Induktion von endogenem Pyrogen und Interferon durch Newcastle Disease-Virus in vivo

Zusammenfassung Die Ausbildung von endogenem Pyrogen und Interferon wurde nach der Injektion von NDV im Kaninchen untersucht. Das Auftreten und das Verschwinden beider Substanzen stimmte nicht nur zeitlich, sondern auch quantitativ überein. Zudem verliefen die Bildungskurven von endogenem Pyrogen und Interferon sowohl im Blut als auch in den Organen weitgehend gleichsinnig. Eine Abweichung von diesem Verhalten wurde lediglich in der Milz beobachtet, indem hier das endogene Pyrogen bereits nach 1 Stunde, das Interferon jedoch erst nach 3 Stunden den höchsten Gipfel erreichte. Dieser Befund deutet daraufhin, daß das endogene Pyrogen und das Interferon zwei verschiedene Substanzen sind.Die Exstirpation der Milz hatte ein gleichzeitiges Absinken des endogenen Pyrogens und des Interferons im Blut, jedoch nicht in der Leber, der Lunge und der Niere zur Folge. Hinsichtlich der Entstehung der partiellen bzw. kompletten Toleranz gegenüber dem NDV bzw. Influenza Virus A (PR8) dürften die beiden Substanzen demselben Mechanismus unterliegen.

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Induction of endogenous pyrogen and interferon by newcastle disease virus in vivo

Summary Endogenous pyrogen and interferon induced by injection of rabbits with NDV were investigated. The appearance and disappearance of both substances were in parallel in time as well as in quantity. The curves of endogenous pyrogen and interferon in the blood and in various organs tested usually were also parallel. Only in spleen highest titers of endogenous pyrogen were found already 1 hour after inoculation, whereas interferon activity reached its peak only after 3 hours. This finding indicated that endogenous pyrogen and interferon may be different substances.In splenectomized animals the blood levels of endogenous pyrogen and interferon were lower than those found in intact animals, while the titers in liver, lung and kidneys were identical. In respect to the formation of partial or complete tolerance to NDV and influenza virus A (PR8), respectively, both substances appear to be subjected to the same mechanism.

     

Correlation of preS antigens and clinical status during chronic hepatitis B virus infection

The serum kinetics of preS1 and preS2 antigens has been evaluated in 38 serial samples from eight patients with chronic active (CAH) or chronic persistent (CPH) hepatitis, followed for 2–7 years (mean 4.4 years) in whom liver biopsy was performed at intervals, and in 46 samples from ten asymptomatic HBsAg carriers followed for 4–5 years (mean 4.6 years). Four patterns of preS behaviour have been observed: (1) persistently positive preS1 and preS2; (2) disappearance of preS2; (3) disappearance of both preS1 and preS2; and (4) persistently negative preS1 and preS2. Pattern 4 has been observed exclusively among healthy carriers, while seven out of eight chronic patients exhibited either pattern 1 or 2. Among the chronic patients, preS2 disappearance was accompanied or followed by alanine aminotransferase (ALT) normalization. The correlation of preS antigens with conventional viral replication markers showed that 100% of hepatitis B virus (HBV)-DNA-positive and 86.6% of HBeAg-positive sera were preS1/preS2 positive, while 61% of HBV-DNA-negative and 64% of HBeAg-negative sera were preS1/preS2 negative. Our data suggest that continuous monitoring of preS antigens in follow-up sera will allow for an improved prognostic evaluation of chronic HBV infection.     

A Strain Device Imposing Dynamic and Uniform Equi-Biaxial Strain to Cultured Cells

The objective of this study is to design a new apparatus to allow the control of the magnitude and frequency of dynamic stretch applied uniformly to cells cultured on a silicon elastic membrane. The apparatus is designed to produce equi-biaxial dynamic stretches with area changes ranging from 0% to 55% and frequencies ranging from 0 to 2 Hz. Homogeneous finite strain analysis using triangles of markers was performed to compute the symmetric two-dimensional Lagrangian strain tensor on the membrane. Measurements of strain in both static and dynamic conditions showed that the shear component of the strain tensor (E_rc) was near zero, and that there was no significant difference between radial (E_rr) and circumferential (E_cc) components, indicating the attainment of equi-biaxial strain. Bovine aortic endothelial cells were transiently transfected with a chimeric construct in which the luciferase reporter is driven by TPA-responsive elements (TRE). The transfected cells cultured on the membrane were stretched. The luciferase activity increased significantly only when the cells were stretched by 15% or more in area. Cells in different locations of the membrane showed similar induction of luciferase activities, confirming that strain is uniform and equi-biaxial across the membrane. © 1998 Biomedical Engineering Society. PAC98: 8780+s, 8745-k, 8722-q     

A method that allows easy characterization of tumor-infiltrating lymphocytes

A method was developed to compare the lymphocytic infiltrates in regressing vs. progressing experimental mouse tumors using a model for human papillomavirus-16 (HPV-16) oncoprotein-linked cancer. Tumor cells mixed with matrigel, composed of natural matrix substances that provide a basement membrane structure for adherent cells, were inoculated into mice vaccinated with an efficacious vaccine to the E7 oncoprotein or a vaccine to a control antigen. The tumor cells remained within the solidified gel and recruited a cellular infiltrate that could readily be analyzed upon removal of the gelatinous mass containing progressing or regressing tumors. The results show that tumors recruit activated CD8(+) T cells regardless of their antigen specificity. In regressing tumors expressing an appropriate target antigen for the vaccine-induced CD8(+) T cells, a strong increase of the tumor antigen-specific T cell population was observed over time. Progressing tumors that lacked the target antigen for the activated CD8(+) T cell population did not show this selective enrichment.