Biomedical subjects
Publications and source records attributed to J Schubert.
Histochemical studies of benign and malignant prostatic tumours for their differences in glucose-6-phosphatase activities are of interest by contributing to the accuracy of diagnosis of prostatic tumours. Studies by means of further histochemical methods are in progress.
Solutions of nucleic acid bases, nucleosides and a nucleotide, saturated with either N2, N2O or O2, were irradiated and tested for mutagenicity towards Salmonella typhimurium, with and without pre-incubation. Irradiated solutions of the nucleic acid bases were all non-mutagenic. Irradiated solutions of the nucleosides showed mutagenicity in S. typhimurium TA100 (pre-incubation assay). Generally, the mutagenicity followed the order: N2O greater than N2 greater than O2. The results show that the formation of mutagenic radiolytic products is initiated by attack of mainly OH radicals on the 2-deoxy-D-ribose moiety of the nucleosides. With irradiated solutions of the nucleotide, thymidine-5'-monophosphate, no mutagenicity could be detected.
Solutions of 2-deoxy-D-ribose and D-ribose were gamma-irradiated under different experimental conditions and tested for mutagenicity, with and without preincubation, in Salmonella typhimurium. The irradiated sugar solutions were mutagenic in the tester strains TA100 and TA98. Except for malonaldehyde (MDA), which is not mutagenic in the concentrations produced radiolytically, the relative mutagenicities of the individual radiolytic products are unknown. With irradiated solutions of 2-deoxy-D-ribose, a relationship was found between the level of non-MDA aldehydes and the mutagenicity in TA100. Heating the irradiated solutions of 2-deoxy-D-ribose resulted in a temperature-dependent reduction of the mutagenicity. Autoclaved, non-irradiated solutions of 2-deoxy-D-ribose were not mutagenic in the Salmonella test.
Conclusions as to the mutagenicity and carcinogenicity of metal salts can be ambiguous and misleading, especially for metal ions having a high charge/radius ratio, hence a strong tendency to hydrolyze. Using the rec-assay, we determined whether the mutagenicity of chromium salts was reduced by complexation, as in the case of Cr(VI), or induced in the case of Cr(III). We find that several chelants, in proportion to concentration, reduce or eliminate the mutagenicity of Cr2O32-. These include EDTA, salicylate (SA), and Tiron (disodium 1,2-dihydroxylbenzene-3,5-disulfonate). Cr(III) was rendered slightly mutagenic by salicylate and citrate. None of the chelating agents or their combinations were mutagenic.
Irradiation of Streptococcus faecalis in a neutral, N2O/Br- system leads to practically complete killing with extraordinarily low doses of irradiation, namely a D10 of 13 Gy compared to 470 Gy in N2, 250 Gy in N2O and 160 Gy in O2. However, irradiation and chemical investigations demonstrated that the apparent radiosensitization in neutral, N2O/Br- is due mainly to bromine, Br2 and HOBr rather than Br-3 or the radical anion, Br-2. For example, addition of unirradiated bacteria to a previously irradiated neutral solution of N2O/Br- reduces survival. The medium effects are eliminated by radiation chemical and/or chemical reactions which destroy bromine, such as occur in basic solutions, in N2/Br- or O2/Br- systems because of back reactions of Br2 with e-aq in the former and of Br2 with H2O2 and O-2 in the latter. Neither are medium effects produced in N2O/Br- systems at pH greater than 9. However, in N2/Br- the D10 = 82 Gy compared to 160 Gy in O2 which indicates that for S. faecalis Br-2 is intrinsically a more effective radiosensitizing agent than oxygen.
The inactivation of Streptococcus faecalis by radiolytically generated selective inorganic radical anions was investigated. The Br-2 radical, but not (CNS)-2, had a pronounced radiosensitizing action. In gamma-irradiated solutions at pH 7.0, the radiosensitization of a variety of scavenging systems was studied. Among these the D10 for N2/Br- was 0.082 kGy while N2O/CNS- = 0.35 kGy, N2O = 0.25 kGy, N2 = 0.47, and O2 = 0.16 kGy. As shown previously, inactivation in N2O/Br- systems is due mainly to Br2 and HOBr. From the variation of the inactivation with pH by Br-2 and (CNS)-2 it was deduced that tyrosine is crucial for the survival of S. faecalis via inactivation of enzymes with essential tyrosine residues such as aldolase and lipoyl dehydrogenase which are presumably needed to make energy available for DNA repair. Studies with a variety of scavengers also revealed that the t-butanol radical produced some radiosensitization of S. faecalis while the damaging effect of e-aq was much less than OH as shown by the D10 at pH 7.0; N2/t-butanol = 0.32 and N2/ethanol = 0.71. The radiosensitizing action of Br-2 in a natural environment containing sewage sludge was also determined, using the faecal streptococcal group as test organisms.
