Dielectric properties of a combined main-chain/side-chain liquid-crystalline polymer

The dielectric relaxation properties of a combined main-chain/side-chain liquid-crystalline polymer were investigated. It was found that the rotation of the side chain about the main chain (δ-process) is not as strongly restricted as in side-chain liquid-crystalline polymers. This is attributed to the facts that the side chain is attached to the flexible spacer within the chain backbone and that the concentration of the side chains is comparatively small. Two low-temperature relaxation processes were observed to occur in the glassy smectic and the crystalline state. They are attributed to intramolecular motions with in the mesogenic groups.     

Pathologische Myophosphorylasereaktion bei der malignen Hyperthermie

Zusammenfassung Die Myophosphorylasereaktion (MPR) zeigt bei der malignen Hyperthermie (MH) charakteristische Veränderungen, die in Minutenschnelle entstehen: 1.) eine allgemein stark abgeschwächte Reaktion, 2.) zahlreiche negativ reagierende Fasern, 3.) häufig fleck- und/oder streifenförmig abgeschwächt oder negativ reagierende und streifenförmig verstärkt reagierende Faserabschnitte mit relativ engen Sarkomerenabständen (Zeichen der Hyperkontraktion). Diese morphologischen Befunde mit den kennzeichnenden Streifenfasern sind offenbar für das MH-Syndrom spezifisch! Wichtig ist, daß die derart veränderten Muskelfasern in der Regel bei den anderen Färbungen und Reaktionen unauffällig sind.Wir sahen diese pathologische MPR bei 5 verstorbenen Patienten, einmal unabhängig von einer Anästhesie nach einem Marsch, und bei 19 Schweinen, davon 18mal nach dem Halothantest und einmal bei einem Versuchstier mit gesicherter MH. Sie fehlte bei Schweinen mit negativer Halothanreaktivität und vor dem Halothantest und bei vielen, sehr verschiedenen gesunden und kranken Kontroll- und Vergleichsfällen aus dem bioptischen und autoptischen Untersuchungsgut. Die MPR erlaubt den sicheren Nachweis einer inszenierten oder abgelaufenen MH und damit eine Aufklärung rätselhafter oder scheinbar klarer Todesfälle während oder nach der Narkose oder allgemein nach Streß (human stress syndrome), von denen sicher viele der klinischen Aufmerksamkeit und den üblichen morphologischen Untersuchungsmethoden entgehen. Sie ist nicht geeignet, potentielle Opfer zu erkennen.Mit Unterstützung des Ministeriums f. Gesundheitswesen (HFR Schwangerschaft und frühkindliche Entwicklung, FR Genetische Defekte). Auszugsweise vorgetragen auf dem IV. Internationalen Myologie-Kolloquium in Jena 1984     

Risk Factors and Management of Leukopenia After Kidney Transplantation: A Single-Center Experience

BackgroundLeukopenia is a common complication after kidney transplantation. The etiology is multifactorial, with medication adverse effects and cytomegalovirus infection as main causes. Optimal strategies to prevent or treat posttransplant leukopenia remain unknown. We aimed to identify risk factors for leukopenia and to investigate the benefit of switching the immunosuppressive therapy to hydrocortisone as a continuous infusion.MethodsWe retrospectively evaluated all patients with leukopenia after kidney transplantation between 2007 and 2017 at our center relative to age- and sex-matched controls.ResultsLeukopenia was associated with the degree of rejection therapy before leukopenia, the immunosuppressive therapy before transplantation, and an induction therapy with rabbit antithymocyte globulin. Patients with leukopenia exhibited increased mortality, an increased incidence of bacterial and viral infections, and more acute rejections. Switching to hydrocortisone as a continuous infusion in patients with severe leukopenia decreased the duration of leukopenia and the incidence of subsequent viral infections, especially with cytomegalovirus.ConclusionLeukopenia is a risk factor for infectious complications and mortality, and it is associated with acute rejection. Switching immunosuppressive therapy to hydrocortisone as a continuous infusion is a safe approach to reduce the duration of leukopenia and the incidence of viral infections.     

Radiologische Interventionen bei Schlaganfall

Notfall + Rettungsmedizin - In den letzten Jahren hat sich die mechanische Thrombektomie mit Stent-Retrievern als wichtiger Bestandteil der Behandlung des ischämischen Schlaganfalls etabliert....     

