Search PubMed⌕ Search

Biomedical subjects

R Steiner

Publications and source records attributed to R Steiner.

At least 19 recordsLinked to original sources
PubMed1999

IgG subclass reactivity to human cardiac myosin in cardiomyopathy patients is indicative of a Th1-like autoimmune disease.

Studies performed in mice together with the demonstration of increased levels of heart-specific autoantibodies, cytokines and cytokine receptors in sera from cardiomyopathy (CMP) patients argued for a pathogenic role of autoimmune mechanisms in CMP. This study was designed to analyse the presence of IgG anti-heart antibodies in sera from patients suffering from hypertrophic and dilatative forms of CMP as well as from patients with ischaemic heart disease and healthy individuals. Patients' sera were analysed for IgG reactivity to Western-blotted extracts prepared from human epithelial and endothelial cells, heart and skeletal muscle specimens as well as from Streptococcus pyogenes. The IgG subclass (IgG1-4) reactivity to purified human cardiac myosin was analysed by ELISA. While sera from CMP patients and healthy individuals displayed comparable IgG reactivity to a variety of human proteins, cardiac myosin represented the prominent antigen detected strongly and preferentially by sera from CMP patients. Pronounced IgG anti-cardiac myosin reactivity was frequently found in sera from patients with dilatative CMP and reduced ventricular function. ELISA analyses revealed a prominent IgG2/IgG3 anti-cardiac myosin reactivity in CMP sera, indicating a preferential Th1-like immune response. Elevated anti-cytomegalovirus, anti-enterovirus IgG titres as well as IgG reactivity to nitrocellulose-blotted S. pyogenes proteins were also frequently observed in the group of CMP patients. If further work can support the hypothesis that autoreactivity to cardiac myosin represents a pathogenic factor in CMP, specific immunomodulation of this Th1- towards a Th2-like immune response may represent a promising therapeutic strategy for CMP.

Adolescent↗
PubMed1999

Two alternatively spliced Meig1 messenger RNA species are differentially expressed in the somatic and in the germ-cell compartments of the testis.

Previous studies regarding the transcriptional pattern of the murine Meig1 gene (formally designated meg1) suggested that its transcription is restricted to germ cells at the first meiotic prophase, in both primary spermatocytes and primary oocytes. However, protein analysis revealed that certain forms of the MEIG1 protein exist in testes of early postnatal pups at stages that have no germ cells in the testis, excluding very few primitive type A spermatogonia cells. This suggested that MEIG1 expression is not confined to germ cells. In this study, we show that testicular somatic cells do, indeed, express MEIG1. This is especially evident in Leydig cells, where this protein is highly abundant. We also demonstrate that alternatively spliced mRNAs of Meig1 are differentially transcribed in the germ cell and the somatic compartments of the testis. There is a very low level of somatic transcript, whether labile or transcriptionally regulated, in contrast to the abundant MEIG1 protein in the somatic cells. This implies that the somatic transcript is very efficiently translated and reconfirms that protein levels do not necessarily reflect transcript abundancy. Structural features of the Meig1 transcript that would be expected to inhibit translation are discussed in light of the efficient translation of this RNA species.

Alternative Splicing↗
PubMed1998

[Intracanalicular trabeculostomy--a new approach to glaucoma surgery].

BACKGROUND: A new "ab externo" technique for glaucoma trabecular surgery creating multiple perforations of the trabeculum to improve outflow facility was tested. MATERIAL AND METHOD: In order to perform a draining canal to the anterior chamber, a quartz fiber (phi: 300 microns) with a side-firing tip, coupled to an Er:YAG laser (2.94 microns), was inserted into Schlemm's canal of an enucleated human eye. RESULTS: Eight pulses of 8 mJ each were sufficient to perforate the trabecular meshwork. Histologic analysis showed a rippled canal with 50 microns average diameter and a surrounding necrosis zone of 15-35 microns. CONCLUSIONS: The Er:YAG laser trabeculostomy, in conjunction with special fibers, shows promise as a new "ab externo" technique for minimally invasive therapy of open angle glaucoma.

Endoscopes↗
PubMed1998

Selective examination of plasma membrane-associated photosensitizers using total internal reflection fluorescence spectroscopy: correlation between photobleaching and photodynamic efficacy of protoporphyrin IX.

