Chromosome analysis of lymphocytes from radiation workers in tritium-applying industry

Objectives : The frequency of chromosomal aberrations (CA) and micronuclei (MN) in peripheral blood lymphocytes was compared in two groups of persons occupationally exposed to tritium either through the use of luminous paints or in the weapons industry, with the aim of finding a correlation between the CA and MN assays, the extent of radiation hazard, and the duration of occupational exposure to chemical forms of tritium and the ability of the latter to induce hazards in human lymphocytes. Methods : CA analysis and the cytochalasin B micronucleus test were performed. Urinary tritium in both groups was measured using a liquid scintillation method. For purposes of comparison, 2 control groups (40 persons) were examined; 24 exposed individuals were matched to their controls according to age, sex, and smoking habits. Results: Values recorded for the frequency of CA in the group of workers handling tritium in luminous dial painting were 0.015 ± 0.014 dicentrics/cell, 0.023 ± 0.017 total unstable CA/cell, and 0.035 ± 0.019 MN/binucleated cell. Urinary levels of tritium in this group of employees ranged from 1.35 to 9.43 MBq/l. As compared with their matched controls, in these workers the differences in the yield of CA as well as in MN were statistically highly significant (P<0.005 and P<0.003, respectively). The same parameters analyzed in workers employed in the armament industry gave values of 0.001 ± 0.003 dicentrics/cell, 0.010 ± 0.008 total unstable CA/cell, and 0.021 ± 0.029 MN/binucleated cell. No detectable concentration of urinary tritium was found. As compared with their matched controls, in these workers the differences were also statistically significant (P<0.027 and P<0.012, respectively). The yield of CA, particularly the yield of dicentrics, was significantly higher (P<0.005) in the group of luminous dial painters as compared with the weapons industry workers. The difference found in the yield of MN between the two groups of workers was also statistically significant (P<0.084). Intercontrol differences in the yields of spontaneous CA as well as in MN were insignificant (P<0.683 and P<0.735, respectively). The results are discussed with respect to individual variations in the response to low doses of ionizing radiation, disorders in the handling of radionuclides, the duration of occupational exposure, and the chemical properties of the radionuclides used. Conclusion : Tritium in the chemical form of luminous paint is a more powerful clastogenic agent than tritium gas. Statistical analysis demonstrated that lymphocyte effects are due to the concentration of tritium in urine rather than to the duration of occupational exposure. Since the radiation hazard measured by the MN assay did not differ from that determined by the CA assay, the MN test can be recommended as a rapid assay for screening purposes in cases of occupational exposure to low radiation doses. Received: 20 November 1996 / Accepted: 1 August 1997     

Intramedullary spread of a cerebral oligodendroglioma

A case of intramedullary spinal metastasis of a cerebral oligodendroglioma is presented. This exceptional presentation, as well as the routes of dissemination, are discussed by review of the literature.     

Collaborative Evaluation of a Proposed Reference Dilution Method of Susceptibility Testing of Anaerobic Bacteria

An agar dilution method for susceptibility testing of anaerobic bacteria was evaluated to determine whether results obtained would be consistent enough to recommend it as a reference method. The study was conducted in 10 laboratories where the minimum inhibitory concentrations of six antibiotics (carbenicillin, cefoxitin, chloramphenicol, clindamycin, penicillin G, and tetracycline) were determined against 10 bacterial strains on Wilkins-Chalgren agar prepared by three manufacturers. Minimum inhibitory concentrations falling on the modes varied from 57 to 80% of all determinations and on the mode or within +/-1 log(2) dilution of the mode from 87 to 100% within each laboratory. When data from all laboratories were pooled, minimum inhibitory concentrations from each laboratory agreed with the overall mode 48 to 71% of the time, with an overall agreement at +/-1 log(2) dilution of 96%. This degree of reproducibility allows for recommendation of the procedure as a reference method. Results with three of the test strains were very consistent, and these strains are recommended as control strains: Clostridium perfringens ATCC 13124, Bacteroides fragilis ATCC 25285 and Bacteroides thetaiotaomicron ATCC 29741. The minimum inhibitory concentrations for these strains were on the mode or within +/-1 log(2) dilution of the mode 98, 99, and 99% of the time, respectively. The remaining anaerobic bacteria are recommended as reference strains.     

Über einen die Fettsäuresynthese steigernden Faktor der Leber

Ohne Zusammenfassung     

SYNTHESIS AND BIOLOGICAL ACTIVITY OF TUFTSIN AND OF [O=CTHR1]-TUFTSIN

The cyclization, under alkaline conditions, of N-benzyloxycarbonyl-L-threonine and of N-benzyloxycarbonyl-L-serine to produce 5-methyl-2-oxo-oxazolidine-4-carboxylic acid (O=CThr)and 2-oxo-oxazolidine-4-carboxylic acid (O=CSer), respectively, was investigated and found to be efficient and racemization-free. Similar was the cyclization which accompanied the basic hydrolysis of N-benzyl-oxycarbonyl-L-threonyl-L-phenylalanine methyl ester and of N-benzyloxy-carbonyl-L-seryl-DL-valine ethyl ester, and which resulted in the formation of L-O=CThr-L-Phe and L-O=CSer-DL-Val, respectively. The reaction was applied to the synthesis of [O=CThr¹] tuftsin, an active analog of the phagocytosis stimulating peptide tuftsin. A new synthetic route to tuftsin is also described.     

Autotransfusion in hepatic transplantation

Hepatic transplantation is often accompanied by a large volume of intraoperative blood loss which may place extraordinary transfusion demands on a community blood bank. In an effort to conserve blood bank resources, intraoperative autotransfusion has recently been used in our adult patients undergoing orthotopic hepatic transplantation. A group of seven patients receiving autotransfusion was studied and compared to another group of five patients who did not receive autotransfusion. In spite of receiving more blood during the transplant procedure, the autotransfusion group required a mean of 7.9 units less banked blood. Post-transplant transfusion requirements and bleeding complications were similar in both groups. Hematocrit and total bilirubin were not adversely affected, while transient elevation of BUN and serum creatinine appeared to be unrelated to the salvage process. This procedure was found to be safe and cost-effective, while conserving blood bank resources.     

Effect of fluoridated milk on caries: 3-year results

The effect of fluoridated milk consumption has been investigated in a follow-up study of 269 children aged 3-9 years. Children consumed 200 ml of milk daily, fluoridated in the groups 3-5 years with 0.4 mg F-, and in those aged 6-9 years with 0.75 mg F-, for 300 days yearly. The caries data were analyzed with special regard to changes in the DMF values of the permanent first molars, the yearly examination data of the corresponding age groups compared and correlated with the length of fluoridated milk consumption. Statistical analysis of the permanent first molar data showed significant negative correlation between DMF means and length of fluoridated milk consumption in children 5-6 years old at the time of evaluation. The caries reduction after 3 years was 74% and statistically significant (P less than 0.001). In children 7-9 years old the caries reduction of the permanent first molars was less, and statistically not significant. A slight reduction of DMFS mean values in the front teeth of this group could be observed.