PubMed Health⌕ Search

Biomedical subjects

A Faust

Publications and source records attributed to A Faust.

16 recordsLinked to original sources
PubMed2006

Partial sensory and motor deficit of ipsilateral lower limb after continuous interscalene brachial plexus block.

We describe a partial sensory and motor block of the ipsilateral lower limb after interscalene infusion. After and injection of 20 mL of ropivacaine through the needle, the catheter was advanced 5 cm, and an infusion of ropivacaine 0.2% 5 mL/h commenced. Six hours later, the patient reported a left sensory and motor hemisyndrome, which resolved after the infusion was discontinued. Cervical computed tomography showed the tip of the catheter close to the intervertebral foramen at the C7-T1 level and several intravertebral paramedullar air bubbles. We conclude that the neurological symptoms were caused by an injection of local anesthetic via an interscalene catheter placed in proximity to the epidural space. To avoid this complication, we recommend advancing the catheter no more than 2-3 cm and performing frequent neurological evaluation of patients.

Adult↗
PubMed2006

Molecular imaging of matrix metalloproteinases in vivo using small molecule inhibitors for SPECT and PET.

Matrix metalloproteinases (MMPs) are a family of zinc- and calcium-dependent secreted or membrane anchored endopeptidases. MMPs are involved in many physiological processes but also take part in the pathophysiological mechanisms responsible for a wide range of diseases. Pathological expression and activation of MMPs are associated with cancer, atherosclerosis, stroke, arthritis, periodontal disease, multiple sclerosis and liver fibrosis. Thus, noninvasive visualisation and quantification of MMP activity in vivo are of great interest in basic research and clinical application. This can be achieved by scintigraphic molecular imaging techniques such as single photon emission computed tomography (SPECT) and positron emission tomography (PET) provided suitable radiolabelled tracers exist, e.g. radioactive inhibitors of matrix metalloproteinases (MMPIs). The approach to monitor MMP activity in vivo using radiolabelled small molecule inhibitors suitable for SPECT and PET is summarised in this review. Briefly, latest advances in scintigraphic imaging are introduced and followed by a report about the enzyme class of MMPs. The involvement of MMPs in cancer and atherosclerosis is exemplified and small molecule MMPIs are classified. Subsequently, the development of radiolabelled small molecule MMPIs, their synthesis and in vitro and in vivo evaluation is reviewed. Finally, an outlook on the clinical potential of labelled MMPIs in diagnostic algorithms is given.

Animals↗
PubMed2005

Three-dimensional dynamic hip contact area and pressure distribution during activities of daily living.

Estimation of the hip joint contact area and pressure distribution during activities of daily living is important in predicting joint degeneration mechanism, prosthetic implant wear, providing biomechanical rationales for preoperative planning and postoperative rehabilitation. These biomechanical data were estimated utilizing a generic hip model, the Discrete Element Analysis technique, and the in vivo hip joint contact force data. The three-dimensional joint potential contact area was obtained from the anteroposterior radiograph of a subject and the actual joint contact area and pressure distribution in eight activities of daily living were calculated. During fast, normal, and slow walking, the peak pressure of moderate magnitude was located at the lateral roof of the acetabulum during mid-stance. In standing up and sitting down, and during knee bending, the peak pressures were located at the edge of the posterior horn and the magnitude of the peak pressure during sitting down was 2.8 times that of normal walking. The peak pressure was found at the lateral roof in climbing up stairs which was higher than that in going down stairs. These results can be used to rationalize rehabilitation protocols, functional restrictions after complex acetabular reconstructions, and prosthetic component wear and fatigue test set up. The same model and analysis can provide further insight to soft tissue loading and pathology such as labral injury. When the pressure distribution on the acetabulum is inverted onto the femoral head, prediction of subchondral bone collapse associated with avascular necrosis can be achieved with improved accuracy.

Computer Simulation↗
PubMed2005

Non-invasive molecular imaging of beta-adrenoceptors in vivo: perspectives for PET-radioligands.

Recently, the spectrum of molecular imaging devices such as positron emission tomography (PET) was further expanded by the now clinically available combined imaging modalities such as PET-CT and the preclinically used small animal PET scanners. These are powerful tools that can bridge the gap between preclinical and clinical evaluation studies of new radiotracers for molecular imaging of healthy and diseased states in vivo. The beta-adrenoceptor (beta-AR) radioligands discussed in this review represent a class of molecular probes for the non-invasive in vivo assessment of beta-AR density eg. in the heart with PET. The beta-AR radioligands (S)-[11C]CGP 12177 (1) or (S)-[11C]CGP 12388 (2) are currently investigated in clinical studies with PET. Additionally, subtype-selective beta1-AR radioligands are used in preclinical research which show potential for the diagnostics of the "beta1-AR organ" as such the heart can be defined. Non-invasive quantification of beta-ARs could facilitate the accurate choice and control of therapeutic interventions. Here we summarize the state-of-the-art of the radiochemistry of radioactive beta-AR radioligands.

