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Biomedical subjects

R Steiner

Publications and source records attributed to R Steiner.

At least 73 records · Page 4Linked to original sources
PubMed1995

Erbium:YAG laser photoablation of human cornea.

PURPOSE: To determine whether the healing response of the human cornea after photoablation with a midinfrared solid-state laser was more pronounced than after excimer laser keratectomies because of the increased thermal damage in adjacent tissue. METHODS: We treated five blind human eyes with an erbium:YAG (Er:YAG) laser prototype and followed up the patients for nine months. RESULTS: Regarding epithelial healing and corneal clarity, the patients had a healing response very similar to that of excimer laser. Further clinical and experimental studies are necessary to estimate healing and regression.

Aged↗
PubMed1995

'Et in arcadia ego...?' Some notes on methodological issues in the use of psychoanalytic documents and archives.

The author uses archival material, mainly the letters exchanged between Jones and Strachey in the fifties, when Jones was writing his biography of Freud and Strachey was working on the Standard Edition. He shows the complexity of the interaction between these two men; the more or less conscious ambivalences, motivations and resentments against the so-called Freudian establishment of that time. This per se can help us to understand how a 'certain image' of Freud was created in Great Britain during those years and the reasons for its authoritative persistence. Yet the paper touches on more general issues such as those of the fascination with psychoanalytic archives and the more or less accepted and admitted unconscious motivations of the interpreters of these documents too, not excluding myself. The conclusion reached is that even psychoanalytical documents do not rest in a peaceful Arcadia and that archives cannot be considered as the Arcadia of documents--at least not in the ways that Arcadia has always been considered and interpreted, misleadingly, even in two paintings by Poussin, which I refer to in my paper. These in reality remind us that in Arcadia there is death too. Even the memory that the documents should help us to conserve is ineluctably bound to loss, dissemination, mutilation and uncertainty, and therefore must also face the presence of death also.

Archives↗
PubMed1995

[Causal attributions and coping with illness by breast cancer patients: results of a longitudinal study].

The present 3-year longitudinal study investigated the relationship between causal attribution and coping mechanism. Data were collected in a group of 66 breast cancer patients by self-report questionnaires. Three issues were addressed: 1. How do the patients explain the cause of their illness? 2. Do the subjective causes change over the course of three years? 3. What kind of relationship can be found between the causal attributions and the coping mechanism of the patients? Results showed a predominance of psychological attribution. Only little statistical prove could be found for changes between the four ratings. Analysing the individual data of the patients however revealed changing perceptions for about half the patients. A relationship between psychological attribution and depressive coping and problem solving as well were found.

Adaptation, Psychological↗
PubMed1994

Thermal side effects of fiber-guided XeCl excimer laser drilling of cartilage.

We examined thermal effects during ablation of human joint cartilage using two XeCl excimer lasers with pulse durations of approximately 20 ns and 60 ns. An increase in radiant exposure or repetition rate caused a rise in tissue temperature up to 82 degrees C at a 100-microns distance. With increasing distance from the crater edge, the temperature dropped exponentially. Radiant exposures higher than 1.8 J/cm2 and repetition rates above 20 Hz lead to a formation of hot gaseous products escaping from the laser crater. When osteoarthritic cartilage is irradiated, these gases spread inside the tissue causing a temperature rise of > 50 degrees C at a distance of 1 mm from the crater edge. In the contact mode, we found a linear rise of ablation rate with increasing repetition rate both in air or saline. But ablation rates in saline were only half the rates achieved in air. Both phenomenons can be explained by additional thermal effects of excimer lasers working in the range of higher repetition rates and pulse energies.

Cartilage, Articular↗
PubMed1994

A follow-up dual-task investigation of lateralized effects in right- and left-handed males.

A dual-task follow-up investigation examined the influence of sample size and ideational complexity of cognitive tasks on lateralized effects. With a larger sample (n = 128), results showed a "manual dominance effect" for relaxed and paced nonideational vocalized tasks. A hierarchy of ideational verbal tasks yielded the expected lateralized effects which corresponded with increasingly greater interference in concurrent tapping, but not in strength of laterlized effect. Instead of a trend seen in the earlier work (Steiner, Green, & White, 1992), results revealed a significant difference between handedness groups for one complex spatial task. Finally, outcomes for the other spatial task highlight the importance of assessing tradeoffs in attention.

Adult↗
PubMed1994

'The Tower of Babel' or 'after Babel in contemporary psychoanalysis'? Some historical and theoretical notes on the linguistic and cultural strategies implied by the foundation of the International Journal of Psycho-Analysis, and on its relevance today.

