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Biomedical subjects

J Bier

Publications and source records attributed to J Bier.

At least 19 recordsLinked to original sources
PubMed2001

Intraoperative computed tomography with the mobile CT Tomoscan M during surgical treatment of orbital fractures.

Up to now it has only been possible to monitor the alignment of orbital floor fractures postoperatively with a computed tomography (CT) examination with coronal sectioning. If this showed an incorrect positioning, renewed surgery and anaesthetics were often required. The purpose of this study was the implementation and definition of the spectrum of indications for intraoperative CT examinations while keeping patient radiation exposure to a minimum. Thirty-two orbital fracture cases were examined pre- and intraoperatively using the mobile computer tomograph Tomoscan M in coronal sectioning. In this patient collective, 12 cases showed an isolated orbital floor fracture and twenty cases an orbital floor fracture associated with a zygomatic fracture. The technical prerequisite for these examinations was the construction of a suitable radiolucent operating table which permitted coronal sections to be made with the CT-Gantry tilted. The authors aimed to reduce radiation exposure by optimizing the technical setting parameters and closely defining the scan region for the operator. In three of 32 cases there were no surgical indications following clinical and preoperative CT examination. In three of the 20 cases with associated zygomatic fracture a closed reduction with a reduction hook was carried out, and no revision was necessary after the intraoperative CT examination. In 26 cases an open reduction was carried out. Of these open reduced fractures, four had to be revised after intraoperative CT monitoring; one of the isolated orbital floor fractures and three of those associated with a zygomatic fracture. Intraoperative CT monitoring of orbital floor fractures is considered a useful surgical aid. Its advantages are immediate monitoring of the surgical reduction, the presence of the surgeon during scanning enabling him to determine directly the relevant sections to scan, and the resulting radiation exposure.

Adult↗
PubMed2001

Recombinant human erythropoietin in the treatment of head and neck tumour anaemia.

At the time of first diagnosis, patients with squamous cell carcinoma in the head and neck are often in the advanced stage of their disease, therefore surgery is not a viable option for treatment. These patients also present frequently a high grade of anaemia as a result of either the malignant process itself or of the following therapy. The incidence of anaemia and the need for transfusion depends on several factors, such as the type and intensity of radiotherapy and radiochemotherapy. Multimode therapeutic concepts such as radio-chemotherapy are being applied with increasing frequency, resulting in an ever increasing need for transfusion with great effects on the patient's quality of life. Even more important to tumour patients is the role of the haemaglobin (Hb) value as a prognostic factor for survival and/or local tumour control. A large number of studies show that recombinant human erythropoietin (r-HuEPO) is effective in the treatment of tumour-induced anaemia and prevention and correction of chemotherapy and radiotherapy-induced anaemia. The simultaneous application of r-HuEPO with chemotherapy can prevent patients with head and neck tumours from developing anaemia or can reduce the extent of the anaemia and the need for transfusion. Comparable effects were observed both in patients undergoing platinum-based and non-platinum-based chemotherapy. The direct correlation between anaemia, tumour hypoxia and poor response to radio and/or chemotherapy has been clinically proven. Recombinant human erythropoietin administration improves the therapeutic outcome and the patients' prognosis.

Anemia↗
PubMed2000

[Robotics].

Content of this paper is the current state of the art of robots in surgery and the ongoing work on the field of surgical robotics at the Clinic for Maxillofacial Surgery at the Charité. Robots in surgery allows the surgeon to transform the accuracy of the imaging systems directly during the intervention and to plan an intervention beforehand. In this paper firstly the state of the art is described. Subsequently the scientific work at the clinic is described in detail. The paper closes with a outlook for future applications of robotics systems in maxillofacial surgery.

Humans↗
PubMed2000

Engaging staff nurses in evidence-based research to identify nursing practice problems and solutions.

This article illustrates how one academic health science center in a large metropolitan area sought to improve the quality of patient care by soliciting the input of their nursing staff in devising an action plan for change. The research model incorporated both survey and focus group methods used by nursing leaders in administration and practice to identify and prioritize nursing research and clinical needs in their organization. The goal was to establish consensus among clinicians and researchers about significant issues in the institution requiring in-depth attention. A second objective was to design a survey instrument that is easy to complete and could be distributed, collected, and analyzed easily, thereby providing empirical data to the clinicians in a timely manner and in a simple format. This expedited process enabled specific action plans to be developed around the identified problems. Moreover, the process promoted interest in advancing nursing research and evidence-based practice among the clinicians and administrators.

