Quantitation of autoradiographic grains in different zones of articular cartilage with image analyzer

Summary A novel method is introduced for the estimation of grain numbers in autoradiographic sections of articular cartilage with an image analyzer. It is based on separation of grains from the underlying structures by gray level thresholding and determination of the percentage of total area occupied by grains in a relatively large measuring field. The mean grain size is used as a reference to calculate grain numbers per cell profile and per unit area of tissue in various zones of bovine articular cartilage labelled with ³⁵S-sulphate in tissue culture. The results demonstrate considerable zonal differences as well as site related topographic variation in the rate of ³⁵S-sulphate incorporation. The largest site-related variation in the grain counts was observed in the superficial zone, suggesting a delicate control of proteoglycan synthesis in this zone.The IBAS program used in this work is available from Dr. J.J. Parkkinen or through Bitnet or EARN mail: MLAMMI at FINKUO     

Construction of linear GlcNAcβ1-6Galβ1-OR type oligosaccharides by partial cleavage of GlcNAcβ1-3(GlcNAcβ1-6)Galβ1-OR sequences with jack bean β-N-acetylhexosaminidase

Radiolabelled GlcNAc beta 1-3(GlcNAc beta 1-6)Gal (1), GlcNAc beta 1-3)GlcNAc beta 1-6)Gal beta 1-OCH3 (4), GlcNAc beta 1-3(GlcNAc beta 1-6)Gal beta 1-4Glc (7), and GlcNAc beta 1-3(GlcNAc beta 1-6)Gal beta 1-4GlcNAc (10) were cleaved partially with jack bean beta-N-acetylhexosaminidase (EC 3.2.1.30), and the digests were analysed chromatographically. All four oligosaccharides were hydrolysed faster at the (1-6) branch, than at the (1-3) branch, but a high branch specificity was observed only with the glycan 4. The saccharides 1 and 7 resembled each other in the kinetics of the enzyme-catalysed release of their two non-reducing N-acetylglucosamine units, but the glycan 10 was rather different. The partial digestions made it possible to obtain radiolabelled GlcNAc beta 1-6Gal, GlcNAc beta 1-6Gal beta 1-OCH3, GlcNAc beta 1-6Gal beta 1-4Glc, and, in particular, GlcNAc beta 1-6Gal beta 1-4GlcNAc.     

Production of xylonic acid byPseudomonas fragi

Summary Eleven microbial strains were tested for their ability to produce xylonic acid from xylose. The production of xylonic acid by one of the strains,Pseudomonas fragi ATCC 4973, was further studied in laboratory fermenter scale. The yield of xylonic acid was 92 % of original sugar. Xylonic acid production seemed to be growth associated and it was found to be very sensitive to the decrease of pH.     

Cation permeability induced by spermine and polybrene in rat liver mitochondria

The effect of the polybasic substances Polybrene and spermine on the passive and active transport of monovalent cations in mitochondria was studied. These agents were found to stimulate the low amplitude swelling of mitochondria. Volume oscillations were induced by addition of substrate in the presence of spermine. In conditions where weak oscillations were obtained without these substances, oscillations were stimulated and their frequencies increased in the presence of Polybrene and spermine. Their effects were maximal with 100–300 moles spermine per litre and 3–5 mg Polybrene per litre. These results are discussed in relation to an interaction of the agents studied with membrane negative charges which may be important regulators of ion transport.     

Ultrastructure of synaptosomes from one-day old and adult rat brain stem

Summary The ultrastructure and protein content of the five subfractions of the crude mitochondrial fraction from the brain stem of the 1-day old and adult rat was examined. The morphological composition of the subfractions after fixation in glutaraldehyde and osmiumtetroxide in the adult rat brain stem resembled that previously reported for the whole brain; synaptosomes sedimented in a sucrose gradient in subfractions C and D. In the 1-day old rat, mature synaptosomes were found in subfractions A, B, C and D; E contained mainly free mitochondria. 80–95% of the processes in the adult and 10–30% in the 1-day old rat contained synaptic vesicles which were of four types: (1) small agranular vesicles (2) large dense core vesicles (3) large agranular vesicles (4) coated vesicles. Pre- and postsynaptic membrane thickenings were demonstrated in many nerve-ending particles. In the subfractions of the 1-day old rat the protein content was one half and the distribution resembled that in the adult. Evidently nerve endings develop faster in the brain stem than in cortical areas; a serotoninor adrenergic origin of the early synaptosomes is suggested.This study was supported by a grant from the Paulo Foundation.     