Adrenergic beta-Agonists↗
PubMed2003

Advanced crown and bridge design.

The present article describes the CAD construction procedure of copings, reduced crowns, anatomical crowns, hybrid bridges, and other construction software features contained in the Digident dental CAD/CAM system (Girrbach Dental, Pforzheim, Germany). The individual design of a crown or a bridge framework will, of course, influence the stability and the longevity of the final dental restoration. Especially an anatomically reduced crown framework possesses--in comparison to a simple coping design--several advantages, while for some materials, a full crown design is esthetically not suitable. An anatomically reduced crown design results in a mechanical support of the occlusal cusps, as the high strength framework is mechanically more favorable than the veneering ceramics or composites. Moreover, the reduced construction of the anatomical shape allows the creation of ceramic layers of approximately homogeneous thickness. This has the effect that the residual stresses in the veneering ceramic after the thermal treatment, i.e., several firing and cooling cycles, are minimized. A prerequisite for the computer-aided anatomical construction of crowns is the inclusion of adjacent teeth and the articulation of the opposing jaw. In these terms, the opposing jaw or a bite impression have to be scanned, digitized, and positioned virtually in bite relation. While taking patient-specific articulator parameters into account, a software-integrated "virtual articulator" allows simulation of dynamic occlusion and therefore a computer-aided reduction of interfering contact points.

Computer-Aided Design↗
PubMed1997

Virtual reality (VR) techniques in orthopaedic research and practice.

Modeling the musculoskeletal joint system using biomechanical analysis and computer graphics techniques allows us to visualize normal, diseased and reconstructed joint function. This model can be used to study the loading of bones and joints under theoretical and simulated activities. In this study, intact cadavers were imaged using MRI, CT scanning and cryo-sectioning techniques. Using sequential pixel information of bone and soft tissue boundaries collected from digital camera images, MRI and CT scans, the volumetric models of the musculoskeletal joint system are reconstructed. "Descriptive geometry" techniques which treat bones as rigid bodies and cartilage, ligament and muscles as deformable bodies were used to construct the model. Joint resultant forces and moments were determined using an inverse dynamics formulation, while ligament tension, joint contact pressure, and bone stresses are solved through a simplified Rigid Body Spring Modeling technique and the Finite Element Method. The results under static and dynamic loading activities can be visualized using interactive computer graphics. The advantages of such a model are the elimination of the need for large numbers of intact cadaveric specimens, and the unprecedented capability to study joint loading responses under normal, abnormal and surgically reconstructed states. Such a model and its analytical capability are ideal for pre-operative planning and computer-assisted orthopaedic surgery. This Visual, Interactive, Computational, and Anatomic Model(VICAM) and its associated analysis capability represent the next generation of technology which will have an enormous impact in orthopaedic research, education and patient care.

Biomechanical Phenomena↗
PubMed1996

Primary nonfunction of islet grafts in autoimmune diabetic nonobese diabetic mice is prevented by treatment with interleukin-4 and interleukin-10.

In isologous islet transplantation in spontaneously diabetic nonobese (NOD) mice, destruction of the islet graft is caused by recurrence of T helper (Th)1-driven insulitis[fnc,1. We established a model of transplantation in which female NOD recipients were rendered diabetic by a single injection of cyclophosphamide (250 mg/kg). Under these conditions, 500 freshly isolated islets from young NOD mice transplanted under the kidney capsule did not lead to normoglycemia within 3 day after transplantation, but underwent immediate impairment of function. This primary nonfunction was seen in > 80% of the recipients. Treatment of the recipients with the Th2-associated cytokine interleukin (IL)-4 alone did not prevent primary nonfunction, whereas treatment of the recipients with a combination of IL-4 and IL-10 restored immediate function of the grafts. Cytokine treatment did not prevent later rejection of grafts. Histological analysis of the grafts revealed less severely infiltrated islets, with well preserved islet architecture, in only normoglycemic animals treated with IL-4 or with IL-4 and IL-10. Staining for lymphocytes, macrophages, and tumor necrosis factor (TNF)-alpha did not show differences between the groups, but IFN-gamma was markedly less expressed in IL-4- and IL-10-treated grafts. Concomitantly, analysis of animals treated for 8 days after injection of cyclophosphamide, with IL-4 and IL-10, revealed a reduction of IL-12 mRNA in the pancreas. We conclude from these data that primary nonfunction of islet grafts is prevented by treatment of the recipients with a combination of IL-4 and IL-10, via downregulation of Th1 cytokines.

