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Biomedical subjects

T Jaeger

Publications and source records attributed to T Jaeger.

At least 19 recordsLinked to original sources
PubMed2006

[High-dose rate brachytherapy for high-risk prostate cancer].

To estimate disease-free survival it is necessary to allocate patients into tumor risk groups: locally advanced prostate carcinoma with extracapsular spread or localized prostate carcinoma of tumor stage T2c or one of the risk factors PSA >20 or Gleason > or =8 apply for the high-risk group. Intermediate-risk carcinomas are those belonging to tumor stage T2b or with PSA >10-20 or Gleason 7. Particularly for patients with intermediate and high-risk disease early PSA relapse is of major interest. This phenomenon could be a consequence of current inadequate imaging of lymph node or bone metastasis or as a consequence subclinical metastatic spread remains undetectable during radical treatment. However, tumor biology itself could lead to the progression of the disease in the high-risk group. As a consequence, risk-adapted therapy is very important in these cases. The applied radiation dose plays an important role in radiotherapy. Several publications have shown that the biochemical relapse correlates with the generally accepted risk factors and the radiation dose. Regarding this, high-quality treatment planning and HDR brachytherapy combined with EBRT (external beam radiation therapy) leads to good treatment results in selected groups. So far in our own experience, HDR brachytherapy in combination with EBRT is a successful form of treatment with few acute and late side effects in the first 42 patients examined. First results concerning to PSA relapse-free time, quality of life, miction, and erectile function are promising.

Biomarkers, Tumor↗
PubMed2003

Thiol-dependent peroxidases care little about homology-based assignments of function.

Thiol-dependent peroxidase systems are reviewed with special emphasis on their potential use as drug targets. The basic catalytic mechanism of the two major thiol-peroxidase families, the glutathione peroxidases and the peroxiredoxins, are reasonably well understood. Sequence-based predictions of substrate specificities are still unsatisfactory. GPx-type enzymes are not generally specific for GSH but may specifically react with CXXC motifs as present in thioredoxins or tryparedoxins. Inversely, the peroxiredoxin family that was believed to be specific for CXXC-type proteins, also comprises glutathione peroxidases. Since structure-based predictions of function are also limited by small data bases, the increasing number of sequences emerging from genome projects require enzymatic characterization and genetic proof of relevance before they can be classified as drug targets.

Animals↗
PubMed2001

Similarity and lightness effects in Ebbinghaus illusion created by keyboard characters.

36 observers judged the size of a central S in variants of the Ebbinghaus figure having contextual Ss, $s, or Hs. When the figures were composed of similarly shaped elements, underestimation of the central S was obtained. Manipulations of lightness indicated that these underestimations were strongest for figures with gray contextual characters and a black central S and weakest for figures with black contextual characters and a gray central S. All black or all gray figures produced intermediate illusions. The data are consistent with Choplin and Medin's 1999 claim that figural properties rather than semantic similarity influences size contrast and further show that the visual processes underlying size contrast include interactions of contours.

Adolescent↗
PubMed1997

Enhancement of neutrophil-mediated killing of Plasmodium falciparum asexual blood forms by fatty acids: importance of fatty acid structure.

Effects of fatty acids on human neutrophil-mediated killing of Plasmodium falciparum asexual blood forms were investigated by using a quantitative radiometric assay. The results showed that the antiparasitic activity of neutrophils can be greatly increased (>threefold) by short-term treatment with fatty acids with 20 to 24 carbon atoms and at least three double bonds. In particular, the n-3 polyenoic fatty acids, eicosapentaenoic and docosahexaenoic acids, and the n-6 fatty acid, arachidonic acid, significantly enhanced neutrophil antiparasitic activity. This effect was >1.5-fold higher than that induced by an optical concentration of the known agonist cytokine tumor necrosis factor alpha (TNF-alpha). At suboptimal concentrations, the combination of arachidonic acid and TNF-alpha caused a synergistic increase in neutrophil-mediated parasite killing. The fatty acid-induced effect was independent of the availability of serum opsonins but dependent on the structure of the fatty acids. The length of the carbon chain, degree of unsaturation, and availability of a free carboxyl group were important determinants of fatty acid activity. The fatty acids which increased neutrophil-mediated killing primed the enhanced superoxide radical generation of neutrophils in response to P. falciparum as detected by chemiluminescence. Scavengers of oxygen radicals significantly reduced the fatty acid-enhanced parasite killing, but cyclooxygenase and lipoxygenase inhibitors had no effect. These findings have identified a new class of immunoenhancers that could be exploited to increase resistance against Plasmodium species.