Adult↗
PubMed2000

Immunohistochemical assessment of the tumour-associated epitopes CD44v6 and E48 in tumour-free lymph nodes from patients with squamous cell carcinoma in the head-neck region.

We examined immunohistochemically 370 tumour-free lymph nodes from 41 patients with a head and neck squamous cell carcinoma (HNSCC) to clarify whether the tumour-associated epitopes CD44v6 and E48 are suitable for adjuvant postoperative immunotherapy. All the positively immunostained cells found were single cells. CD44v6+ cells were found in 55% of the lymph nodes, with their numbers increasing in pN>0-patients (62%). Only pN>0-patients had abundant to massive CD44v6+ cells. A comparison with mononuclear cells in lymphatic tissue from control patients suggested a similarity with activated T-cells. In the 41 cancer patients there were significantly fewer lymph nodes with E48+ cells (11%), but the number of E48+ cells increased in pN> 1-patients (29%) with predominantly abundant E48+ cells. We conclude from the comparison with the epithelial marker EMA that the E48+ single cells are epithelial in origin. Only a specific E48 peptide sequence appears suitable for adjuvant immunotherapy in patients with head-neck tumours.

Aged↗
PubMed2000

Reconstruction of the contracted ocular socket with free full-thickness mucosa graft.

Patients who have undergone enucleation of the eye can be treated with glass eye prostheses, provided retention is adequate. Inadequate retention due to contraction of the conjunctival mucosa is a common problem which frequently affects the lower fornix first. This can be corrected using a free full-thickness buccal mucosa graft. Indications, operative procedures and postoperative results are presented.

Adult↗
PubMed1999

[Bilateral rehabilitation with an implant-anchored orbital prosthesis].

From the aesthetic point of view, a patient can be completely rehabilitated after the loss of an eye with the insertion of an artificial eye made of glass. If the delicate structures of the eyelids have been severely damaged, however, or if the eye socket does not provide adequate retention for an eye prosthesis, rehabilitation becomes more difficult, and sometimes cannot be achieved with a cosmetically satisfactory result. In such cases, a facial prosthesis offers an alternative solution. Stable retention can be ensured with craniofacial implants. Single-sided rehabilitation by this method is quite common, but bilateral treatment is a rarity. We report on the prosthetic rehabilitation of a patient after exenteration on both sides due to retinoblastomas.

Adult↗
PubMed1999

[3D-computed tomography for spatial arrangement of the cranial bones of the human fetus].

Aim of the study was to assess the value of in vitro three-dimensional computed tomography (3D-CT) as a new method for the depiction of the fetal skull. 3D-CT images of a fetal head of 24 weeks gestational age were generated with the implemented software on the basis of contiguous CT slices of 1 mm thickness. 3D-CT gave real three-dimensional information about morphology and spatial arrangement of the cranial bones. Using cutting and rotating procedures fast evaluation of all imaged ossified structures in arbitrary views without disturbing superpositions was possible, thus allowing easy identification and accurate description of the cranial bones and making isolated examinations of particular macroscopic sections of the specimens unnecessary. Advantages of 3D-CT over other evaluation techniques for the fetal cranium and its limitations are discussed. In conclusion, 3D-CT promises to be an effective tool for the investigation of fetal cranial development.

Fetus↗
PubMed1999

Camouflage in head and neck region--a non-invasive option for skin lesions.

The technique of camouflage, a non-invasive procedure to correct flaws in the texture and colour of the facial skin, is presented. The acceptance and use of camouflaging by 52 patients with different diagnoses are presented. The advantages of camouflaging are discussed in comparison to medical tattooing.

Adult↗
PubMed1998

Simultaneous analysis of 4- and 5-series lipoxygenase and cytochrome P450 products from different biological sources by reversed-phase high-performance liquid chromatographic technique.

