Biomedical subjects
Publications and source records attributed to D Ionescu.
Nine analogues of methotrexate, in which the side chain is modified by replacement of the terminal glutamyl moiety with other amino acids, were synthesized from 2,4-diamino-6-(chloromethyl)pteridine. None of these compounds exhibited significant activity against L1210.
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The authors have performed 58435 microscopic examinations, of which 3813 were positive, and found 209 (5,48%) cases of non-cultivable Koch bacilli. The major bacteriological, clinico-evolutive and therapeutical aspects are examined. Most of the cases showing a syndrome of positive homogenate with a negative culture were rather recent ones (an evolution of less than 2 years in 73,68% of the total) and the highest frequency was found in those in which the treatment was in its first year. No direct relationship could be demonstrated between the number of germs (the Gaffky scale) and the frequency of the syndrome. The factors influencing the occurrence and the development of the syndrome are: the structure of the lesions, the method of bacteriologic examination, the therapy applied, and a certain immunologic reactivity. According to the authors the significance of this syndrome is positive in most of the cases, indicating a regression that has not been completed. The most reasonable attitude is a differentiated one, depending on each case, integrating the data obtained by the bacteriological examination in the therapeutic and evolutive clinico-radiologic context.
Data are presented on the separation and on some biochemical properties of an antigen to be used in the immunodiffusion (ID) test for detection of bovine leukemia virus. The antigen obtained proved to have the same efficiency in the ID test as a commercially available standard antigen. Experimental results suggest that the antigen is released into the culture fluid in the form of a glycoprotein molecule consisting of two subunits with a molecular weight of 60,000 linked by--SH bonds.
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The present paper reports on two methods for extraction of the protein antigen from Treponema Reiter and shows the chemical and immunochemical characteristics of the extracts. Serologic testing of 1810 sera from syphilitic patients in various stages of the disease, from healthy subjects and from subjects with a false positive reaction to lipoid antigens, showed the value of the Reiter antigen to be equal to the cardiolipin antigens and those prepared from pathogenic Treponema. It is recommended to associate this antigen, in view of its qualities, to the cardiolipin tests used in the serodiagnosis of syphilis, especially in the laboratories that do not currently apply other treponema tests.
Passive haemagglutination test with pathogenic Treponema pallidum antigen in the serodiagnosis of syphilis, carried out on 752 sera (518 syphilitic patients and 234 subjects without evidence of syphilis) showed a greater general sensitivity as compared the cardiolipin tests and complement fixation test with Reiter protein antigen, and lower, to immunofluorescence (FTA--ABS). Its specificity is relatively lower than that of the cardiolopin and treponemal tests. Associated with the cardiolipin test it may be preferably used for the detection of syphilis, and moreover, passive haemagglutination may confirm the diagnosis in case of weak positive results with the FTA--ABS test. The latter is, however, essential for problem cases.
Until lately, the host-parasite relationship in syphilis registered a certain latency because of the difficult approach to the problem and especially because of the enthusiasm caused by the possible eradication of the disease by penicillin. As these expectations were not confirmed, attention was again focussed on study by modern means of the biology of pathogenic treponema, its antigenic properties, possibility of in vitro cultivation and certain humoral and cellular immune aspects that govern the evolution of the disease and, probable, the acquiring of specific immunity. The attempts made for obtaining a live vaccine, attenuated by irradiation and experimented in animals, appear to foreshadow the possible use of this vaccine in the near future in man.
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