].

In patients with irresectable liver metastases the following spectrum of oncological concepts is in use. Percutaneous interventional methods allows for an optimized local control rate in strictly intrahepatic disease. Regional short-term time chemotherapy and transarterial chemoembolization (TACE) belong to regional methods. As local ablative methods, intratumoral drug application, endotumoral chemotherapy and alcohol instillation can be used. The most promising thermotherapeutic strategies are radiofrequency and laser-induced thermotherapy (LITT). In a prospective study 278 patients suffering from liver metastases were treated with MR-guided LITT and exact data for the local control rate and survival rate were evaluated. The overall cumulative survival rate (Kaplan-Meier) of patients with liver metastases was 40.8 months (median: 40.97 months, 95% confidence interval 36.3-45.2).

Adult↗

PubMed1999

[Interventional MR-guided laser induced thermotherapy in oncologic indications. Status and prospects].

MR-guided LITT (laser-induced thermotherapy) is currently being evaluated for its effectiveness in clinical oncology. MR-guided LITT is defined as a minimally invasive technology based on the effects of the applied Nd-YAG laser on tumorous tissue. Due to specific characteristics of the laser-induced coagulative effect, online monitoring via MR thermometry is possible and extremely precise. In a period of 6 years 335 patients suffering from malignant soft tissue tumors were prospectively treated via MR-guided LITT. We evaluated the local tumor control rate, the rate of complications and the survival data from the clinical and MRI follow-up. Our results prove that MR-guided LITT results in a extremely low rate of side effects and an effective tumor control rate higher than 95%, depending on the size of the lesion. It is concluded that this therapeutic concept is of clinical value for patients with primary and secondary liver cancer, malignant lymph node involvement, abdominal recurrent tumors and tumors of the head and neck.

Adult↗

PubMed1999

Liver metastases: interventional therapeutic techniques and results, state of the art.

The liver is the most common site of metastatic tumour deposits. Hepatic metastases are the major cause of morbidity and mortality in patients with gastrointestinal carcinomas and other malignant tumours. The rationale and results for interventional therapeutic techniques in the treatment of liver metastases are presented. For the treatment of patients with irresectable liver metastases, alternative local ablative therapeutic modalities have been developed. Technique and results of local interventional therapies are presented such as microwave-, radiofrequency (RF)- and ultrasound ablation, and laser-induced interstitial therapy (LITT), cryotherapy and local drug administration such as alcohol injection, endotumoral chemotherapy and regional chemoembolisation. In addition to cryotherapy, all ablative techniques can be performed percutaneously with low morbidity and mortality. Cryotherapy is an effective and precise technique for inducing tumour necrosis, but it is currently performed via laparotomy. Percutaneous local alcohol injection results in an inhomogeneous distribution in liver metastases with unreliable control rates. Local chemotherapeutic drug instillation and regional chemoembolisation produces relevant but non-reproducible lesions. Laser-induced interstitial thermotherapy (LITT) performed under MRI guidance results in precise and reproducible areas of induced necrosis with a local control of 94%, and with an improved survival rate. Interventional therapeutic techniques of liver metastases do result in a remarkable local tumour control rate with improved survival results.

Antineoplastic Agents↗