1,3-Propane sultone, an extremely potent experimental carcinogen: what should be expected in humans?

Kinetics of γH2AX and phospho-histone H3 following pulse treatment of TK6 cells provides insights into clastogenic activity

The desire for in vitro genotoxicity assays to provide higher information content, especially regarding chemicals' predominant genotoxic mode of action, has led to the development of a novel multiplexed assay available under the trade name MultiFlow®. We report here on an experimental design variation that provides further insight into clastogens' genotoxic activity. First, the standard MultiFlow DNA Damage Assay-p53, γ H2AX, phospho-histone H3 was used with human TK6 lymphoblastoid cells that were exposed for 24 continuous hours to each of 50 reference clastogens. This initial analysis correctly identified 48/50 compounds as clastogenic. These 48 compounds were then evaluated using a short-term, 'pulse' treatment protocol whereby cells were exposed to test chemical for 4 h, a centrifugation/washout step was performed, and cells were allowed to recover for 20 h. MultiFlow analyses were accomplished at 4 and 24 h. The γ H2AX and phospho-histone H3 biomarkers were found to exhibit distinct differences in terms of their persistence across chemical classes. Unsupervised hierarchical clustering analysis identified three groups. Examination of the compounds within these groups showed one cluster primarily consisting of alkylators that directly target DNA. The other two groups were dominated by non-DNA alkylators and included anti-metabolites, oxidative stress inducers and chemicals that inhibit DNA-processing enzymes. These results are encouraging, as they suggest that a simple follow-up test for in vitro clastogens provides mechanistic insights into their genotoxic activity. This type of information will contribute to improve decision-making and help guide further testing.

Determination of Propane-1,3-sultone in Workplace Air for Occupational Exposure Assessment

Propane-1,3-sultone (PS) is an alkylating substance used in the production of polymers, fungicides, insecticides, dyes, and detergents. It is absorbed into the human body by inhalation, digestion, and through the skin; it is also a possible carcinogen. Occupational exposure to this substance may occur on industrial or laboratory contact. In Poland, the maximum allowable concentration (MAC) for PS in workplace air is 7 µg/m3. The paper presents a method for determination of PS in workplace air using a gas chromatograph coupled with a mass spectrometer (GC-MS). Air containing PS is passed through a glass tube containing a glass fiber filter and two layers of silica gel. The substance is washed with acetonitrile and the solution obtained analysed using GC-MS. The measuring range for an air sample of 360 L is 0.7 ÷ 14 µg/m3. The limit of detection (LOD) is 13 ng/m3, limit of quantification (LOQ) is 40 ng/m3.

Synthesis and rheological characterization of water-soluble glycidyltrimethylammonium-chitosan

In this study, chitosan (CS) grafted by glycidyltrimethylammonium chloride (GTMAC) to form GTMAC-CS was synthesized, chemically identified, and rheologically characterized. The Maxwell Model can be applied to closely simulate the dynamic rheological performance of the chitosan and the GTMAC-CS solutions, revealing a single relaxation time pertains to both systems. The crossover point of G' and G" shifted toward lower frequencies as the CS concentration increased but remained almost constant frequencies as the GTMAC-CS concentration increased, indicating the solubility of GTMAC-CS in water is good enough to diminish influence from the interaction among polymer chains so as to ensure the relaxation time is independent of the concentration. A frequency-concentration superposition master curve of the CS and GTMAC-CS solutions was subsequently proposed and well fitted with the experimental results. Finally, the sol-gel transition of CS is 8.5 weight % (wt %), while that of GTMAC-CS is 20 wt %, reconfirming the excellent water solubility of the latter.

1,3-Propane sultone as an extremely potent human carcinogen: description of an exposed cohort in Germany

1,3-Propane sultone (1,3-PS) is a directly alkylating, genotoxic and carcinogenic substance. In rats, 1,3-PS induces local and systemic tumors at multiple sites, including the mammary gland, intestine, hematopoietic system, kidneys, and the central nervous system (CNS), especially in the form of gliomas. In one particular company, 1,3-PS had been manufactured in limited amounts in the 1950s and 1960s, and for a few purposes until the 1970s. The number of individuals having been in contact with the compound occupationally comprised 55 in total. Data were obtained from this group with an open question of legal compensation regarding an occupational disease. Particular emphasis was placed on malignancies occurring among the occupationally exposed persons. As cerebral gliomas are a major type of tumor induced by 1,3-PS experimentally, the occurrence of two glioblastomas among the previously exposed persons was significant. Three intestinal malignancies were recorded within the cases observed. It is also noteworthy that there was one case of a duodenal carcinoma, which is normally a rare human malignancy. Two hematopoietic/lymphatic malignancies were observed, and there was one case of a renal cell carcinoma. The types of malignancies within a group of only 55 exposed persons are surprisingly consistent with the results from rodent studies. Data clearly indicate that 1,3-PS is carcinogenic in humans. Evidence indicates that 12 cases with various neoplasms were legally compensated within the period of 1985-2010 as an occupational disease, based on the "opening clause" of § 9 (2) SGB VII of legislation in Germany.