Thoracoscopic wedge resection

Summary Thoracoscopic surgery is decidedly expanded by the ability to perform pulmonary wedge resections of the lung by using the Endo-GIA-stapler. In addition to thoracoscopic biopsies, since July 1991 we have carried out wedge resections in 12 patients suffering from spontaneous pneumothorax (nine) or peripheral bronchial carcinoma (three). Postoperatively one air fistula persisted over 9 days. The chest tube was removed within 48 h in all other patients. There was no other major complication. The postoperative hospitalization period lasted 4.6 days (1–9 days). Operating time was 44 min (30–70 min). The benefit for the patient consists in the little-impaired breathing mechanics, the short hospital stay, and the favorable cosmetic result.     

Radiologic long-term results after cervical vertebral interbody fusion with Polymethyl Methacrylat (PMMA)

Long-term results of cervical interbody fusion with PMMA were evaluated in a retrospective study. X-ray films of 83 patients were obtainable. Post-operative follow-up in this series was between 15 and 20 years. The results show that PMMA is engrafted after about 2 years. Stable vertebral interbody fusion is obtained in about 90% of cases. Development of malignoma was not observed. Resorptive bone alterations, which can be seen in about 2% of cases one to two years after operation are shown not to be progressive. This process heals and stable fusion develops.     

Peripheral clonal deletion of antiviral memory CD8+ T cells

Antiviral cytotoxic memory CD8⁺ T cells adoptively transferred to mice which are persistently infected with lymphocytic choriomeningitis virus WE or DOCILE initially proliferated extensively; they either caused the death of the recipient or, alternatively, disappeared within a few days. Apparently, the complete and coordinated induction and stimulation by widely distributed viral antigen caused these memory T cells to die before virus had been eliminated from the host. Thus memory T cells are as susceptible to peripheral exhaustion/deletion as unprimed T cells. These results indicate possible limitations of exclusively CD8⁺ T cell-mediated adoptive immunotherapy against viral infections or tumors.     

TNFα Inhibits Schwann Cell Proliferation, Connexin46 Expression, and Gap Junctional Communication

Schwann cell responses to nerve injury are stimulated, in part, by inflammatory cytokines. This study compares changes in the phenotype of cultured Schwann cells after exposure to the cytokine tumor necrosis factor (TNF)-α or the mitogen neu differentiation factor (NDF)-β. TNFα inhibited proliferation in a dose-dependent manner without altering Schwann cell survival. TNFα also reduced both gap junctional conductance and Lucifer yellow dye coupling between Schwann cells. Moreover, both P₀and glial fibrillary acidic protein (GFAP) immunoreactivity were reduced. By contrast, NDFβ initially had little effect on cell division although it reduced junctional coupling within 8 h. However, by 48 h, NDFβ stimulated proliferation with a concomitant increase in coupling. Dividing Schwann cells (BrdU⁺) were preferentially dye coupled compared to nondividing cells, indicating an association between proliferation and coupling. Moreover, cultured Schwann cells expressed connexin46 mRNA and protein, and changes in the levels of the protein correlated with the degree of proliferation and coupling. The data thus provide evidence for cytokine-induced modulation of Schwann cell antigenic phenotype, proliferation, and gap junction properties. These observations suggest that enhanced gap junctional communication among Schwann cells after nerve injury could help to coordinate cellular responses to the injury, and that TNFα may be a signal which terminates proliferation as well as junctional communication.     

Zwei Kammern für die Mikroskopie und Mikrophotometrie vitaler Zellen

Zusammenfassung Es werden zwei Kammern zur mikroskopischen Beobachtung und mikrophotometrischen Untersuchung von lebenden Zellen beschrieben. Mit ihrer Hilfe ist es möglich. Zellen ohne Schädigung mechanisch so zu stabilisiren, dasß sie bis zu Stunden an derselben Stelle liegen bleiben.In der Einstromkammer liegen die Zellen in einlagiger Schicht zwischen einem Deckglas und einer licht- und gasdurchlässigen Folie, die durch Adhäsion festgehalten wird. Der an die Folie angrenzende Raum kann mit gewünschten Gasgemischen durchströmt werden.In der Zweistromkammer liegen die Zellen zwischen zwei lichtdurchlässigen Folien, von denen die eine Gase, die andere auch Flüssigkeiten und gelöste Substanzen durchtreten läßt. Der an die flüssigkeitsdurchlässige Folie angrenzende Raum kann mit gewünschten Lösungen, der andere gleichzeitig mit Gasgemischen beströmt werden. Die Funktionsweise der Zweistromkammer wird am Beispiel der Formänderung von Erythrocyten bei Beströmen mit Lösungen verschiedenen osmotischen Druckes demonstriert. Beide Kammern eignen sich zur Vital-Mikroskopie und Photometrie von einzelnen Zellen, insbesondere Blutzellen und Gewebeschnitten.     

Uncertainties − discrepancies in immunology

Summary: The many immunological observations and results from in-vitro or in-vivo experiments vary, and their interpretations differ enormously. A major problem is that within a normal distribution of biological phenomena, which are measurable with many methods, virtually anything is possible. Within a coevolutionary context, the definition of biologically relevant thresholds is an important key to improve our understanding of weaknesses and strengths of the immune system. This review is a personal view, comparing textbook rules and experiments using model antigens with observations on immunity against infections or tumors to critically evaluate our perception and understanding of specificity, affinity maturation, antigen presentation, selection of the class of the immune response, immunological memory and protective immunity, positive selection of T cells and self/nonself discrimination.