Stellenwert von Computertomographie und Magnetresonanztomographie bei der Diagnostik von Malignomen der Mundh?hle und des Oropharynx

Problem: There is a lack of clear criteria for the use of MR and CT in the diagnosis of head and neck cancer – some of it is even contradictory. The results of this study should lead to the establishment of more clear criteria. Patients: 165 patients suffering from head and neck tumors were subjected to a total of 463 CT and 197 MRI examinations. Results: The CT and MRI staging corresponded in 67% and 60% of the oropharynx tumors, respectively, with the clinical findings. In the case of oral cavity tumors, the clinical TNM stages were identical with CT and MRI results in 50% and 43% of cases, respectively. In the case of lymphatic node staging, the frequency of error was slightly higher using MRI, at 27%, compared with the CT rate of 22%. In the evaluation of cervical lymphatic nodes, CT proved to be more sensitive attaining 78% compared to the MRI rate of 69%. Conclusion: The results provide clear indications as to the MRI and CT examinations. Primary preoperative screening and post-therapeutic aftercare should be assessed using CT, as should lymphatic node diagnosis in the neck area. In the case of special problems such as, for example, the relevant bone and periostium infiltration, MR should be considered as a supplementary examination at a second stage.      

Influence of Fluorescent Labelling of Polystyrene Particles on Phagocytic Uptake,Surface Hydrophobicity,and Plasma Protein Adsorption

Purpose. To investigate the influence of fluorescent labelling of polystyrene particles on phagocytic uptake, surface hydrophobicity and protein adsorption. Methods. Phagocytic uptake was analysed using chemiluminescence. Hydrophobicity was quantified by adsorption measurements of a hydrophobic dye. Protein adsorption was evaluated by two-dimensional electrophoresis. Results. Commercially available fluorescently labelled particles showed marked differences when compared to unlabelled particles: phagocytic uptake and surface hydrophobicity of labelled particles were diminished. Also the plasma protein adsorption pattern was found to be different from the unlabelled particles: for example, the amount of fibrinogen adsorbed was strongly reduced on the labelled particles. On the other hand, some unknown proteins could be detected on the fluorescently marked particles. In contrast, plain polystyrene particles and labelled ones could be successfully synthesised by Paulke which did not show any considerable differences in phagocytic uptake, surface hydrophobicity and protein adsorption. Polysorbate 20 added as stabilizer to particle suspensions led to completely different behaviour of the particles: the particles showed altered protein adsorption patterns, dominated by immunoglobulins and especially by apolipoproteins. Furthermore, these particles were not phagocytized at all. Conclusions. Surface hydrophobicity and phagocytic uptake in vitro as well as the interactions with plasma proteins of commercially available polystyrene particles were strongly affected by fluorescent labelling. Particles synthesised by Paulke remained unchanged after labelling. The results show the importance of thorough surface characterization for using particles in test systems in vitro and in vivo.     

Flecked chorioretinopathy associated with Birt-Hogg-Dubé syndrome

Background: BirtHogg-Dubé's syndrome is a rare skin disease characterized by multiple trichofibromas of the skin and polyps of the intestine. Ophthalmologic manifestations associated with the syndrome have not been reported in detail. Case reports and methods: Two siblings suffering from Birt-Hogg-Dubé syndrome were examined clinically. Electrooculography and electroretinography were performed according to international standards. Color fundus photographs were taken as well as fluorescein angiograms. The two patients showed multiple perifollicular fibromas and trichodiscomas of the skin of the head. Funduscopy and fluorescein angiography revealed a flecked chorioretinopathy in one patient with progressive constriction of visual fields and severely reduced electroretinographic responses. Ophthalmoscopy in his sister showed peripheral pigmentary changes with only minor functional abnormalities. Conclusion: These findings suggest that Birt-Hogg-Dubé syndrome may be associated with a progressive flecked chorioretinopathy with constricted visual fields and that patients with the syndrome should undergo ophthalmological examination.     

Management of fibrous histiocytoma of the corneoscleral limbus: Report of a case and review of the literature

Background: Fibrous histiocytomas of the corneoscleral limbus are rare tumors. We present an additional case and review the treatment approaches in the literature. So far, only light and electron microscopic studies have been performed. We used immunohistochemical stains to further characterize the cellular composition. Methods: The excised lesion was routinely fixed and processed for light microscopy and immunohistochemical studies. For comparison, three dermal fibrous histiocytomas were also examined and processed similarly. Results: The corneolimbal tumor was mainly composed of fibroblasts and histiocytes with a large amount of interstitial collagen, arranged in a storiform pattern. Immunohistochemical stains were positive for histiocytes, fibroblasts, and a marker for mesenchymal cells. The staining pattern of the dermal lesions was similar. Conclusion: Fibrous histiocytomas of the corneolimbal region are morphologically benign, slowly growing and infiltrative tumors. Complete resection, especially of the deep margin, is suggested. The immunohistochemical staining pattern is similar to that of dermal fibrous histiocytomas, which behave in a benign manner.