Cat sympathetic ganglia in siru were quickly fixed bylocal perfusion fixation after different periods of stimulation, 1-30 min, at 10Hz, to study the membrane movements in the synapses of the preganglionic nerve fiber. Membranous structures, tubules and sacs in profiles and with resemblances to the axonal smooth endoplasmic reticulum (SER), were found to increase in number in the preterminal area, the unmyelinated part of the axon adjacent to the presynaptic bag, and also in the axon ending. The tubules, short and flattened in contour, appeared to compose a fine tubular network in the preterminal area as well as in the proximal part of the axon terminal. A composite tracing of the preterminal SER profiles with two serial sections displayed that the tubular network continuously stretched up to the axonal SER and at the same time extended down to the terminal interior spreading over the clusters of synaptic vesicles. Vesicles, similar in size and appearance to the synaptic vesicles, were often observed to bud off from the ends of the short tubules of the terminal SER. The SER tubules in the preterminal and terminal areas differed from the membranous structures of endocytotic origin which, distributed in the corresponding areas, were generally vacuolar in contour and liable to transform into C shaped structures or multivesicular bodies.
Co-localization of angiotensin II (A II) and renin in the growth hormone (GH)-containing cells of the bovine pituitary has been immunohistochemically demonstrated. A II has recently been shown to be present in the pituitary and involved in the regulation of secretion of pituitary hormones in addition to the classical physiological functions in the general circulation. To identify A II-producing cells, sections of the bovine pituitary were stained for the presence of A II and renin, an enzyme responsible for the formation of A II, using the avidin-biotin-peroxidase complex method. Anti-A II revealed a widespread distribution of moderately stained cells. Most of these A II-positive cells were also A II. Furthermore, co-localization studies indicated that the majority of A II- and reninstained cells were GH-immunoreactive. These results provide visual evidence for the intracellular formation of A II in the bovine pituitary where it helps to coordinate the secretion of other hormones.
Satellite cells of skeletal muscle from the adult hamster with hereditary myopathy were cultured and maintained for about one month. Electron microscopically, Z bands partially disappeared in some myopathic myotubes, as was previously reported. Furthermore, in other myopathic myotubes which contained relatively well-organized myofibrils, parts of Z bands were disorganized or streamed out. In such streamed out portions of the Z bands, periodic longitudinal filamentous densities running parallel to the axis of the myotube were distinct.
Fibroblast-like cells isolated from root pulps of bovine unerupted widsom teeth were shown to secrete both latent collagenase and collagenase inhibitor in culture. Molecular weights of the latent collagenase and the inhibitor were estimated to be 68,000 and 30,000, respectively, by gel filtration. Activated pulp cell collagenase cleaved type I collagen in solution into three-quarter (αA) and one-quarter (αB) length cleavage fragments and was inhibited by EDTA, o-phenanthroline, dithiothreitol, bovine serum, and pulp tissue collagenase inhibitor. The pulp cell inhibitor showed inhibitory activity against all the animal collagenases tested, except for bacterial collagenase. Double-immunodiffusion analysis using monospecific anti-pulp tissue inhibitor antiserum showed that the pulp cell inhibitor is immunologically identical to pulp tissue inhibitor.
With the use of anti-human G17 I serum (R-1301), antiserum R-1301 previously absorbed with pentagastrin (R-1301-G5), and anti-human G34[1-15] serum (R-2703), at least two subpopulations of gastrin-like immunoreactive cells were demonstrated in the pyloric mucosa of the adult rat. The majority of cells are reactive with all the antisera (typical gastrin-like immunoreactivity), but some cells react only with R-1301 (C-terminal immunoreactivity). A few cells of either subpopulation are present in the duodenum, but none in the pancreas of the adult rat. In the pyloric mucosa, typical gastrin-like as well as C-terminal immunoreactive cells first appear on day 20 of gestation, and gradually increase in number during postnatal development. In the duodenum and pancreas, C-terminal and typical gastrin-like immunoreactive cells first appear on day 18 and day 20 of gastation, respectively. In the duodenum, few remain during development. In the pancreas, typical gastrin-like and C-terminal immunoreactive cells disappear on postnatal day4 and day7, respectively. Extrapyloric gastrin cells in perinatal rats are mostly only C-terminal immunoreactive.
A renin-binding protein (RBP, Mr=20,000-40,000) was found in the mouse submandibular gland. The RBP, labile at low pH, was observed to bind renin to form a high molecular weight renin (Mr=75,000). The renin-RBP complex was dissociated by dilution. The RBP was partially purified by gel filtration and pepstatin-aminohexyl-Sepharose 4B column chromatography. The partially purified RBP contained renin inhibitory activity. The renin activity inactivated by the inhibitor was completely recovered by dilution. These results suggest that the RBP has renin-inhibitory activity.
Redox states of cytochromes were recorded simultaneously and continuously from the head, the intermediate, and the tail region of the isolated perfused rat pancreas. Selective occlusion of the coeliac artery induced parallel reduction of cytochromes α α3, b and c+c1, recorded with the probe of one scanning organ spectrophotometer placed on the surface of the tail region, in contrast to little, if any, change in the redox states of cytochromes recorded with the probe of another spectrophotometer placed on the surface of the head and the intermediate region of the isolated perfused rat pancreas. On the contrary, selective occlusion of the superior mesenteric artery induced little, if any, change in the redox states of cytochromes recorded from the tail region, in contrast to a distinct parallel reduction of cytochromes recorded from the head and the intermediate region. These results show that there is a functional discrimination between the region perfused with blood flow via the superior mesenteric artery and the region perfused with flow via the coeliac artery in the pancreas.
In the article ‘Tumor promoters may induce the appearance of extrachromosomal circular DNAs in rodent cell lines’ by H. Yamagishi, T. Kunisada, M. Toda, N. Ohnishi, H. Fujiki and T. Sekiguchi, which appeared in Biomedical Research 5 (5) 405-412 (1984), Fig. 2 and Fig. 4 were misplaced relative to each other, due to an error in the printing process. The figure on page 407 should have appeared on page 409 and vice versa.