Acta biologica Academiae Scientiarum Hungaricae最新文献

The study of possible drainage pathways for the upper extremity after axillary lymphadenectomy by means of Indian ink injection shows: 1) that the single drainage is through the lateral upper arm bundle, but only if the latter joins the supraclavicular nodes or if its infraclavicular ending remains unremoved; 2) that the lateral bundle occur as either a long or a short type; 3) that with regard to the lymphatic drainage of the skin, areolae, zones and territories can be distinguished; 4) that a long bundle is the more suitable collateral way as collectors of the forearm territory join it; 5) that the most frequent cause of lymphedema is the fact that lymph of the forearm as well as of the dorsomedial upper arm territory can reach the lateral bundle only via the cutaneous plexus, over the lymphatic watersheds.

By means of electron cytochemical analysis of rat neuromuscular junctions subjected to perfusion with a calcium-containing (5 mM) aldehyde fixative, two kinds of presynaptic calcium binding sites were demonstrated. "A" sites are located above openings of junctional folds; these triangular elements are identical with presynaptic protrusions of the active zone and probably comprise calcium channels of the presynaptic membrane, "B" sites, located within the terminal axoplasm, are associated to multivesicular bodies probably accumulating surplus intracellular calcium. This fine structural arrangement enables a highly parsimonious usage of extracellular calcium in inducing release of acetylcholine from synaptic vesicles. Junctional folds of the postsynaptic membrane may funnel calcium ions exactly to spatially restricted calcium channels. Having entered the terminal through the channels opened by the arrival of nerve action potential, calcium ions may exert their action upon synaptic vesicles accumulated in the closest vicinity by means of stripping off hydration barriers and by inducing membrane fusions, that finally result in quantal release of acetylcholine from the terminal.

Submicroscopic alterations occurring in mouse spermatozoa during their sojourn into the female reproductive tract--as revealed by Scanning Electron Microscopy and Transmission Electron Microscopy using ruthenium red as marked for glycosaminoglycans--are described in the present investigation. The results show that the surface of the plasma membrane covering the acrosomal region of the spermatozoa found in the uterus--at different intervals of time after copulation (between 10 minutes up to 20 hrs)--are provided with an increasing number of granules and small vesicles. Some of the surface structures appear gradually leading to perforation of discrete areas of plasma membrane in regions corresponding to acrosomal areas covering the head of spermatozoa. Similarly ruthenium red preparations, show a significant decrease of glycosaminoglycans and their sialic acid moieties, which specifically precede further vesiculation and perforation of the sperm plasma membrane covering the same acrosomal regions.

The polycyclic aromatic hydrocarbon 3-methylcholanthrene (3-MC) is a well known inducer of the microsomal mixed function oxidase enzyme system in rat liver cells. It seems probable that the inductive action of 3-MC is realized, at least partly, at the transcriptional level of protein synthesis regulation. The present experiments indicated that in the liver of young rats there was a significant alteration in the activities of nucleolar as well as nucleoplasmic protein kinase and RNA polymerase enzymes during the first days of exposure to a single dose of 3-MC. The ultrastructural investigations showed that 3-MC treatment caused nucleolar hypertrophy and accumulation of lipid inclusions in the nucleoplasm.

Post mortem examination of a 60-year-old woman revealed that a new joint had developed at the border of the median and upper thirds of the ulna. The joint contained all the components of a complete articulation: articular cavity, capsule, articular surfaces, spongious bone, synovial tufts. The finding demonstrates that the human organism is able to form a new joint. The report is illustrated by photomicrographs taken from sections of the original material.

The ultrastructure of lip of Helix pomatia was investigated after application of distilled water, snail-ringer, sucrose and sodium chloride solutions. In the sensory dendrites, various types and degrees of morphological alterations were found, viz. changes in electron density of dendrites and mitochondria, occurrence of swollen cisternas, appearance of multilamellar and multivesicular bodies, development of electron-dense deposits in mitochondria and smooth-surfaced endoplasmic reticulum, fragmentation of cristae of swollen mitochondria and rearrangement of the smooth-surfaced endoplasmic reticulum. Occasionally, signs of degeneration and focal necrosis were also seen. Using different chemical stimulants, we failed to make morphological distinction between sensory dendrites although the differences in the chemo-specificity of receptors have been shown by electrophysiological investigations.

The effect of chlorpromazine (CPZ) treatment, the complete deafferentation of the medial basal hypothalamus (MBH) and their combination on 5-HT, DA and NE levels of the MBH, hypothalamic structures outside the MBH (RH), mesencephalon and amygdala were studied. Monoamines were determined by fluorimetry. CPZ reduced 5-HT in the hypothalamus (MBH, RH), DA in the amygdala and NE concentration in the RH. Complete deafferentation of the MBH decreased 5-HT in the MBH, DA in the amygdala and NE in the hypothalamus. CPZ + deafferentation of the MBH increased 5-HT concentrations in the hypothalamus (MBH and RH) and mesencephalon, and depressed DA levels in the amygdala and NE in the hypothalamus. The data suggest that the interruption of the neural connections of the MBH results in an inverse response of the hypothalamic serotoninergic elements to CPZ.

An inexpensive freeze-fracturing and etching equipment, based on the cold block principle, is described. The specimen is fractured inside the apparatus before replication with the aid of a simple fracturing device. The cleavage plane can be preselected and complementary fracture surfaces of tissue blocks are easily obtained. Since fracturing is carried out without the use of knife, large areas can be studied on the replica which is free of knife marks. Temperature measurement and heating of the lower block makes controlled etching possible. The apparatus can be constructed in a laboratory workshop at very reasonable expense; the results have been comparable to those obtained with most good quality or sophisticated freeze-etching equipments.

Changes in cell nuclei after infection of Lepidoptera cells, demonstrated by means of the fluorochrome "33 258H", permit the observation of virus DNA synthesis in a light microscope. Parallel occurring changes in cell surfaces, analysed in a scanning electron microscope, also permit an exact differentiation between infected and non-infected cells.