Quantification of lipoxygenase and cytochrome P450 products of both arachidonic acid (AA) and eicosapentaenoic acid (EPA) is of broad interest due to the multiple biological activities of these compounds. We developed a method combining (i) solid-phase extraction, (ii) isocratic reversed-phase high-performance liquid chromatographic separation, and (iii) online photodiode array detection with spectrum analysis for identification and measurement of all main 4- and 5-series eicosanoids (leukotrienes, hydroxyeicosatetraenoic acids/hydroxyeicosapentaenoic acids, epoxyeicosatrienoic acids) within one run. With these procedures, standard mixtures of AA- and EPA-derived lipid mediators were recovered from different biological liquids, like lung perfusate, human bronchoalveolar lavage fluid, and cell supernatant with linear characteristics for each compound. Recoveries of the different lipid mediators exceeded 80% showing excellent reproducibility. Application of the method to isolated, perfused, and ventilated human lungs challenged with the calcium ionophore A23187 and to human neutrophils stimulated in the presence of arachidonic acid and eicosapentaenoic acid with N-formyl-methionyl-leucyl-phenylalanine demonstrated the generation of a large array of lipoxygenase and cytochrome P450 products. Thus, convenient quantification of 4- and 5-series eicosanoids in fluids of biological interest is achieved by a technique comprising solid-phase extraction, isocratic reversed-phase high-performance liquid chromatography, and photodiode array-based online spectrum analysis of eluting compounds.

Arachidonate 5-Lipoxygenase↗
PubMed1998

Morphology of the development of the sagittal suture of mice.

Syndesmotic sutures of the skull are formed by dense connective tissue and called "open"; they are "closed" by formation of a synostosis between adjacent bones. Open sutures are considered as areas of growth and as hinges. The importance of open sutures during the period of skull growth is reflected by pathological situations in which premature closure of the sutures occurs. As alterations of the FGF receptor have been reported in genetical disorders accompanied by premature suture closure (Bellus et al. 1996), the role of fibroblasts and connective tissue in the development of the sagittal suture of mice has been investigated by light and electron microscopy. Morphological changes of the sagittal suture at the following stages are reported: at embryonic day 18, days 1, 5, 9, 14, 20, 26, 28 after birth and in adult mice. Two skulls per stage were investigated. Early osteogenesis appeared in a thin plate, followed by a second plate underneath the first one. Both were separated by blood vessels. In general, vascularization preceded desmoid mineralization; the space around blood vessels was occupied by non-bone-forming cells leaving cavities for the presumptive bone marrow. Mineralization of the collagen-rich osteoid at the mineralizing rim of the bone plates was accompanied by apoptoses and cell disintegration. Newly formed bone was immediately covered by osteoblasts forming a sheet of bone-lining cells. At day 9, the double-layered bone plates of both sides reached the median area of the skull but were separated by non-mineralizing, collagen-rich connective tissue. From day 14 onwards, the bone plates thickened. Bone apposition, recognizable by the formation of collagen-rich osteoid and proceeding from day 14 pp onwards, occurred mainly at the outer and inner surfaces of the calvariae, but neither at bone marrow surfaces nor at the medial edges of the parietal bones. These opposite bone faces showed fewer osteoblasts and bone-lining cells, but an increased number of fibroblasts. Tendon-like collagen bundles connected both bone plates of the open suture of day 26 pp as well as in the adult mice, whereby synostotically closed areas alternated. Formation of an open, syndesmotic suture can, therefore, be described as a transition of bone-forming tissue into a bone-tendon junction. The results indicate the importance of the replacement of osteoblasts by fibroblasts at the sutural front of the bone plates in order to prevent a premature suture closure.

Animals↗
PubMed1998

Custom-made cast titanium implants produced with CAD/CAM for the reconstruction of cranium defects.

Titanium implants for the reconstruction of bony skull defects, using data from three-dimensional spiral computer tomography, have been described by other authors. Instead of milling the implants from a titanium block, an advanced method of rapid prototyping for a fine casting process is presented. Casting vs milling offers several advantages. It is possible to form very thinly tapered structures and to obtain more complex geometrical structures with smaller diameters. Many geometrical forms, which cannot be milled for technical reasons, can be produced using this technique.

Adult↗
PubMed1998

Assessment of vascularity in reactive lymph nodes by means of D-galactose contrast-enhanced Doppler sonography.

