J. de Groot

Salivary protein/peptide profiling with SELDI-TOF-MS

Abstract:  In this study, large‐scale profiling of salivary proteins and peptides ranging from 2 to 100 kDa was demonstrated using surface‐enhanced laser desorption/ionization–time of flight–mass spectrometry (SELDI‐TOF‐MS). Results show that chip surface type and sample type critically affect the amount and composition of detected salivary proteins. Delayed processing time resulted in both increase and decrease of peak numbers consistent with proteolysis. SELDI‐TOF‐MS profiles also changed, depending on storage temperature, although sample processing by centrifugation and numbers of freeze–thaw cycles had a minimal impact. In conclusion, SELDI‐TOF‐MS offers a simple, rapid, high‐throughput technique for profiling low‐mass (<10 kDa) saliva proteins/peptides. We wish to use this technique to gain insight into the human saliva proteome composition and its changes over time in response to food consumption.

Repeated social defeat in female pigs does not induce neuroendocrine symptoms of depression, but behavioral adaptation

The aim of this study was to develop an animal model of major depression. Since two thirds of depressive patients are women, it is important to develop specific female animal models of depression. We therefore determined the consequences of chronic social defeat in individually housed prepubertal female pigs confronted with a dominant, older pig. Repeated defeat increased the salivary cortisol level, measured immediately after the confrontations, but this effect diminished after repeated confrontations. Neither organ weights nor the number of glucocorticoid (GR) and mineralocorticoid (MR) receptors in the ventral hippocampus were affected by repeated defeat. Serotonin turnover in the dorsal hippocampus was also unaffected. Behavioral analysis revealed that across confrontations, the pigs reduced the time spent actively attacking the dominant pigs, whereas the time increased in which the pigs passively underwent aggression and/or actively avoided aggression. Therefore, we conclude that the repeated social defeat paradigm does not induce long-lasting depression-like neuroendocrine effects as a consequence of behavioral adaptations (changes in the fighting strategy) in the young female pigs.

Radionuclides in detecting active granuloma formation. Gallium-67 scintigraphy and histopathology with autoradiographic findings.

Granuloma formation studies were performed on lungs of guinea pigs sensitized with FCA over 2 to 17 months. Prolonged time of sensitization revealed more granulomatous pulmonary tissue. An intravenous booster of FCA in the animals that had been sensitized for 3 months yielded enhanced granuloma formation within 5 days. The histopathology of these lungs was comparable with that seen in lungs of animals after 17 months of sensitization without booster. Enhanced local proliferation of macrophages, measured by [3H]thymidine incorporation and autoradiography, was seen in the lungs of the animals that had received boosters. Moreover, 67Ga scintigraphy was strongly positive in these animals. Scintigraphy of cell suspensions of pulmonary tissue from these animals showed that 67Ga was predominantly taken up (quantitatively as well as qualitatively) by the alveolar macrophages. Cell suspensions of sarcoidosis patients, prepared in the same way, showed only a low level of 67Ga uptake, one comparable to that of the pulmonary cell suspensions of the sensitized animals that had not received boosters. It is suggested that a negative scintigraphy in patients with chronic pulmonary granulomatous disorders could be (partly) explained by the absence of activated macrophages.