The synthesis and localization of alternatively spliced fibronectin EIIIB in resting and thrombin-treated megakaryocytes

There are several species of alternatively spliced fibronectin (FN). One of these, FN EIIIB, is primarily present in embryonic and in proliferating and migrating cells and is believed to be important for cell maturation. We have studied the synthesis, localization, and secretion of this FN isoform in isolated guinea pig megakaryocytes, nonmegakaryocytic bone marrow cells, and platelets. There was 7.5 times more general FN in megakaryocytes than in nonmegakaryocytic cells based on the analysis of equivalent amounts of protein. FN EIIIB was detected by Western blotting in megakaryocytes but not in nonmegakaryocytic cells present in bone marrow. Neither megakaryocytes nor platelets secreted FN EIIIB, while megakaryocytes secreted 25.3% +/- 4.6% general FN and platelets secreted about 61% general FN in response to thrombin. Analysis of immunostained cells by confocal microscopy revealed that FN EIIIB had been redistributed to the surface of megakaryocytes in response to thrombin. Synthesis was studied by metabolic labeling, and megakaryocytes were shown to synthesize FN and FN EIIIB. Thus, megakaryocytes and platelets are among a small number of adult cells and tissues that synthesize and contain FN EIIIB. The expression of FN EIIIB on the megakaryocyte surface may influence migration and maturation.     

Detection of legionellas in clinical samples using FITC-marked antibodies

Using serogroup/species specific FITC-conjugates against Legionella (L.) pneumophila serogroups (SG) 1 to 6, L. micdadei, L. bozemanii and L. jordanis 186 sputum samples, 43 pleural fluids and bronchial washings and 39 lung tissue samples from 251 pneumonia patients were checked for Legionellae with the direct fluorescent antibody technique (DFAT). In samples from 201 patients which were negative if tested for antibodies and for urinary antigen and/or using culture methods, the DFAT was negative, too. One Pseudomonas strain isolated from a bronchial washing showed crossreactions. In 19 out of 49 patients with legionellosis L. pneumophila SG 1 (3x), SG 2 (1x), SG 3 (4x), SG 4 (1x), SG 5 (5x), L. micdadei (3x) and L. bozemanii (2x) were found. Positivity of the DFAT was significant higher in specimens, taken in early stages of illness (p less than 0.01). DFAT can be used for specific detection of Legionellae in clinical specimens, but the relative low sensitivity (39%) does not allow to exclude legionellosis. Further diagnostic tests like detection of antibodies and urinary antigen and culture are necessary to diagnose legionellosis.     

Effects of sex and estrous cycle on modulation of the acoustic startle response in mice

Potential sex differences in amplitude, habituation, prepulse inhibition (PPI) and prepulse facilitation (PPF) of the acoustic startle response (ASR) were investigated using male and female mice from the two different inbred mouse strains C57BL/6J (C57) and C3H. Furthermore, the effects of the estrous cycle were tested. The estrous cycle appeared to have no effect on ASR amplitude, habituation, PPF and PPI, the latter being in contrast to results in rats and humans. While sex had no effect on PPI or PPF, males exhibited higher startle amplitudes than females, irrespective of strain, which we discuss to be due to increased male anxiety. In addition, long-term habituation was stronger in C57 males and short-term habituation was weaker in C3H males with respect to females. These results provide evidence for influence of the reproductive hormones on startle reactivity and startle habituation; we therefore conclude that future studies involving genetic influences on behavior using inbred strains are only complete if both sexes are included.     

The Acoustic Startle Response in Inbred Roman High- and Low-Avoidance Rats

To investigate the emotional reactions of two rat strains selectively bred for good and poor two-way avoidance acquisition (RHA/Verh and RLA/Verh), male animals of both strains were tested in an acoustic startle response test. They received 40 acoustic stimuli followed by 10 electric foot shocks and another 30 acoustic stimuli. RLA/Verh rats showed a significantly higher startle response compared to RHA/Verh animals, indicating a stronger emotional reaction to acoustic stimuli. In addition, the former showed a stronger response to foot shocks. Combined with earlier findings, we conclude that selection for two-way avoidance learning does not result in cognitive defects in the RLA/Verh strain but, rather, in stronger emotional reactions to fearful stimuli.     

Untersuchungen über Fermente des menschlichen Blutes

Zusammenfassung Es wird eine schnell durchführbare photometrische Mikromethode zur Bestimmung der Acetylcholinesterase in Serum und Erythrocyten beschrieben, über deren chemische Grundlage bereits ausführlich berichtet wurde. Der Einfluß der Bebrütungszeit, der Fermentmenge, des Volumens, der Substratkonzentration, des p_H-Wertes und der Konzentration an physiologischer NaCl-Lösung wird untersucht, die Spezifität des Substrates Acetylcholin wird überprüft und diskutiert. Die Methode eignet sich gut zu laufenden Kontrollbestimmungen.