RATIONALE AND OBJECTIVES: A prospective study in signal-enhanced Doppler sonography of lymph nodes that were assumed pretherapeutically to be benign was performed to investigate characteristic sonomorphologic features and vascularity of reactively enlarged lymph nodes. METHODS: Thirty-four patients with enlarged superficial lymph nodes of the neck were examined first by B-scan sonography then by Doppler sonography before and after administration of an ultrasound signal-enhancing agent. In B-scan sonography, lymph nodes were classified into three groups according to their sonomorphologic features: (1) homogeneous parenchyma, (2) a centrally located echogenoic line, and (3) a echogenoic "hilus reflex." In conventional and contrast-enhanced Doppler sonography, peak flow rate, pulsatility index, and resistive index were assessed. Sonomorphologic criteria were compared with histologic findings. RESULTS: Reactively enlarged lymph nodes showed characteristic sonomorphologic patterns correlating to their histologic features. Echogenicity of the hilus corresponded to fibrosis (centrally located echogenoic line in 13 nodes; 38.2%) or fatty involution of the hili (echogenoic hilus reflex in 15 nodes; 44.1%). Administration of the galactose-based ultrasound contrast enhancer facilitated the assessment of hilar vessels, which projected to the echogenoic hili, respectively, actually additionally visualized a hilar vascularity in 10 of the 34 lymph nodes compared with conventional Doppler. Measured Doppler indices gave not a significant clue for identifying reactive lymph nodes or for differential diagnosis. CONCLUSIONS: Qualitative sonomorphologic assessment of characteristic sonomorphologic features of reactive lymph nodes may serve as a valuable tool for examining reactively enlarged lymph nodes. Administration of an ultrasound echo enhancer allows the assessment of a characteristic nodal vascularity in reactive lymph nodes and were superior to conventional B-mode and conventional Doppler sonography.

Adult↗
PubMed1998

[The assessment of skin tumors with magnetic resonance with high resolution and a paramagnetic contrast medium].

INTRODUCTION: The technologic improvement of surface coils in MRI has allowed better visualization of the skin and thus permitted the clinical use of this technique in dermatology. MRI allows to assess the depth and extent of skin tumors and to detect any malignant transformation. The MR differentiation between benign and malignant skin lesions relies on morphological criteria which however do not have an absolute diagnostic value. We investigated the role of paramagnetic contrast agents in the differentiation between benign and malignant skin lesions. MATERIAL AND METHODS: Forty-one patients, 33 with benign and 8 with malignant skin tumors, were submitted to MRI. All the examinations were performed with a 1.5 T superconductive unit, with a 2.5 cm surface coil. Axial T1- and T2-weighted SE images were acquired with 2 mm slice thickness. Paramagnetic contrast material was administered to all patients. The signal intensity of the skin lesions was calculated before and after paramagnetic contrast agent administration positioning a region of interest. A percentage ratio of contrast enhancement was calculated to quantify contrast agent uptake and the relative values were compared between benign and malignant lesions. A qualitative analysis was also performed rating the contrast enhancement of each lesion as high, intermediate, or absent. RESULTS: The quantitative analysis showed a statistically significant difference (p < .5) between the contrast enhancement values of benign and malignant lesions. In particular, malignancies had values ranging 117.3 (+/- 28.7) to 125 (+/- 32.4), while benign lesions had -20.6 to 99.8 (+/- 21.1). Conversely, no difference in contrast enhancement was found at qualitative analysis. CONCLUSIONS: MRI is a promising tool for characterizing skin tumors. Our preliminary results should be confirmed on larger series of patients with the use of high temporal resolution imaging sequences.

Adolescent↗
PubMed1997

[A phase-I/II study on the local hyperthermia of cervical N2/N3 lymph node metastases].

BACKGROUND: Patients with advanced lymph node metastases from head and neck tumors at stage N2/N3 (i.e. UICC IV) present a difficult therapeutic problem. Despite combined radio-chemotherapy and hyperfractionated and/or accelerated fractionation regimens, local control of these tumors remains unsatisfactory. For this reason, the value of local radio wave/microwave hyperthermia was examined for this patient group in a phase I/II study.

Adult↗