Fluorescence spectra, fluorescence decay kinetics, photobleaching kinetics and photodynamic efficacy of protoporphyrin IX (PP) were investigated in endothelial cells in vitro after different incubation times. Fluorescence spectra and photobleaching kinetics were determined during total internal reflection (TIR) illumination or epi-illumination. Because penetration depth of the excitation light during TIR illumination was limited to about 100 nm, plasma membrane-associated PP was almost selectively examined. Spectra obtained by TIR fluorescence spectroscopy (FS) showed a very low background, whereas spectra obtained by epi-illumination exhibited considerable background by autofluorescence and scattered light. For photobleaching kinetics during TIR illumination after 1 h or 24 h incubation, a biexponential fluorescence decrease was observed with a rapidly and a slowly bleaching portion. After 1 h incubation, the rapidly bleaching portion was the predominant fraction, whereas after 24 h incubation comparable relative amounts of the rapidly and slowly bleaching portion were determined. The rapidly and slowly bleaching portion were assigned to PP monomers and aggregated species in close vicinity to the plasma membrane. Fluorescence decay measurements after epi-illumination support the decrease of PP monomers within the whole cell with increasing incubation time. In contrast to TIR illumination, photobleaching of PP during epi-illumination was characterized by slow monoexponential fluorescence decrease after 1 h or 24 h incubation. Photodynamic efficacy of PP using epi-illumination was found to depend strongly on incubation time. Considerable cell inactivation was determined for short incubation times (1 h or 3 h), whereas photodynamic efficacy was diminished for longer incubation times. Reduced photodynamic efficacy after long incubation times was assigned to the lower amount of photodynamically active monomers determined close to the plasma membrane as well as within the whole cell. In conclusion, TIRFS measurements are suggested to be an appropriate tool for the examination of the plasma membrane-associated photosensitizer fraction in living cells.

Animals↗
PubMed1997

Thermo-controlled device for inducing deep coagulation in the liver with the Nd:YAG laser.

BACKGROUND AND OBJECTIVE: To increase the effectiveness of laser-induced interstitial thermotherapy (LITT), a new thermo-controlled application system for minimal invasive intervention was designed. Our system consists of a laser applicator of 2.5 mm in diameter, insertion equipment, and a Nd:YAG-laser source. STUDY DESIGN/MATERIALS AND METHODS: A cylindrical light emitting fiber (1-6 cm in length) was placed in the center of the applicator. The surrounding tissue was irradiated through a Duran window at the distal end of the applicator. The power of the laser source was controlled dynamically by thermosensors in a water-cooling system of the laser applicator. The temperature at the surface of the Duran window was kept constant at approximately 60 degrees C, without charring the surrounding tissue. RESULTS/CONCLUSION: We obtained homogeneous coagulation zones. In in vitro experiments with pig livers, we reached ellipsoid coagulation volumes of 3 and 5 cm in diameter within 10 minutes, corresponding to a volume of approximately 25 cm3.

Animals↗
PubMed1997

High-level expression and purification of the major birch pollen allergen, Bet v 1.

Bet v 1, the single major allergen from birch pollen, shares IgE epitopes with all major tree pollen allergens from closely related species such as alder, hazel, hornbeam, beech, and European chestnut. Because of high sequence homologies among these allergens and the well-studied cross-reactivities on B cell epitopes, Bet v 1 is a representative model protein which can be used for in vitro studies. The cDNA coding for Bet v 1, the single major allergen from birch pollen, was cloned into the T7-based Escherichia coli expression system pMW 175/BL21(DE3) and synthesized as a nonfusion protein. In contrast to other E. coli systems (e.g., pKK233-2/JM105), this system produces high levels of readily extractable proteins corresponding to 5-10% of E. coli total protein, the percentage varying with culture conditions. The overall yield was 8-10 mg of purified recombinant protein per liter of culture medium. The recombinant allergen was purified by several steps, including ion-exchange and hydrophobic interaction chromatography. The purified recombinant allergen showed identical immunological properties with the respective natural counterpart. The use of recombinant allergens of high purity is expected to result in more accurate diagnostic procedures, but possibly also in a superior immunotherapy of Type I allergic diseases when compared with methods using crude allergen extracts containing various amounts of allergen concentrations.