Adjuvants, Immunologic↗
PubMed1997

The role of complement, antibody, and tumor necrosis factor alpha in the killing of Plasmodium falciparum by the monocytic cell line THP-1.

Killing of Plasmodium falciparum blood forms by the differentiated human myelomonocytic THP-1Mo cell line was studied by a radiometric assay. Results showed that parasite killing was promoted by complement, antimalarial antibody, and the cytokines tumor necrosis factor alpha and gamma interferon. Differentiated THP-1Mo appears to be a useful monocytic cell line for the study of mechanisms of immunity to Plasmodium.

Animals↗
PubMed1996

GM-CSF-induced priming of human neutrophils for enhanced phagocytosis and killing of asexual blood stages of Plasmodium falciparum: synergistic effects of GM-CSF and TNF.

Granulocyte macrophage-colony stimulation factor (GM-CSF), which is a haematopoietic cytokine generated by activated T lymphocytes and macrophages during infection, was investigated for its effects on human neutrophil-mediated killing of asexual blood forms of Plasmodium falciparum. Pretreatment of neutrophils with human recombinant-GM-CSF markedly increased the parasite killing (measured by a radiometric assay), in the presence of normal serum (containing complement), immune serum (IS), purified IgG (from IS) or heat inactivated IS. GM-CSF pretreatment also enhanced phagocytosis of the parasite by neutrophils and the expression of CR3, Fc gamma RII and Fc gamma RIII receptors. Treatment of neutrophils with a combination of GM-CSF and TNF resulted in a synergistic increase in phagocytosis and killing of the parasite. The findings suggest that GM-CSF is likely to form part of the cytokine network responsible for regulating the antiparasitic activity of the neutrophil in malaria.

Animals↗
PubMed1994

Note on the ontogeny of assimilative illusions: a reply to Pressey (1987).

It is argued that a previous study showing the parallel lines illusion is stronger in adulthood than in adolescence or old age is methodologically sound. Further, this finding does not necessitate a defense of assimilation theory based on epistemology that links the phenomenal properties of illusions to the techniques of measurement. Rather, it is suggested that Pressey's 1974 and 1987 hypothesis that all illusions of assimilation decline from childhood to adulthood mistakenly extends the decrement into adulthood when in fact the decrement occurs only between the ages of 6 and 10 years.

Adolescent↗
PubMed1993

Contour lightness and separation effects in the Ebbinghaus illusion.

For 48 observers, the central circle of Ebbinghaus figures appeared smaller as the separation between it and the contextual circles increased. Lightness of the contours only affected the illusion when the contextual circles were large and located close to the central circle. An explanation incorporating size contrast and attraction between contours was offered.

Contrast Sensitivity↗
PubMed1992

Effects of cytokines, complement, and antibody on the neutrophil respiratory burst and phagocytic response to Plasmodium falciparum merozoites.

The interaction between Plasmodium falciparum merozoites and human neutrophils, as well as the role of cytokines, complement, and antimalarial antibody on this interaction, was examined in vitro by measuring luminol-dependent chemiluminescence and phagocytosis. Merozoites, in the presence of heat-inactivated (56 degrees C/30 min) normal serum, had very little effect on the neutrophil chemiluminescence. This response was significantly enhanced by the addition of normal serum (containing normal complement activity). In the presence of serum or plasma containing anti-P. falciparum antibodies (IS) with no detectable complement activity, the merozoites induced a marked response characterized by an increase in initial peak rate of chemiluminescence and a sustained increased rate of chemiluminescence. However, this response was not further increased if IS containing complement activity was used. Pretreatment of neutrophils with either tumor necrosis factor alpha, lymphotoxin, or gamma interferon significantly increased the neutrophil response to IS-treated merozoites, reflected in an increased initial peak rate and sustained increased rate of chemiluminescence. The effects of cytokine treatment of neutrophils and IS opsonization of merozoites were synergistic. In association with the changes in the chemiluminescence responses, IS was shown to promote phagocytosis of merozoites by neutrophils, and this event was further increased by treating neutrophils with the cytokines. The results emphasize the importance of antibody and cytokines in neutrophil-mediated damage of P. falciparum merozoites.

Animals↗
PubMed1991

[CPM treatment of the shoulder joint].

Since Salter's results about experimental continuous passive motion (CPM) there are remarkable, generally positive experiences on CPM-treatment of the knee-joint. Now CPM-experiences on shoulder joints are described based on data from 150 patients during the last six years. Three types of motorized CPM-machines are presented for the treatment of the shoulder joint. At the present time they are components of the so-called "Artromot-System." Indications and applications of the CPM-devices are described. Patients are accepting the new way of treatment promptly, because they could apply the devices during the early postoperative period for hours in a selected range of motion, causing no pain. The duration of the CPM-treatment should be two to four hours a day. As shown by Salter's experimental studies the continuous passive motion enhances the metabolism of a joint, improves the resorption of effusions, and may prevent joint stiffness as well as secondary arthrosis. CPM-treatment can especially be prolonged for outpatients; thus CPM treatment can contribute to shorten the hospital stay and the time of treatment in general showing an economic factor.

