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1. The activities of choline acetyltransferase (CAT) and acetylcholinesterase (AChE) were assayed in adult pigeon ciliary ganglia, in the post-synaptic ciliary and choroid nerves, and in ciliary nerve iris terminals isolated from control birds and from animals from which the oculomotor nerve was previously transected. Enzyme activity levels were also measured in the iris terminals after surgical section of the ciliary nerves. From differences in enzyme activity between control and 3-day denervated tissues, the localization of CAT and AChE in pre- and post-synaptic elements of the ganglia and at the iris neuromuscular junctions was estimated. The fate of the preganglionic nerve terminals after denervation was investigated by electron microscopic examination of ganglia after surgical section of the oculomotor nerve.2. The CAT activity in the ganglion was distributed as follows: 60% in presynaptic elements, 31% in cell somas, and 9% in intraganglionic post-synaptic axons; in the iris junctions, 98% of the activity was present in the ciliary nerve terminals. For AChE: 20% was present in the preganglionic terminals, 69% in ganglion cell somas and the remaining 11% in post-ganglionic axons; at the neuromuscular iris junctions, 20% was found in the ciliary nerve terminals and 80% in the iris striated muscle.3. The first changes in the fine structure of the nerve terminals were observed 14 hr after surgery, and by 24 hr marked alteration of the synaptic structure were clearly recognized. No preganglionic endings were found in 3 day-old denervated ganglia.4. There was a positive correlation between CAT activity in the control iris nerve terminals and in ganglia. After denervation, when the activity of the enzyme decreased in ganglion cell somas, there was a corresponding decrease in the post-synaptic nerves. These two findings suggest that CAT slow axoplasmic transport is related to its perikarial concentration.5. There was a 60% reduction of CAT activity in the post-synaptic elements, assayed in the 10-day denervated ganglia, which was accompanied by a 30% decrease in activity in the iris nerve terminals. Similarly, post-synaptic AChE decreased approximately 30% in the ganglion and approximately 30% in the iris 10 days after section of the oculomotor nerve. At the same time, CAT activity also decreased in the nerve trunks, 70% at the ciliary nerve and 40% at the choroid; for AChE there were smaller changes.6. In contrast to CAT and AChE, there were no differences in ganglionic protein content, or lactate dehydrogenase (LDH), co-enzyme A (CoA) and monoamine oxidase (MAO) levels between short-term (3 days) and long-term (10 days) denervated ganglia.7. The later decrease of CAT and AChE activity in the cell somas, axons and nerve terminals after long-term preganglionic transection suggests that the activity of these enzymes is regulated across the synapses. It is postulated that the AChE regulation is part of a general ;trophic interaction' between neurones, but that the trans-synaptic modulation of CAT is specific for cholinergic cells.
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Although visualization of articular fluid on MR images of the knee is common, no specific MR criteria that enable assessment of the quantity of the effusion have been established. We performed MR of three cadaveric knee specimens after the instillation of increasingly large volumes of fluid and studied the distribution of the fluid. When 4 ml of fluid was injected, the anteroposterior diameter of the suprapatellar recess was 4 mm on midline sagittal MR images and 10.0-12.5 mm on lateral sagittal MR images, corresponding to the usual routine radiographic criteria for a knee effusion.
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The content of hyaluronan (HA), a common connective tissue component, was determined in well defined areas of the rat middle ear. The HA concentration in the pars flaccida of the tympanic membrane was considerably greater than in the pars tensa and areas on the medial wall of the middle ear cavity. The fate of exogenous HA introduced into the middle ear was also studied in rats. Tritium-labelled HA disappeared through the Eustachian tube (ET) and was followed by analysis of the nasopharyngeal secretion. The radioactivity in the secretion reached a peak at 3 h and decreased to almost zero within 12 h, indicating that most of the HA was removed. By autoradiography and direct analysis of the HA concentration and molecular weight distribution the fate of HA after obstruction of the ET was followed. Radioactive HA was confined to the middle ear and no uptake into surrounding tissues could be traced by autoradiography 4 days after application. The amount of HA that could be recovered from the middle ear was constant for up to 6 days. Analysis of the molecular weight distribution of the deposited HA indicated only slow degradation during these 6 days.
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Discelectrophoresis from 67 stimulated human parotid saliva samples was carried out in acidic and alkaline polyacrylamide gel-systems. Characteristical standard disc-electropherograms were obtained by means of quantitative densitometry and following statistical analysis. Application of standardized parotid discelectropherograms for diagnostics was discussed.
The pO2 on the arterioles' wall was shown to depend on the diameter of the vessels under study in rats. In normoxia, the pO2 tissue gradients are small and do not depend on the vessel diameter, whereas in hyperoxia a sharp drop of the tissue pO2 occurs at some distance from the vessel and the dependence of the pO2 on the arteriole diameter can be registered practically in all the sites of measuring. Radical arterioles and adjacent tissues of the brain cortex were shown to be most affected by a high arterial pO2 in hyperoxemia.
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