The author uses private correspondence and documents referring to the foundation of the 'International Journal of Psycho-Analysis' and the 'Glossary' for translating Freud's work, to try to delineate the political and cultural strategy of Jones in founding and developing the 'International Journal of Psycho-Analysis'. Both strategies were based on the wish to have administrative and cultural control of psychoanalysis in the English-speaking countries. In the end Jones and his colleagues succeeded in making the language they created the official language of the IPA; through control of Freud's translations, through the 'Glossary' and particularly through its diffusion in the 'Journal'. The author briefly illustrates the various cultural sources of this attempt and tries to show the similarities between the project of Jones and the first generation of pioneers of psychoanalysis in Great Britain and the myth of the tower of Babel--one of its most important foundation stones being the 'International Journal'. Finally, the author stresses that those issues are still extremely alive in psychoanalysis today. But, confronted with the near-Babel of languages of contemporary psychoanalysis, can we still imply the existence of this universal common language and use it? Can the 'International Journal' still maintain its hegemony? Do we really understand each other even when we use the same technical terminology in English? Or shall we accept that today we should live without a tower of Babel in psychoanalysis? The author concludes that there is some hope, provided that we do not pursue meanings to the forbidden limit of the absolute.

Europe↗
PubMed1994

[Moist ablation of the corneal surface with the Er:YAG laser. Results of optimizing ablation].

The Er:YAG laser, emitting light at 2.94 microns, may be an alternative to the 193 nm excimer laser for photorefractive keratectomy. Compared to the excimer laser, the ablation rate is very high. Surface roughness is also more pronounced than for the excimer laser. Using a precorneal liquid film, these two factors can be reduced, as shown in ablation experiments performed on porcine corneas. Thermal damage of the remaining corneal tissue is another side effect. There is no significant decrease in the amount of thermal damage with this new technique,--not even when the pulse length is reduced.

Animals↗
PubMed1994

In Vienna veritas...?

The author focuses first on the cultural background which stimulated Freud and led to some of his conclusions on the importance and meaning of 'Oedipus Rex' and 'Hamlet' for his discovery of the Oedipus complex. He stresses the significance of Freud's education and the influence of the late eighteenth and nineteenth-century tradition of the German-speaking intellectuals. The author uses the sources of Freud's actual or possible readings from 1897 leading up to the publication of 'The Interpretation of Dreams' to support the evidence for his thesis of the complex interaction between Freud and his cultural background. The author tentatively tries to show that even post-Freudian interpretations of 'Oedipus Rex' cannot be considered without looking at parallel research taking place in fields other than psychoanalysis. He stresses the importance of myth in post-Freudian psychoanalysis and particularly focuses on the relationship between the myth of Narcissus and 'Oedipus Rex' and what this gave rise to. He concludes his paper by stressing that as Freud's interpretations of the 'Oedipus Rex' do show the influence of the cultural context in which he operated, the same can be said for our interpretations too. They are part of a changing historical process, but at the same time they contain some permanent values.

Austria↗
PubMed1993

Purification and characterization of recombinant Bet v I, the major birch pollen allergen. Immunological equivalence to natural Bet v I.

Pollen from trees of the order Fagales (e.g. birch, alder, hazel, oak, and hornbeam) are a major cause of Type I allergies observed in early spring. Previously, we reported the cloning and sequencing of Bet v I, the major birch pollen allergen, which showed high sequence similarities to a family of plant pathogen-activated genes (Breiteneder, H., Pettenburger, K., Bito, A., Valenta, R., Kraft, D., Rumpold, H., Scheiner, O., and Breitenbach, M. (1989) EMBO J. 8, 1935-1938). Here, we present the results on the expression, purification, and characterization of recombinant Bet v I produced in Escherichia coli as fusion and non-fusion protein, respectively. The purified recombinant proteins were analyzed to verify purity and structural integrity, and their immunological properties were compared to those of Bet v I isolated from birch pollen (natural Bet v I). Immunoblot analyses showed that the recombinant proteins are specifically recognized by monoclonal antibodies raised against natural Bet v I as well as by IgE from birch pollen-allergic patients. However, enzyme-linked immunosorbent assays revealed a decreased IgE-binding activity of the recombinant fusion Bet v I compared to the non-fusion and natural Bet v I proteins, which probably results from conformational changes due to the fusion tail. Recombinant non-fusion Bet v I was equivalent to natural Bet v I with respect to IgE-binding properties, the ability to induce in vitro proliferation of allergen-specific T-cell clones, and the ability to release histamine from basophils derived from birch pollen-allergic patients.

Allergens↗
PubMed1993

Solid-phase introduction and intracellular photoinduced reaction of a water-soluble meso-tetracarboxyporphine conjugated to an antisense oligodeoxyribonucleotide.

