Effects of an ACTH/MSH(4-9) analog (HOE 427) on the sleep EEG and nocturnal hormonal secretion in humans.

The synthetic ACTH/MSH(4-9) analog HOE 427 ("ebiratide"), which is behaviorally the most potent ACTH-derived peptide but which is devoid of endocrine activity, was administered intravenously in a pulsatile mode 4 times (120 micrograms each) at 2200, 2300, 2400 and 0100 to study its effect on the sleep EEG and on concomitant hormonal secretion of cortisol and growth hormone. In comparison to placebo, the peptide produced signs of general activation associated with specific deteriorating effects on the quality of sleep. Sleep onset latency and intermittent wakefulness were increased, slow wave sleep was reduced, but only during the first 3 hours of the sleep period. The nocturnal secretory patterns of cortisol and growth hormone were unaffected by HOE 427. These effects are different from those reported in similar studies in which corticotropin-releasing hormone (CRH) was applied in humans, and they suggest that peripherally administered neuropeptides have specific nonendocrine behavioral effects.     

The site of action of the A-chain of mistletoe lectin I on eukaryotic ribosomes. The RNA N-glycosidase activity of the protein

The site of action of the A-chain of mistletoe lectin (ML-A) from Viscum album on eukaryotic ribosomes was studied. Treatment of rat liver ribosomes with ML-A, followed by treatment of the isolated rRNA with aniline, caused the release of a fragment with about 450 nucleotides from 28 S rRNA. Further analysis of nucleotide sequences of this fragment revealed that the aniline-sensitive site of phosphodiester bond was between positions A-4324 and G-4325 in 28 S rRNA. These results indicate that ML-A inactivates the ribosomes by cleaving a N-glycosidic bond at A-4324 of 28 S rRNA in the ribosomes as ricin A-chain does.     

Identification of a bone sialoprotein receptor in osteosarcoma cells

Bone sialoprotein (BSP) is an extracellular matrix glycoprotein associated with the mineral bone matrix. The amino acid sequence of BSP contains an Arg-Gly-Asp (RGD) sequence which confers to the protein cell binding properties (Oldberg, A., Franzén, A., and Heineg?rd, D. (1988) J. Biol. Chem. 263, 19430-19432). When BSP was used as an affinity matrix to isolate a cell surface receptor from rat osteosarcoma cells, a protein composed of polypeptides similar in size to those of a previously characterized vitronectin receptor was obtained. This putative BSP receptor, like the vitronectin receptor, bound also to an affinity matrix made of an RGD-containing heptapeptide. Moreover, similar patterns of inhibition of cell attachment to BSP and vitronectin was obtained with variant RGD-containing peptides, with BSP and with vitronectin. Finally, an anti-vitronectin receptor antiserum immunoprecipitated a receptor identical in size to the receptor bound to a BSP affinity matrix. These results show that BSP is recognized by an RGD-directed receptor and that both vitronectin and BSP can bind to this receptor.     

Nachweise von Zweitbruten beim Wei?sternigen Blaukehlchen (Luscinia svecica cyanecula)

Summary Close to the village Trieb in Upper Franconia (50° 09 N/11° 10 E) two cases of second breeding in the Bluethroat could be proved. The birds were colour-banded. Second broods are presumably rather common in the population along the upper River Main.     

Two novel matrix proteins isolated from articular cartilage show wide distributions among connective tissues

Two proteins of Mr = 58,000 and 59,000, respectively, were purified from 4 M guanidinium chloride extracts of articular cartilage by dissociative CsCl-density gradient centrifugation followed by gel chromatography on Sephadex G-200 and ion exchange chromatography on DEAE-cellulose. The two proteins differ in ionic properties and only the one with Mr = 59,000 bound to the ion exchanger. Although the two proteins showed dissimilar peptide patterns after proteolysis, their amino acid composition was similar, with very high contents of leucine and aspartic acid/asparagine. The two proteins showed no cross-reactivity in radioimmunoassays. By use of these assays, the proteins were demonstrated in extracts of most connective tissues, with high contents of about 0.1% of tissue wet weight determined in several types of cartilage. Among the non-cartilage connective tissues, tendon and sclera had the highest contents of the proteins, i.e. about 0.1% of the tissue wet weight. Bone extracts, on the other hand, contained insignificant amounts of the proteins. Only the Mr = 59,000 protein was detected in serum, its concentration being about 33 micrograms/l. Both proteins were shown to be localized in the extracellular matrix of cartilage, predominantly in the territorial matrix, by using indirect immunofluorescence.     

Respiratory-related cortical potentials evoked by inspiratory occlusion in humans

It has long been recognized that humans can perceive respiratory loads. There have been several studies on the detection and psychophysical quantification of mechanical load perception. This investigation was designed to record cortical sensory neurogenic activity related to inspiratory mechanical loading in humans. Inspiration was periodically occluded in human subjects while the electroencephalographic (EEG) activity in the somatosensory region of the cerebral cortex was recorded. The onset of inspiratory mouth pressure (Pm) was used to initiate signal averaging of the EEG signals. Cortical evoked potentials elicited by inspiratory occlusions were observed when C3 and C alpha were referenced to CZ. This evoked potential was not observed with the control (unoccluded) breaths. There was considerable subject variability in the peak latencies that was related to the differences in the inspiratory drive, as measured by occlusion pressure (P0.1). The results of this study demonstrate that neurogenic activity can be recorded in the somatosensory region of the cortex that is related to inspiratory occlusions. The peak latencies are longer than analogous somatosensory evoked potentials elicited by stimulation of the hand and foot. It is hypothesized that a portion of this latency difference is related to the time required for the subject to generate sufficient inspiratory force to activate the afferents mediating the cortical response.     

Stereoscopic back-scattered electron imaging of silver-stained proteins in nucleoli

By using simultaneously the AgNOR silver staining method, back-scattered electron imaging mode and stereo-tilt in scanning electron microscopy (SEM), it is possible to observe the nucleus through the cell surface, the nucleolus, and the tri-dimensional distribution of the AgNOR-associated acidic proteins. In C3H10T1:2 cells and their 7-12-dimethylbenz--anthracene-treated transformants, the staining demonstrates several intranucleolar silver-staining granules (SSG), surrounded by a weakly staining region. The SSG may represent the fibrillar center (FC) and the weakly staining region, the fibrillar dense component (FD). This component can link several SSG together to form a rope-like structure. In cells with no visible nucleolus and inactive nucleolar organizer regions (NORs) the silver-staining granules are less numerous, close together and the presumed fibrillar dense components are not visible. The SSG are located more peripheraly, and the weakly staining region and the rope-like structure are less prominent in control cell nucleoli than in transformed cells with a comparatively high rate of RNA synthesis.