Chelation enables metals to be transported to or from vulnerable target sites, and to hinder or facilitate their carcinogenic potential. In the reverse sense, metals are capable of ligand scavenging via complexation or mixed complex formation--the latter being the result of interaction with binary complexes. Consequently, metal complexes can be utilized for the transport of selected organic chemotherapeutic drugs to target organs, or for the decorporation of those toxic organic compounds which are able, before or after metabolic activation, of reacting with metals or 1:1 metal complexes. It is emphasized that the degree to which metal ions interact in vivo should employ the conditional constants which take into account competition from other ions, especially Ca2+, H+, and OH-. The genotoxic consequences of the various chemical factors involved in chelation, along with examples: kinetics, stabilization of oxoidation states, lipophilicity, and mixed ligand formation, are discussed.
The individualisation of the diagnostics and the therapy of the carcinoma of the prostate renders necessary the coordination between medical check-up, statement and early forms of the carcinoma of the prostate, histological ascertainment, basis diagnostics and enlarged diagnostics as well as a highly specialised therapy. In the paper a model is demonstrated with the help of which it is possible to comprehend curable patients with carcinoma of the prostate and to use curative methods of treatment in a differentiated way. The author enters the possibilities of an exact TNM-determination. The continuation of curative methods of treatment, the intensifying of medical check-ups and the scientific optimization of palliative forms of treatment are decisive factors for the improvement of the survival rates in the carcinoma of the prostate.
Explore the source record for details and available documents.
On the basis of a complex roentgenologically diagnosed series of patients with carcinoma of the prostate a valuation of individual roentgenologic methods (excretion urogramme, urethrocystogramme, miction urogramme, vesiculogramme, cavernosogramme) for the T-determination are carried out. Here the standard programme of the UICC (1978) is confirmed, in which case the vesiculogramme additionally must be used in provided curative therapy. Additional roentgenologic methods are reserved to individual questionings. It is referred to a differentiated judgment of the category T3.
On the basis of 62 pelvic en bloc lymphadenectomies in the carcinoma of the prostate the lymphogenic formation of metastases is histologically determined. In 41 patients the comparison between lymphographic and histological N-determination is performed. The security of the lymphography in the carcinoma of the prostate in the lymphographically establishable pelvic region is recognized with 70%. By the pelvic en bloc lymphadenectomy in 50% of the cases a change of the preoperatively established N-determination takes place. The pedal lymphography is overestimated as method in the carcinoma of the prostate. As a secure technique in the determination of the lymphogenic formation of metastases at present the pelvic en bloc lymphadenomectomy with histological elaboration of the preparations is to be regarded. To this methods belongs a decisive diagnostic evidence in the determination of the formation of metastases of the carcinoma of the prostate by pelvic lymph nodes. The value of the lymphography consists in the simultaneous establishment of aortic metastases. Apart from this an intraoperative X-ray control may partly prove the radicality of the intervention.
It is referred to the importance of the pelvic lymphadenectomy for the estimation of the N-determination of the carcinoma of the prostate gland. The demonstration of intraoperative and immediately postoperative complication as well as the valuation of late complications and sequelae was for the first time performed on a larger series of patients. The avoidance of complication is shown and an outlook for further examinations is given.
Explore the source record for details and available documents.
Explore the source record for details and available documents.
Glucagon antibodies were produced in rabbits using three immunogenic glucagon conjugates. Glucagon was coupled to bovine serum albumin by difluorodinitrobenzene (DFDNB), carbodiimide (ECDI) or glutardialdehyde. Rabbits immunized with glucagon conjugated to albumin using DFDNB produced sensitive antisera for radioimmunoassay quite specific for pancreatic glucagon. The affinity constant of the best antiserum was approximately 10(11) l/mol. Antisera raised against the two other glucagon-conjugates were significantly less affine. All of these antisera showed inverse binding curves of 126J-glucagon caused by positive cooperatively in dependence upon the antigen/antibody ratio. The race of rabbits used for immunization was without influence on the immune response.
Transplantations of allogenic cialit conserved vessels were carried out in Alsatian dogs (German shepherd). The properties of the preservative stabiliser, the prservation methods, the technique of transplantation, the results and conclusions of the experiments were represented.
Explore the source record for details and available documents.
The reliability of roentgenological demonstration of the urethra in prostatic cancer has been examined and the advantages of double contrast retrograde urethrocystography and resistance miction-cystourethrography are accentuated. These investigations are indicated in preparation for radiotherapy, operative therapy, transurethral resection and after reduced uroflow.