A. Savino

Urinary excretion of mutagens, thioethers and d-glucaric acid in workers exposed to bitumen fumes

SummaryThe authors carried out biological monitoring of the mutagenic/carcinogenic hazards associated with exposure to bitumen fumes during paving operations, analysing some biological parameters in the urine of a group of exposed workers. The urine samples were studied for mutagenicity by the Ames test and for thioethers concentration. d-Glucaric acid urine excretion was also determined to investigate the enzymatic induction potential of bitumens. Even though, in a previous environmental monitoring phase, a low content of mutagenic/carcinogenic compounds was found in bitumen and air samples, urinary mutagenicity data of exposed workers were statistically higher than those of a group of unexposed subjects. The urinary mutagenicity increased further if exposure to bitumens was associated with cigarette smoking. Thioethers were higher only in subjects exposed simultaneously to bitumens and cigarettes. d-Glucaric acid excretion did not increase significantly. The authors think that this type of coupled environmental and biological monitoring is a valid tool for a better evaluation of the mutagenic/carcinogenic exposure to bitumens or similar complex mixtures.

Mutagenicity studies and D-glucaric acid determination in urine of workers exposed to mineral oils

SummaryUrine from workers of a cold-rolling steel plant exposed to mineral oils were tested for the mutagenic activity by the Salmonella/microsome assay, and for D-glucaric acid content as a measure of hepatic mixed-function oxidase activity. An occupationally unexposed group served as control. The biological monitoring phase followed an environmental phase carried out in the working environment that showed a substantially low mutagenic/carcinogenic risk for the exposed workers. Urine samples were collected before, during and after work. From the results it was observed that the urinary mutagenicity was detectable only with TA98 strain in the presence of enzymatic activation (+ S9 mix). Further addition of beta-glucuronidase did not give any enhanced mutagenic effects. There was a significant difference in urinary mutagenicity between the exposed and control workers. However, in both groups the highest mutagenicity data was found in smokers: both exposed smoking workers and smoking controls had significantly higher urine mutagenicity than the non-smoking exposed and control workers. The results suggested a synergistic effect of smoking with exposure to mineral oils: the mutagenicity of urine from exposed smokers was significantly higher than that of control smokers. There was no difference in urinary D-glucaric acid results between exposed and unexposed groups, however, smokers of both groups had a significant increase in D-glucaric acid excretion. The authors suggest that even for this workplace with its low mutagenic/carcinogenic risk, smoking could interact with the complex mixtures present in the environment, and thus modify urinary mutagenicity data.

Mutagenic/carcinogenic hazards in a cold-rolling steel plant exposed to mineral oils: environmental monitoring phase

SummaryA survey was carried out in a cold-rolling steel plant exposed to mineral oils to study the mutagenic/carcinogenic hazards, following a coupled environmental/biological monitoring. The present paper deals only with the environmental phase by determining polycyclic aromatic hydrocarbons (PAH) and applying a mutagenicity test (Ames test), and includes the following steps: (a) work process and environment study; (b) sampling and analysing mineral oils before and after use (PAH determination and mutagenicity analysis); (c) sampling and analysing oil mist (TWA determination, PAH determination and mutagenicity analysis). The results showed that: (1) both unused and used (recycled) mineral oils contained only trace amounts of PAH and were not mutagenic; (2) the TWA concentrations of oil mists were lower than the TLV (< 5 mg/m3); (3) oil mists contained only trace amounts of PAH and were not mutagenic. The authors suggest that these results could be due to the moderate temperature of the oil during the work process and that there is a relationship between low PAH content and absence of mutagenicity in the oils and air samples.