Identification of enterochromaffin cells in adjacent Epon-embedded sections at light and electron microscopic levels

Summary Methods for light and electron microscopic comparison of individual argentaffin and argyrophil enterochromaffin cells (EC) in the sheep duodenal mucosa are described. These silver procedures were applied for light microscopy to Epon-embedded sections. The adjacent sections were examined with the electron microscope. The most specific characteristics of the argentaffin and argyrophil EC in electron microscopy are highly osmiophilic cytoplasmic granules. In one cell type these granules are smaller and more roundish than in the another type. These two cell types are stainable both by the argentaffin and argyrophil reactions. No essential difference can be observed in the localization of these elements. It is suggested that both cell types belong to the enterochromaffin system. Both silver methods are also suitable for the light microscopic identification of other intestinal structures in sections adjacent to that sectioned for electron microscopy.This work was supported by a grant from the Yrjö Jahnsson Foundation, Helsinki, Finland.The electron microscopic observations were carried out in the Electron Microscope Laboratory, University of Helsinki.     

Factors Influencing the Enhancement of the Infectivity of Poliovirus Ribonucleic Acid by Diethylaminoethyl-Dextran

The enhancement by diethylaminoethyl-dextran (DEAE-D) of the infectivity of poliovirus ribonucleic acid (RNA) for cell cultures was demonstrated by infective-center as well as by plaque assays, both in nonprimate (L) and primate cell systems (MK, HeLa, LLC-MK(2)). The sensitivity of plaque assays was greatly improved by using a tris (hydroxymethyl)aminomethane-buffered synthetic medium (basal medium Eagle) and freshly confluent cell monolayers. Enhancement of nucleic acid infectivity was directly dependent on the molecular weight of the DEAE-D. Two observations bearing on the action of DEAE-D appeared important: ribonuclease activity was reduced by DEAE-D, and cells pretreated with DEAE-D remained susceptible to infection with RNA in isotonic medium. Appreciable susceptibility of the treated cells persisted for at least 2 hr; the susceptible state could be reversed at will by an application of heparin. Enhancement of nucleic acid infectivity was independent of an effect of DEAE-D on intact virus and agar inhibitors.     

5-Hydroxytryptamine in the enterochromaffin cells of the guinea pig alimentary tract

Summary The histoohemical properties of the EC in the guinea pig alimentary canal were studied using the paraformaldehyde-induced fluorescence and five ordinary staining reactions. The fluorescence reaction was observed to be the most sensitive and specific one in the demonstration of the EC. Using the fluorescence and argyrophil techniques concomitantly, it was stated that all the fluorescent EC had also argyrophil properties. These observations lend further support to the author's earlier statement (Penttilä), 1966) that there is only one principal type of EC in the gastrointestinal tract. The argentaffin and other staining reactions were not able to colour all the EC, except in the duodenum.In the quantitative part of this study the EC number (No./mm) and the 5-HT (g/g) concentration were determined from the adjacent tissue pieces. Both quantities were absolutely at its highest in the duodenum and decreased in the caudal direction of the intestine. In the stomach the values were of the same magnitude as in the middle part of the intestinal tract. In the oesophagus there were no EC and the 5-HT content was negligible in comparison to the other gastrointestinal sites. The correlation between the EC number and the 5-HT content was highly significant from the stomach to the rectum. The 5-HT content per one EC was the largest in the duodenum. Comparing the histochemical and quantitative results the 5-HT location in the enterochromaffin system was discussed.