Animals↗
PubMed1996

Differential expression of ICAM-1 and LFA-1 versus L-selectin and VCAM-1 in autoimmune insulitis of NOD mice and association with both Th1- and Th2-type infiltrates.

The infiltration of pancreatic islets by mononuclear cells is the hallmark of the development of insulin dependent diabetes mellitus (IDDM) in the NOD mouse, an animal model for human IDDM. The aim, of this study was to correlate adhesion molecule expression with the degree of islet infiltration and to compare Th1- and Th2-driven islet inflammation. Cryostat sections of NOD mouse pancreata before and after diabetes development were analysed by semiquantitative immunohistochemistry. NOD mouse islets did not show the expression of ICAM-1, LFA-1, L-selectin and VCAM-1 prior to infiltration by mononuclear cells. Furthermore, islets with early stage insulitis (grade 1, periinsular location of small infiltrates) still were devoid of adhesion molecule expression. ICAM-1 and LFA-1 were first demonstrable in islets with strong periinsular infiltrates (insulitis grade 2) while L-selectin and VCAM-1 were only seen in islets with mild or strong intraislet infiltration (grade 3-4). Adhesion molecules were demonstrable in areas of macrophage and T-lymphocyte infiltrates but not in adjacent endocrine islet tissue. Islets of all infiltration stages contained Th2 lymphocytes (positive for IL-4). Substantial numbers of Th1 cells (positive for IFN-gamma, TNF-alpha, IL-2 and/or IL-2 receptor) were observed only after acceleration of diabetes development by a single injection of cyclophosphamide (250 mg/kg i.p.). Interestingly, the adhesion molecule expression pattern in islets with "Th1' versus "Th2 insulitis' was not different. In conclusion, the expression of adhesion molecules in islets during the development of autoimmune diabetes does not precede mononuclear infiltration but probably occurs in response to the activation of initial small infiltrates. ICAM-1 and LFA-1 expression is seen prior to L-selectin and VCAM-1. However, adhesion molecule expression during Th1 versus Th2 cell infiltration is very similar, suggesting similar adhesion molecule requirements of the two Th subsets.

Animals↗
PubMed1996

Interleukin-12 gene expression is associated with rapid development of diabetes mellitus in non-obese diabetic mice.

A single dose of cyclophosphamide (250 mg/kg) is known to synchronize and accelerate development of diabetes in non-obese diabetic mice. We have reported previously that cyclophosphamide treatment of 10-week-old female non-obese diabetic mice induces a shift from T-helper type 2 to T-helper type 1 activity in islet lesions. We now show that this shift in regulatory T-cell function is preceded by the expression of interleukin-12 in the islets as well as in the spleen. In the spleen macrophages were identified as the interleukin-12 expressing cell type. At the same time there was little induction of tumour necrosis factor alpha gene expression by macrophages. Since interleukin-12 is well known to drive T-helper cell type 1 responses we assume that interleukin-12 released by macrophages mediates the accelerating effect of cyclophosphamide on islet inflammation in non-obese diabetic mice. mRNA expression of the p40 chain of interleukin-12 in response to cyclophosphamide was not seen in macrophages of Balb/c mice and thus represents an immune abnormality of non-obese diabetic mice favouring T-helper type 1 reactions.

Animals↗
PubMed1994

Cyclophosphamide treatment of female non-obese diabetic mice causes enhanced expression of inducible nitric oxide synthase and interferon-gamma, but not of interleukin-4.

In pancreatic lesions of non-obese diabetic (NOD) mice the expression of inducible nitric oxide synthase (iNOS) and of the cytokines interferon-gamma and interleukin-4 were studied. Strong iNOS expression as determined at the level of transcription, translation and of enzyme activity was associated with destructive insulitis as seen 8-10 days after cyclophosphamide treatment of 70- to 80-day-old female NOD mice. Immunohistochemistry showed iNOS associated with infiltrating macrophages but not in endocrine cells. The enhancement of iNOS after cyclophosphamide correlated with an increase of T-helper type 1 (Th1) associated interferon-gamma expression while T-helper type 2 (Th2) associated interleukin-4 was the dominant cytokine prior to cyclophosphamide and after diabetes onset. We conclude that insulitis in young NOD mice is carried by Th2 cells while cyclophosphamide enhanced insulitis is determined by Th1 cells. Macrophages show two different functional states in insulitis; strong iNOS expression in macrophages is associated with destructive insulitis.

Amino Acid Oxidoreductases↗
PubMed1994

Effect of lipoic acid on cyclophosphamide-induced diabetes and insulitis in non-obese diabetic mice.