Humans↗
PubMed1990

[Arthrolysis of the knee joint].

This publication consists of two parts, the first of which is concerned with the definition of arthrolysis as a mere soft tissue procedure. This is delineated from arthroplasty. In the second part, arthrolysis results are presented. Three different means of treatment are possible for knee joint stiffness: manual joint mobilization under anaesthesia, arthroscopic operation, and "open" arthrolysis. The authors concentrate on the third type of treatment because of the great amount of long-term experience they have made. In the majority of cases knee joint stiffness is caused by immobilization and posttraumatic and postoperative effects on the joint itself or in the area of the joint. Morphological findings are intraarticular adhesions in the recessus, as well as between the joint surfaces, retraction of the capsular-ligament system, and extra-articularly located impediments caused by shrinkage and scars in the muscles, tendons, and sliding laminas of the soft tissue. Open arthrolysis is indicated after failure of conservative treatment and in cases of severe stiffness of the knee joint. For operative arthrolysis many requirements must be met, which are specified in detail. The preoperative information about the treatment given to the patient is of particular interest. The operative methods, including postoperative management, are described only briefly, because the presentation of the results is the main purpose of this paper. Eighty-five patients (94%) who underwent open arthrolysis were personally examined. Information about the other patients was obtained from medical records such as the examination at discharge or the last presentation in the outpatient clinic. The average follow-up time was 5 years and 4 months ranging from 6 months to 14.25 years. The results are differentiated in many respects whereas the so-called relative improvement of joint mobility following an operation is of main interest. Well-defined criteria have been published and were applied. The results are listed according to the severity of joint stiffness. Four grades of joint stiffness are created, ranging from grade IV, the most severe form with a preoperative maximum of joint mobility of 30 degrees, to grade I with a maximum of 90 degrees joint mobility. In all, operative procedures led to an improvement in nearly 100% compared to the preoperative findings. The results are presented in relation to age, operative methods, previous operations, and different stages during the follow-up.

Adult↗
PubMed1987

The type I/type II perceptual dichotomy: a reanalysis for the illusions of extent.

The categorization of geometrical illusions of extent as Type I or Type II phenomena based on variation in magnitude with age is critically examined. Methodological shortcomings and the failure of contemporary findings to show matching age trends for components of a single illusion are presented as factors undermining the usefulness of this perceptual dichotomy. Finally, it is shown that a new Type I/Type II dichotomy based on changes in perceived size rather than amount of illusion indicates a developmental commonality among most of the illusions of extent.

Adolescent↗
PubMed1986

Life-span ontogeny of the parallel-lines illusion.

The magnitude of two assimilative and one contrastive version of the parallel-lines illusion was measured using 72 observers whose ages ranged in years from the teens to the seventies. Only the overestimated assimilative illusion varied significantly with age, producing smaller misestimations in both youth and old age and a maximal distortion in the 50s. This quadratic trend duplicated the adult-age course of the overestimated Müller-Lyer illusion thereby reinforcing the belief that the two are kindred visual anomalies. As with the Müller-Lyer, the ontogeny of the parallel-lines illusion is best explained by age-induced changes in the vigor of contour interactions.

Adolescent↗
PubMed1985

Contextual effects in the parallel lines illusion: some implications for assimilation theory.

32 undergraduates participated in each of two experiments designed to determine how structural manipulations of the parallel lines figure affect the resulting illusion. Collectively and for the range of figures studied, the data show progressive elongations of the contextual lines of the illusion figure first increase, then decrease, the apparent length of the judged line; the misestimation of the length of the judged line diminishes as the separation between it and shorter contextual lines increases; and variations in contour lightness significantly affect the illusion when the contextual lines are shorter than and at any distance from the judged line or when the contextual lines are slightly longer than and at an intermediate distance from the judged line. These data indicate that size-assimilation, as well as size-contrast processes, contributes to the parallel lines illusion and that the assimilation process must be mediated by both sensory and cognitive activity in the visual system.

Adolescent↗
PubMed1981

Assimilation and contrast in the parallel lines illusion?

Judgments of 40 undergraduates indicated that the assimilative character of the parallel lines illusion was destroyed at large values of both context line length and separation of context and center line variables. Accommodation of a portion of these results requires a modification of Brigner's (1977) theory of perception of illusory extent.

Discrimination Learning↗