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Biomedical subjects

C Rust

Publications and source records attributed to C Rust.

27 records · Page 2Linked to original sources
PubMed1996

Intravenous coronary angiography with dichromography using synchrotron radiation.

Dichromography represents a digital subtraction angiography mode based on energy substraction which allows imaging of fast moving subjects like the heart. For logarithmic subtraction 2 images with X-rays just below and above the iodine K-edge (33.17 keV) are simultaneously obtained in a line scan mode. Monochromatic X-rays of sufficient intensity to visualize coronary arteries of 1 mm diameter with extremely low iodine concentrations (1 mg/cm2) after venous injection is only provided by synchrotron radiation. The system NIKOS (non-invasive coronary arteriography with synchrotron radiation) at the Deutsches Elektronen Synchrotron (DESY) consists of 6 components: a wiggler, a monochromator, a safety system, a scanning device, a detector and a computer system. After experimental studies in dogs patients are imaged since 1990. Initial results demonstrate feasibility and safety of synchrotron radiation coronary angiography. Large scale studies are designed to further evaluate sensitivity and specificity. When compact synchrotron radiation sources become available, this technique could be used for follow-up studies and for evaluation of certain high coronary risk populations.

Angiography, Digital Subtraction↗
PubMed1996

An open trial of nefazodone in adult patients with generalized anxiety disorder.

Generalized anxiety disorder (GAD) is a chronic disorder for which a variety of medications have been prescribed. Nefazodone is a recently released antidepressant that potently antagonizes the serotonin type 2A receptor and blocks uptake of norepinephrine and serotonin. It also antagonizes the serotonin type 2C receptor. Studies suggest this action may be anxiolytic. Twenty-one patients meeting DSM-IV criteria for GAD enrolled in an open 8-week trial of nefazodone were monitored by the Hamilton Rating Scale for Anxiety and the Clinical Global impressions scale. Fifteen of the 21 subjects completed the trial; 12 (80%) were rated as either very much or much improved, 1 (7%) as minimally improved, and 2 (13%) as unchanged. None was rated as worse. Nefazodone may be useful and well tolerated in the treatment of GAD. Theoretical questions about the neurobiological basis of GAD are also raised.

Adult↗
PubMed1994

[The value of spiral computed tomography in the imaging of aortocoronary bypass vessels].

Spiral computer tomography (Sp-CT) was performed on 25 patients with 81 aorto-coronary bypasses, with persistent symptoms, following selective coronary angiography. The purpose was to determine to what extent Sp-CT is able to demonstrate patency or occlusion of individual bypasses. From the raw data, transverse sections and standardised 3D reconstructions were obtained. Statistical evaluation showed a sensitivity of 93% and a specificity of 100% with regard to patency. Sp-CT provides optimal contrast and complete demonstration of the bypass without movement artifacts from respiration. 3D reconstructions aid in the evaluation of complex anatomical situations but occasionally lead to incorrect diagnosis of stenoses or occlusions. Compared with other non-invasive procedures (conventional CT and NMR) Sp-CT has proved significantly better for the evaluation of bypass occlusions. Sp-CT cannot completely replace angiography but in some cases may be an acceptable alternative.

Aged↗
PubMed1993

Reactivity of human gamma delta T cells to staphylococcal enterotoxins: a restricted reaction pattern mediated by two distinct recognition pathways.

Staphylococcal enterotoxins (SEs) are known superantigens for T cells expressing the alpha beta T-cell receptor (TCR). They bind to MHC class II molecules on antigen-presenting cells and can subsequently trigger T-cell responses by binding to V beta-gene products. The reactivity of gamma delta T cells with enterotoxins is less well defined although both proliferative and cytotoxic responses have been described. In the present study we have tested the cytotoxic reactivity of a panel of 41 gamma delta T-cell clones against target cells coated with the enterotoxins SEA, SEB, SEC1, SEC2, SEC3, SED, SEE or TSST. Three reaction patterns were observed with the gamma delta T-cell clones: (1) clones that specifically lysed SEA-coated target cells only; (2) clones that specifically lysed SEE-coated target cells only, and (3) clones that specifically lysed SEA-coated target cells only in the presence of certain human sera. The presence of SEA-specific antibodies in such human sera could be demonstrated. Moreover, gamma delta T-cell clones of this third category expressed the IgG FcRIII (CD16) which indicates that these clones are capable of mediating antibody-dependent cellular cytotoxicity towards SEA-coated target cells. Thus, the cytotoxic response of gamma delta T cells to SEs is mediated by two distinct pathways: an antibody-independent and an antibody-dependent pathway. The antibody-independent reactivity of gamma delta T cells was directed to either SEA or SEE, whereas antibody-dependent reactivity was found only towards SEA. The capacity of gamma delta T-cell clones to respond to stimulation with SEs, combined with their high cytolytic capacity in vitro, suggests that these cells can be involved in SE-directed immune responses and efficiently kill SE-coated target cells in vivo.

Clone Cells↗
PubMed1992

Staphylococcal enterotoxin-mediated human T-T cell interactions.