In an animal model of type I diabetes, the non-obese diabetic (NOD) mouse, the influence of the antioxidant lipoic acid (LA) on the development of diabetes was investigated. Acceleration of diabetes development with cyclophosphamide (CY) resulted in 60% diabetic animals with severely infiltrated islets within 1-3 weeks. Daily administration of lipoic acid for 20 or 30 days around cyclophosphamide treatment suppressed the incidence of diabetes to 30% (P < 0.05) and 33%, respectively. Semiquantitative analysis of islet infiltration showed a reduction of severe intraislet infiltration and an increase in the percentage of islets with mild per-insular and periductular infiltrates (from 8.4 to 29.6 and 25.9%, respectively, P < 0.01) after lipoic acid treatment. These results show that the protective effect of lipoic acid on diabetes development correlates with partial suppression of islet inflammation. The anti-inflammatory action of lipoic acid may be due to its ability to scavenge oxygen radicals and to suppress nitric oxide production.

Animals↗
PubMed1994

Circulatory clearance of transfused antibody-sensitized red cells in an entirely allogenic rabbit model.

BACKGROUND: Antibodies against histocompatibility antigens on phagocytes abrogate their Fc gamma-receptor-mediated functions in vitro. Studies were carried out to determine whether this phenomenon also exists in vivo. METHODS: An allogenic blood group antibody was generated in rabbits. Red cells sensitized with this antibody were internalized in vitro by rabbit phagocytes. Another allogenic antibody specific for major histocompatibility complex (MHC) antigens of rabbits was produced. Plasma containing this antibody was infused into rabbits with phagocytes expressing the corresponding MHC antigens. Thereafter, the sensitized rabbit red blood cells were transfused into the rabbits. RESULTS: The following 3 phases of the circulatory clearance of transfused sensitized red cells could be observed when MHC antibodies were not given prior to the transfusion: 1. initial rapid clearance of the cells (t/2 = 1.7-3.3 min), 2. release of the cells back into the circulation after 0.5-24 h and 3. terminal slow clearance which was, however, faster than that with unsensitized cells. Two independent experiments carried out on the same recipient out of the 3 recipients analysed showed that the prior treatment of the recipient with MHC-alloantibodies extended the circulatory half-life of the sensitized red cells during the terminal phase from t/2 = 1 day to t/2 = 3 and 4 days, respectively. CONCLUSION: Antibodies against MHC antigens on phagocytes can reduce the Fc gamma-receptor-mediated immune elimination of sensitized red cells. This corresponds to the observation that many cases of morbus haemolyticus neonatorum show unexpectedly reduced levels of foetal red cell destruction and a good clinical outcome if mothers not only produce antibodies to Rh (D) but also to foetal MHC antigens.

Animals↗
PubMed1987

Detection of antibodies specific for HLA-A,B,C,DR,DQ and DP by the erythrocyte antibody rosette inhibition (EAI) and immune phagocytosis inhibition (IPI) tests.

Two methods for the detection of murine monoclonal antibodies against determinants of the human major histocompatibility complex (MHC) were evaluated. These methods are based upon the function of Fc receptors; the erythrocyte antibody rosette inhibition test (EAI test) using B-lymphocytes and the immune phagocytosis inhibition test (IPI test) using monocytes. Compared to the EAI test the IPI test was technically easier and gave better discrimination between positive and negative results. The inhibition by antibodies of monomorphic class II MHC or polymorphic HLA-DR antigens was stronger in the IPI than in the EAI test. Antibodies against HLA-DQ and DP antigens evoked inhibition only using the EAI test. Using IgG derived from placenta in different dilutions the detection of its anti-HLA antibodies was more readily achieved in the IPI test than in the EAI test.

Antibodies, Monoclonal↗
PubMed1984

Effect of calibration material lot changes on results for the "SMAC".

The effect of two changes of calibration material (separated by five months) for the SMAC continuous-flow analyzer was followed by means of five quality-control indices: three normal and abnormal control sera, the mean of the central 50th percentile of patients' results, and the mean value for normal individuals. After the first and second changes of calibration materials, eight and six, respectively, of the 20 different tests exhibited statistically significant changes as shown by the indices. The cumulative shift for two of the 20 tests was considered medically significant. Prospective studies on split samples of patients' sera before the change in calibration material only predicted half the significant changes in test results later evidenced by the above-mentioned indices.

Autoanalysis↗
PubMedDate not supplied

Concentrations and profiles of PCDDs and PCDFs in human mammary carcinoma tissue.

PCDD/PCDF concentrations in eight mammary carcinoma tissue samples obtained after surgical excision were similar to those found in two healthy breast glandular tissue samples from autopsy material. These levels agree well with mean concentrations in human adipose tissue from German adults. An analogous consistency was found for the congener profiles of the normalized concentrations, also in comparison with mothers' milk from Germany. In spite of similar congener profiles the concentrations in four axillary adipose tissue samples corresponding to the carcinoma samples were about 40% lower. This discrepancy was not found in one tissue pair from a healthy breast.

Adipose Tissue↗