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981.
Heparin, heparan sulphate, and various derivatives thereof have been oxidised with periodate at pH 3.0 and 4° and at pH 7.0 and 37°. Whereas oxidation under the latter conditions destroys all of the nonsulphated uronic acids, treatment with periodate at low pH and temperature causes selective oxidation of uronic acid residues. The reactivity of uronic acid residues depends on the nature of neighbouring 2-amino-2-deoxyglucose residues. d-Glucuronic acid residues are susceptible to oxidation when flanked by N-acetylated amino sugars, but resistant when adjacent residues are either unsubstituted or N-sulphated. L-Iduronic acid residues in their natural environment (2-deoxy-2-sulphoamino-d-glucose) are resistant to oxidation, whereas removal of N-sulphate groups renders a portion of these residues periodate-sensitive. Oxidised uronic acid residues in heparin-related glycans may be cleaved by alkali, producing a series of oligosaccharide fragments. Thus, periodate oxidation-alkaline elimination provides an additional method for the controlled degradation of heparin.  相似文献   
982.
Barbotin JN  Thomasset B 《Biochimie》1980,62(5-6):359-365
Protein foam structures bearing cells and organelles were produced by using a co-crosslinking method with serum albumin and glutaraldehyde at sub-zero temperature. Morphological observations obtained with scanning and transmission electron microscopy indicate macroporous and homogeneous structures. The glutaraldehyde concentration was varied to reveal its effect on immobilized red cells. It was observed that the structural appearance of preatreated cells or subcellular fractions (thylakoids from lettuce ; spheroplasts and chromatophores from R. capsulata) is preserved during the immobilization process. The morphological features of foam particles are always related to the observed kinetic activities of the specimens.  相似文献   
983.
Intracellular recordings were made from human oviduct smooth muscle maintained in cell culture. Solitary cells isolated from one another and cells in contact with one another retained electrical properties of smooth muscle in vivo. Membrane potential of solitary cells and connected cells was -35 mV. Connected cells formed electrotonic junctions which transmitted current from one cell to another. This current spread was responsible for differences in input resistance and time constant in solitary cells, 66 Momega and 96 msec, compared to connected cells, 26 Momega and 56 msec. All cells expressed delayed rectification to depolarizing current pulses. Some cells generated action potentials spontaneously or in response to intracellular current pulses. Action potentials were abolished by cobalt or by EGTA. Slow wave potentials, 5 . 20 mV in amplitude, occurred continuously once every 15 to 45 seconds in connected cells.  相似文献   
984.
Virological, serological and immunofluorescence studies revealed circulation of rhinoviruses of the strains 1A, 1B, 2, 3, 7, 9, 10, 12, 13, 14, 16-23, 27, 29-33, 42, 48, 53, 56, 60 and 69 on the territory of Czechoslovakia and the Soviet Union. According to virological results, type 48 predominated and was followed in frequency of occurrence by types 27, 14 and 16 in the USSR and 30, 1A and 31 in the CSSR. RV infection in adults with ARD diseases was the aetiology in 28.5% of cases. Among the causative agents of acute rhinitis, rhinosinusitis and otitis, rhinovirus infection makes up a large proportion. Interrelation has been found between rhinovirus infection and chronic inflammation of the mucosa of the nose, the accessory sinuses and the ears. Prolonged course of rhinovirus infection and isolation of the virus in the late stages of disease (1-4 months after its onset) support the presumption that rhinoviruses promote chronicity of inflammation. RV was isolated from patients with chronic pneumonia from the lower respiratory passages (bronchial secretion). Rhinoviraemia was found in a child who died of ARD.  相似文献   
985.
A calf thymocyte crude aqueous extract was tested for DNA synthesis inhibitory activity using phytohemagglutinin-stimulated human peripheral blood lymphocytes. Inhibition of DNA synthesis was assayed using tritiated thymidine and flow cytometry. Although the calf thymocyte crude extract inhibited tritiated thymidine incorporation by over 50%, only very slight changes in the flow cytometric analysis were observed. When dibutyryl-cyclic adenosine monophosphate was used as an inhibitor, a correlation in terms of the inhibition of tritiated thymidine to the inhibition by flow cytometry was observed.  相似文献   
986.
987.
The structure of the prosthetic group of citrate lyase (Klebsiella aerogenes) was studied by nuclear magnetic resonance and mass spectrometry. The spectra at 360 MHz of the nucleoside moiety (2'-ribosyladenosine) show the absence of 2'-hydroxyl proton, thus confirming the 2' position as the site of attachment of the second ribose moiety to the dephospho-CoA. This glycosidic linkage is found to be alpha(1" leads to 2') and is identical to that of poly(ADP-ribose). Studies of permethylation products by mass spectrometry support the above conclusion regarding the location of the ribosidic linkage.  相似文献   
988.
989.
This report concerns the isolation of bullous pemphigoid antigen from the nondialyzable urinary components of a patient with the disease. The isolation was accomplished by ion exchange chromatography and gel filtration. Pemphigoid antigen was found to be a basic glycoprotein that on SDS gel electrophoresis showed two major bands, one in the 18,000 m. w. region and the second with a m. w. of 74,000. Between these two bands, two additional bands appeared; one of 35,000 daltons and the other of 68,000 daltons. The 18,000 m. w. band was eluted from the gel and rerun on SDS gels. These gels showed the 18,000 m.w. band and also the appearance of the 35,000 and 74,000 m.w. bands. This finding indicates that urinary pemphigoid antigen may exist both as a single monomeric form and in polymeric aggregates.  相似文献   
990.
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