Allergens↗
PubMed1997

[Dynamic interstitial laser application for therapy of secondary liver tumors. An animal experiment study].

Laser-induced interstitial thermotherapy (LITT) is a promising method of treating different types of tumors. To increase the effectiveness of LITT, a new thermo-controlled application system for minimal invasive intervention was designed. This laser system consists of a laser applicator 3 mm in diameter, insertion equipment and an Nd:YAG laser source. The power of the laser source is controlled dynamically by thermosensors in a water-cooling system of the laser applicator. In in vivo experiments in five pigs, within 10 min we found homogeneous coagulation regions in the liver that were of 3 cm and 5 cm in diameter. Via ultrasound we observed in real time the increasing coagulation zone that appeared as a hyperechogenic halo. However, due to perifocal edema, the real coagulation area was smaller than detected by ultrasound. Macroscopically and microscopically, the coagulation zones showed well-demarcated borders of the coagulation lesions, and the surrounding tissue appeared vital. The reparative reaction after irradiation was early fibrosis. In the course of 4 weeks, the surrounding scar capsule, containing fibrocytes, biliary ductules and collagen fibers enlarged. As a result, the coagulation necrosis became more and more fragmented between collagen fibers and was largely resorbed. The absence of complications in our animal experiments suggest that the technique of thermo-controlled laser light application is safe and useful in therapy for metastases that are not resectable.

Animals↗
PubMed1997

[Modified radiation administration in Er:YAG laser ab externo sclerostomy].

BACKGROUND: Ab externo sclerostomy enables the restrained aqueous humour drain via a microgram wide corneoscleral canal into the subconjunctival space being an alternative surgical method in glaucoma therapy. The tissue ablative infrared laser radiation (2.94 microgram) was applied until now via a quartz fiber manually pushed forward in permanent tissue contact. Our aim was the development of a new applicator tip without manual feed in order to achieve a reduction in times for construction and maintenance of the former tip as well as in the risk of an infection and mechanical damage of intraocular structures. MATERIAL AND METHOD: In pig eye experiments, the laser parameters were varied in histological and scanning electron microscopic evaluation (pulse energy: 10-60 mJ, repetition rate: 5-17.5 Hz, combinations of constant power: 200 mW). Their influence on the canal shape and the morphology of the internal ostium has been proven in special tests. RESULTS: The new development of the applicator tip (core diameter: 550 microgram) enables a conical profile of the beam (diameter 500-150 microgram) within a distance of 2-3 mm, now without pushing the fiber forward ("fixed fiber"). Smooth canal surfaces, a small homogeneous necrosis zone (25 microgram) and only few tissue ruptures have been seen histologically and on SEM. The correlations of ablation rates/-speed as well as canal characteristics are more significant to energy densities than to repetition rates. First clinical application was technically successful. CONCLUSIONS: The new applicator tip optimizes the method of Er: YAG-laser ab externo sclerostomy from the technical and surgical point of view.

Animals↗
PubMed1997

Energy transfer spectroscopy for measuring mitochondrial metabolism in living cells.

Microscopic energy transfer spectroscopy was established using mixed solutions of reduced nicotinamide adenine dinucleotide (NADH) and the mitochondrial marker rhodamine 123 (R123). This method was applied to probe mitochondrial malfunction of cultivated endothelial cells from calf aorta incubated with various inhibitors of specific enzyme complexes of the respiratory chain. Autofluorescence of the coenzyme NADH as well as energy transfer efficacy from excited NADH molecules (energy donor) to R123 (energy acceptor) were measured by time-gated fluorescence spectroscopy. Because intermolecular distances in the nanometer range are required for radiationless energy transfer, this method is suitable to probe selectively mitochondrial NADH. Autofluorescence of endothelial cells usually exhibited a weak increase after specific inhibition of enzyme complexes of the respiratory chain. In contrast, pronounced and statistically significant changes of energy transfer efficacy were observed after inhibition of the same enzyme complexes. Detection of NADH and R123 in different nanosecond time gates following the exciting laser pulses enhances the selectivity and improves quantification of fluorescence measurements. Therefore, time-gated energy transfer spectroscopy is suggested to be an appropriate tool for probing mitochondrial malfunction.