Staphylococcal enterotoxins (SE) are known to stimulate a large proportion of T cells. SE bind to MHC-class II molecules on APC and a particular segment of certain TCR V beta and V gamma gene products. Resting human T cells do not express HLA class II Ag and therefore cannot present SE to T cells. Activated human T cells, however, do express HLA-DR, -DP, and -DQ Ag and could consequently serve as APC for SE. As such, local immune responses to SE might be regulated and/or abrogated by SE-mediated T-T cell interactions leading to T cell destruction. We have investigated if such SE-mediated T-T cell interactions can occur in vitro using human cytolytic TCR-alpha beta+ and TCR-gamma delta+ T cell clones. We demonstrate that the TCR-alpha beta+ T cell clones can efficiently present staphylococcal enterotoxin A (SEA) to each other: T cell clones coated with SEA are lysed by SEA-reactive T cell clones but not by a SEA-nonreactive T cell clone. Furthermore, the SEA-reactive TCR-alpha beta+ clones (but not the SEA-nonreactive clone) destruct themselves in the presence of SEA at low concentrations of SEA (less than 0.01 microgram/ml). Also, SEA-coated T cell clones can induce proliferative responses although such responses are much weaker than those induced when B cells are used as stimulator cells. In contrast, the SEA-reactive TCR-gamma delta+ T cell clones are resistant to autokilling in the presence of SEA and they do not lyse SEA-coated TCR-gamma delta+ targets. However, such targets can be lysed by TCR-alpha beta+ effector cells. These results indicate that TCR-gamma delta+ cells are relatively resistant to lysis and that during local nonspecific immune responses triggered by SE, which induces HLA-class II expression by the responding T cells, SE-mediated T-T cell interactions may play a role in the regulation and/or abrogation of these immune responses.

Antigens, Bacterial↗
PubMed1992

Phenotypical and functional characterization of small intestinal TcR gamma delta + T cells in coeliac disease.

Increased numbers of TcR gamma delta + T cells are present in the small intestinal epithelium of patients with coeliac disease (CoD). Their function, however, is unknown. In order to facilitate detailed functional studies, intestinal gamma delta T cells have been isolated from small intestinal biopsies of patients with CoD (n = 18) and controls (n = 14). As expected, increased numbers of V delta 1+ TcR gamma delta + T cells were detected in freshly isolated intraepithelial cell suspensions (IEL) from CoD patients. Also, in the in vitro expanded IEL T-cell populations from CoD patients the numbers of V delta 1+ TcR gamma delta + T cells were increased compared with similar cell cultures from control patients. From IEL cultures derived from six CoD patients, 107 T-cell clones were generated by limiting dilution and analysed. Sixty of these clones were either CD4 or CD8 positive TcR alpha beta + clones. The remaining 47 clones expressed the TcR gamma delta. Further phenotypical analysis of the gamma delta T-cell clones indicated that the TcR gamma delta + T-cell population in the small intestinal epithelium of CoD patients is heterogeneous: four TcR gamma delta phenotypes could be detected and, although the majority of the TcR gamma delta + T cells were CD4 CD8, gamma delta T-cell clones expressing either a CD8 alpha alpha homodimer, a CD8 alpha beta heterodimer or CD4 were also identified. In contrast to the TCR alpha beta + IEL, most TcR gamma delta + IEL were CD5 negative. Furthermore, biochemical analysis indicated that the increase in V delta 1+ gamma delta T cells in the small intestinal epithelium of CoD patients was not the result of a monoclonal expansion. The small intestinal epithelium-derived gamma delta T-cell clones were functional in vitro since the majority of these clones were able to lyse target cell lines such as K562. Molt4 and Daudi. These novel findings therefore indicate that the gamma delta T cells in the small intestine of CoD patients represent a heterogeneous population and that such cells are functional in vitro. The isolation and the in vitro propagation and cloning of these cells may open new avenues for the study of the putative immune mechanisms leading to coeliac disease.

Adult↗
PubMed1985

Cardiopulmonary arrest due to misuse of viscous lidocaine.

A 30-month-old female infant had a cardiopulmonary arrest due to viscous lidocaine. The protective airway mechanisms were blunted by this drug, resulting in aspiration, hypoxia, seizures, and death. Lidocaine has also been associated with respiratory depression, psychosis, methemoglobinemia, and toxic cardiovascular reactions. We do not recommend the use of viscous lidocaine for minor oral irritation in infants and young children.

Candidiasis, Oral↗
PubMedDate not supplied

Using practice led design research to develop an articulated mechanical analogy of the human hand.

Contemporary prostheses have developed from small iterations on moderately successful archetypes. This has resulted in modern designs that can either be termed cosmetic or functional, with neither attribute being fully satisfied. A new strategy is needed to develop a generation of upper-limb prostheses that will integrate both cosmetic and functional requirements in a single device. It is hypothesized that design principles applicable to a new generation of prostheses will result from exploring close analogies to the human upper limb. A method of practice led design research has been adopted to explore appropriate analogies, using the production of physical models to elucidate the design problem to the design team and other interested parties. This method uses a consciously iterative approach whereby criticisms and lessons learnt in the development of early models are embodied in subsequent models. This paper describes the first iterative cycle. It includes a critical review of the devices currently available and a study of mechanical analogies to original anatomy which form two of the inputs to the development of a skeletal model hand. It details the lessons learnt from this study and concludes on the wider application of practice led design research in medical engineering.

Artificial Limbs↗