Enzyme induction in rat lung and liver by condensates and fractions from main-stream and side-stream cigarette smoke

Aryl hydrocarbon hydroxylase (AHH) and dimethylnitrosamine demethylase (DMND) activities in pulmonary and hepatic tissues of male Sprague-Dawley rats were assayed following pretreatment with known inducers (benzo[a]pyrene, 3-methylcholanthrene, Aroclor 1254, phenobarbital) and with main-stream (MS) and side-stream (SS) cigarette smoke condensates and their related fractions. Biochemical assays by spectrophotofluorimetry (AHH activity) and spectrophotometry (DMND activity) and by a biological assay (Ames test) were performed to detect AHH and DMND induction. Ames test proved to be much less sensitive than the spectrophotofluorimetric analysis for AHH determination. Both main-stream and side-stream cigarette smoke condensates and some fractions, containing water-soluble bases, water-insoluble bases, and polycyclic aromatic hydrocarbons, were found to induce AHH activity in lung and liver, the lung being induced to the greatest extent. The highest levels of AHH inducibility were found for the SS-smoke condensate and related fractions. In particular, the insoluble bases fractions gave the highest induction. On the contrary, pulmonary DMND activity was not affected by pretreatment with the same materials, while hepatic DMND response was only minimally induced by Aroclor and phenobarbital treatment.

Dynamics of Enterococcus faecalis Colonization of Bone Marrow Transplant Patients

Enterococci have become increasingly important as a cause of hospital acquired infections. They are reported to be the third commonest cause of hospital acquired infections, responsible for approximately 10.7% of such infections6. Furthermore, enterococci have developed resistance to the antibiotics currently in use4. Up to now, few studies have investigated the dynamics of enterococcal colonization and this would appear to be a relevant step toward a better understanding of antibiotic-resistant enterococcal (ARE) colonization and infection. Many of the difficulties encountered in the study of enterococcal epidemiology have been due to the lack of a good typing method. But this has been aided in recent years by the introduction of DNA-based typing methods2, 7, 8, 9. In order to further our knowledge of enterococcal epidemiology we have studied the dynamics of E. faecalis colonization in bone marrow transplant patients using four typing methods.

Propuesta de valores de referencia ambientales microbiológicos en los servicios de restauración

INTRODUCTION To propose a new reference of microbiological environment monitoring in foodservice establishments. OBJECTIVE The present work shows the determination and evaluation of the microbiological contamination generated in a foodservice establishment Method: It is based on surface sampling (microbial build-up) using mixed cellulose ester membrane filters and on air sampling (hourly microbial adhesion) using Petri dishes. RESULTS Limits of contamination are established before and during the food elaboration, by means of the microbiological analysis of the environment, surfaces and equipment systems, until reliable limits and levels of acceptance are established of each selected point. Finally, a program of environmental microbiological monitoring was established including the evaluation of all parameters that compose and are implicit in the area, thus assuring and supporting its continuity with the documentation and registers developed for a safety area. Samples for microbiological examination were collected over a period of one moth on ten different days, at two different times. Twelve selected points having previously been identified as hazardous were monitored. Furthermore, foods though to be of high risk were periodically collected for microbiological analysis. CONCLUSIONS The possibility to use of an ample range of selective media, well over the limited number used in this study, allows the analysis of many single microbial species.

Enzymatic activities of human lung tissue: relationship with smoking habits

Twenty-two S12 preparations of surgical lung specimens obtained from smoker and non-smoker cancer patients were assayed to detect aryl hydrocarbon hydroxylase (AHH), dimethylnitrosamine demethylase (DMND), and glutathione-S-transferase (GST) activities, in both normal and neoplastic lung tissue from the same patients. Pulmonary fractions were also tested for their ability to activate some precarcinogens into mutagenic metabolites in the Ames test. Statistically significant differences were found for AHH and DMND activities between normal and neoplastic tissue of smoker patients. In addition, higher AHH activity in the neoplastic tissue of the smoker group was observed compared with that found in the non-smoker group. No differences were found for GST activity. All the lung S12 preparations were able to metabolize water-soluble bases and water-insoluble bases, derived from main-stream cigarette smoke condensate, into mutagenic agents in the Salmonella test system. However, S12 preparations from smoker group neoplastic tissues were more effective.