Animals↗
PubMed1997

[Cervical pregnancy. A gynecologic-obstetric emergency situation].

The cervical pregnancy is defined as the implantation of the blastocyst into the cervical canal. The characteristic clinical sign is a severe asymptomatic uterine bleeding in early pregnancy or during curettage. Prior to 1978, correct preoperative diagnosis was rare and in almost all cases a hysterectomy was performed. Today, transvaginal sonography allows early diagnosis, and conservative treatment (two-time treatment: first treatment with systemic or intraamniotic methotrexate, secondly with curettage or ligature of the uterine arteries) improves the prospects of fertility.

Abortion, Induced↗
PubMed1996

Are coping strategies related to disease outcome in early breast cancer?

A consecutive series of 107 women with early breast cancer were investigated for coping strategies and disease outcome 5 to 6 years after primary surgical treatment (mastectomy or lumpectomy). Coping was assessed several times during a 3-year investigation period by the Zurich and Freiburg Questionnaires of Coping with Illness (ZQCI, FQCI). Data analysis revealed no significant correlations between coping strategies and the target variable "death from breast cancer". However, significant relations were found between postsurgical tumour size (p < or = 0.01), positive histological node status (p < or = 0.01) and death from breast cancer. The results of a discriminant analysis also indicated that somatic parameters are more important for the course of breast cancer disease than psychological aspects of coping. The role of psychosocial variables for the outcome of cancer disease remains unclear and further studies in this field are necessary.

Adaptation, Psychological↗
PubMed1996

Dynamic fluorescence changes during photodynamic therapy in vivo and in vitro of hydrophilic A1(III) phthalocyanine tetrasulphonate and lipophilic Zn(II) phthalocyanine administered in liposomes.

The fluorescence emission of hydrophilic tetrasulphonated aluminium phthalocyanine (AlPcS4) and hydrophobic zinc phthalocyanine (ZnPc), bound to the membrane of liposomes, was investigated in vivo in an appropriate tumour model of the rat bladder and in RR 1022 epithelial cells of the rat. The sensitizers were administered systemically to the rats and photodynamic therapy (PDT) was performed 24 h later. During PDT treatment, the fluorescence was measured every 30 s. The fluorescence was excited with 633 nm light from an HeNe laser and the fluorescence spectra were detected with an optical multichannel analyser system. PDT was performed for both sensitizers using 672 nm light from an Ar+ dye laser. The fluorescence changes during PDT were significantly different for the two phthalocyanines. For AlPcS4, an initial fluorescence intensity increase, followed by subsequent photobleaching, was observed. In contrast, ZnPc fluorescence showed an exponential decrease and no increase at the start of treatment. Tumour necrosis 24 h after PDT was significant only for ZnPc. RR 1022 cells incubated for 24 h with AlPcS4 revealed a granular fluorescence pattern, whereas ZnPc was localized diffusely in the cytoplasm of the cells. In agreement with the in vivo measurements, subcellular relocalization and a fluorescence intensity increase were detected exclusively in the case of AlPcS4. Morphological changes at this time were significant only for ZnPc. The subcellular localization and fluorescence kinetics were obtained using a confocal laser scanning microscope.

Animals↗
PubMed1996

[Concomitant injuries after upper ankle joint dislocations].

Functional treatment with the Air Stirrup Ankle Brace recommended by C. N. Stover in 1979 can reduce pathological inversion of the ankle joint. In our retrospective study of 109 patients treated by this kind of ankle brace we found 96 patients (88%) with excellent results. Only 13 patients (12%) reported moderate to good results. To detect and characterize their painful conditions of ankles we did a clinical, radiological and MRI-Investigation. In only 2 cases we found a moderate instability after clinical investigation, anterior stress roentgenogram and talar tilt. By using the MRI-investigation 1.0 Tesla with a 512 x 360 Matrix we could find 10 cases with osteochondral lesions of the ankle. In 7 cases there was separated ossicle in the fibulotalar joint, in 1 case we detected a fracture of the processus anterior tali, in another case we could see a posttraumatic lesion of the talus and calcaneus with bone bruise and at least one osteochondral fracture of the distal tibia. The capability of the MRI to detect particularly osteo-chondral lesions of the talus and the tibiofibular joint was shown in 10 of 13 cases. Therefore we recommend to do an MRI-investigation on all patients after ankle sprain if there are painful conditions within the ankle after conservative treatment.