Oligonucleotide conjugated with water-soluble meso-tetra(4-carboxyphenyl) porphine (TPPC4) has been prepared by a supporting synthesis and novel solid-phase conjugation strategy. The conjugates could be used in dual fashion: i) on formation of iron complex, target DNA could be site-specifically cleaved on incubation with dithiothreitol; ii) on incubation of RR 1022 rat epithelial cell culture with non-metalized oligonucleotide TPPC4 conjugate, cytotoxic effect was detected after irradiation with laser light at 635 nm.

Animals↗
PubMed1993

In vivo photoproduct formation during PDT with ALA-induced endogenous porphyrins.

The administration of 5-aminolevulinic acid (ALA) in tumor-bearing nude mice leads to the formation of the fluorescent, photounstable photosensitizer protoporphyrin IX in tumor tissue. On-line fluorescence spectroscopy during photodynamic therapy (PDT) shows the in vivo formation of chlorintype photoproducts of protoporphyrin. The fluorescence of protoporphyrin as well as its photoproducts is bleached completely at the end of the PDT (100 J cm-2, 630 nm). These findings were also verified using ultrashort laser pulses and time-correlated single-photon counting. A photinduced shortening of the decay times and decrease in the integral fluorescence intensity were measured in vivo due to the photodestruction of the endogenous photosensitizer protoporphyrin IX in the tumor.

Aminolevulinic Acid↗
PubMed1993

[Effect of pulse duration of the Er:YAG laser on photoablation in ocular tissue (cornea and sclera)].

After photoablation in corneal and scleral tissue with the Er:YAG laser, two zones of thermal damage can be detected: The first zone (about 3 microns thick) consists of thermally denatured debris. The second zone (about 30 microns thick) shows a slightly more intense staining (H&E) compared to the non-influenced tissue. Variation of laser pulse duration between 100 microseconds and 1300 microseconds does not influence the extension of these two thermal damage zones. Furthermore, ablation rate and ablation volume remain nearly constant within this range of pulse durations. These data were obtained by histology (H&E staining) and with a recently published silicon cast replica method. All experiments have been performed on corneas and sclera of pig eyes.

Animals↗
PubMed1993

[Comparative study of ab-externo sclerostomy with the excimer and Er:YAG laser].

The specific ablative effect of pulsed 308 nm XeCl-excimer laser radiation (4 mJ 80 Hz) on the tissue has proved its worth in clinical use in glaucoma patients. However, the cytotoxic and mutagenic photochemical reactions induced by intraocular ultraviolet irradiation could theoretically be cataractogenic and retinotoxic. Unlike the excimer laser technique, ab externo sclerostomy with the Er:YAG laser (2940 nm/11 mJ, 7 Hz) excludes these risks. Histological and scanning electron microscope analysis of pig eyes showed thin, and smoothly limited zones of necrosis and only minimal irritation of the adjacent tissue and a slightly wavy surface. A newly developed handpiece for the Er:YAG laser enables energy transport via zirconium fluoride fiber and coupling to a quartz fiber tip with a core diameter of 320 microns. Er:YAG laser sclerostomy has so far been performed on 16 eyes in which the average preoperative IOP was 29 mmHg. The procedure took only a few minutes and the patients reported feeling no pain although retrobulbar anesthesia was not induced. The postoperative average IOP was less than 20 mmHg after 6 weeks and for the rest of a maximum observation period of 12 weeks. Reoperation was necessary in 2 cases. Er:YAG laser ab externo sclerostomy could be another alternative for the operative therapy of glaucoma.

Aged↗
PubMed1993

[Excimer laser sclerostomy of secondary glaucoma].

Initial results after nine ab externo sclerotomies on seven patients awaiting enucleation because of intensive pain caused by secondary glaucoma have encouraged us to present the methods used for this technique of fistula construction and the course in these patients. A special applicator permits precise manual positioning of the excimer laser beam (lambda = 308 nm) subconjunctivally at the limbus using a quartz-quartz fiber (diameter: 0.32 mm). The energy applied at the fibertip is 4 mJ per pulse, with a repetition rate of 80 Hz. All patients undergoing the operation, which lasted only a few minutes, were treated as out-patients without a retrobulbar anaesthesia. Because of the minimal irritation of the anterior chamber, only antibiotic treatment was required after the operation. The intraocular pressure immediately decreased to normal levels after the operation without any further glaucoma treatment in five cases. In the other two cases reduced, but still minimally elevated, pressure was recorded. In the case of one heavily inflamed eye, which had been subjected to two operations, pain felt by the patient was relieved when the pressure was reduced. The maximum period of post-operative follow-up so far is over 10 months and the decrease of intraocular pressure has remained adequate without any additional antiglaucoma therapy. In all cases enucleation was avoided.

Glaucoma↗