Adult↗
PubMed1996

[Ab externo sclerostomy with the Er:YAG laser: report of outcome after 2 years].

OBJECT: Results over a period of 24 months of performing the Er:YAG laser ab externo sclerostomy. MATERIAL AND METHODS: The procedure was performed 81 times (chronic glaucoma with open angle (n = 55) and narrow angle (n = 15), 6 secondary glaucoma, 4 pigment glaucoma, 1 normal pressure glaucoma) in 74 eyes of 64 patients at the age of 70 +/- 10 years without any peribulbar anesthesia. The pulse energy was 11 mJ with a repetition rate of 7 Hz. Antimetabolites were not applicated. Success was defined as an IOP of less than 22 mm Hg or a decrease of at least 30%, with or without anti-glaucoma medication. RESULTS: The mean IOP of all cases decreased from preoperatively 28 +/- 8.1 mm Hg (Success group: 26.7 +/- 7.3 mm Hg) to 15 +/- 8.4 mm Hg (Success group: 14.6 +/- 7.8 mm Hg) on the first postoperative day. The success rate was about 50% within the period of two weeks to six months and decreased to about 15% in the 24th month. Complications were iris incarceration/synechia (n = 33), hypotony (n = 36) with consequent choroidal detachment (n = 8), hyphema (n = 19) and more pronounced inflammation symptoms (n = 10). In most cases, the early postoperative outflow failure is caused by iris incarceration into the internal ostium. The scarring tendency of the episcleral tissue leads to closure of the external ostium after months. Resurgery was necessary in 26 cases. CONCLUSIONS: Further efforts should be directed to maintain the intact corneoscleral morphology of the canal, created by an optimized method of the surgical technique. The application of antimetabolites in correct dosage or the implantation of modified silicon draining systems would be helpful.

Aged↗
PubMed1996

Regeneration processes in rabbit endometrium: a photodynamic therapy model.

The origin and process of regeneration in rabbit endometrium was evaluated following photodynamic epithelial destruction using topically applied aminolevulinic acid (ALA). Selective destruction of endometrial epithelium was performed using photodynamic therapy (PDT). ALA was diluted to 200 mg/ml dextran 70 shortly prior to administration. A volume of 1.2 ml was injected into the left uterus. Intrauterine illumination (wavelength 630 nm, light dose 40-80 J/cm2) was performed 3 h after drug administration. Tissue morphology was evaluated by light and scanning electron microscopy 1, 3, 7 and 28 days post-treatment (three animals at each time-point). Regeneration of the endometrium following epithelial ablation by PDT was fully activated after 24 h and was completed after 72 h. Endometrial surface generation occurred by proliferation, originating primarily in deeper regions of the glands. Findings from our morphological follow-up study support the origin of endometrial regeneration being mainly from undifferentiated stem cells and residual glandular epithelium.

Aminolevulinic Acid↗
PubMed1996

Immunoglobulin E response to human proteins in atopic patients.

The demonstration that human IgE recognizes both exogenous allergens and structurally related human proteins has led to the hypothesis that IgE autoreactivity may be a pathogenic factor in atopic diseases. To determine the frequency of occurrence as well as the disease specificity of this phenomenon, we tested sera from patients with atopic diseases and, for control purposes, from persons with immunologically mediated disorders for serum IgE reactivity with nitrocellulose-blotted human proteins. We found that 12 of 20 sera from atopic patients with pronounced skin lesions contained Western blot-detectable IgE antibodies. Patients suffering predominantly from allergic rhinoconjunctivitis as well as control individuals failed to display serum IgE autoreactivity, but occasionally exhibited elevated serum IgE levels. The molecular weights of the IgE-defined autoantigens ranged predominantly from 10 to 100 kDa. Whereas some of these were expressed in only certain cell types, others were detected in histogenetically different cells. Our results suggest that IgE autoimmunity occurs frequently in atopic dermatitis patients and may be of pathogenic relevance for the chronicity of skin manifestations typical of this disease.

Antibody Specificity↗