Evaluating the Trend of VRE carriages in Health Facilities: A Retrospective Study from 2019-2022.

Background: Healthcare-associated infections (HAIs) and multidrug resistance (MDR) are a growing public health threat and pose a risk to patient safety in healthcare facilities. Vancomycin-resistant Enterococci (VRE) are responsible for nosocomial infections and have intrinsic and acquired resistance to many antibiotics, including glycopeptides. VRE carriage can remain undetected, increasing the risk of contact transmission. Identifying colonized patients is crucial for the implementation of preventive measures. Aims: The aims of this study were to evaluate the trend of VRE carriage based on rectal swab results between 2019 and February 2022 in a large Italian trust and the percentage of patients with VRE colonization at the time of hospitalization. Methods: This was a retrospective observational study based on results of rectal swabs performed for screening on admission between January 2019 and February 2022 in four hospitals part of a single trust in Turin, North-Western Italy. The study collected data on the date of specimen collection, type of specimen, isolated pathogen and the date of hospital admission. Descriptive analysis of data was performed, and duplicate samples were not considered. Results: From January 2019 to February 2022 we collected 5025 rectal swabs performed in hospitals of the trust, of which 3037 were performed in 2019 (60%), 741 in 2020 (15%), 611 in 2021 (12%) and 636 in the first two months of 2022 (13%). VRE positivity was found in 162 (3%) rectal swabs, of which 2 cases in both 2019 (0.1%) and 2020 (0.3%), 95 in 2021 (15.5%) and 63 in the first two months of 2022 (9.9%). Furthermore, 52% (84/162) of positive rectal swabs were performed at admission, whereas the remaining 48% (78/162) of positive rectal swabs were performed after 48h. Conclusions: This study found an increasing trend of VRE carriage in the study population during the SARS-CoV-2 pandemic, highlighting the importance of screening patients for VRE carriage to prevent worsening clinical conditions, environmental contamination, and prolonged hospitalization.

Enzyme-Linked Immunospot Assay as a Complementary Method to Assess and Monitor Cytomegalovirus Infection in Kidney Transplant Recipients on Pre-emptive Antiviral Therapy: A Single-Center Experience.

BACKGROUND: Cytomegalovirus (CMV) disease represents a major cause of post-transplantation morbidity and mortality. To estimate the risk of infection and monitor response to antiviral therapy, current guidelines suggest combination of viral load monitoring with direct assessment of CMV-specific immune response. We used enzyme-linked immunospot (ELISpot) for the evaluation of CMV-specific T-cell response in kidney transplant recipients with CMV viremia and investigated how information gained could help manage CMV infection. METHODS: Seventeen patients on pre-emptive antiviral therapy and CMV quantitative polymerase chain reaction (qPCR) ≥500 copies/mL (first episode after transplantation) were assessed using ELISpot and divided into Weak (9 patients with baseline ELISpot <25 spot-forming colonies [SFCs]/200,000 peripheral blood mononuclear cells [PBMCs]) and Strong Responders (8 patients with baseline ELISpot ≥25 SFCs/200,000 PBMCs). CMV-specific T-cell response, infection severity, viral load, and antiviral therapy were prospectively recorded and compared between groups at 1, 2, and 24 months of follow-up. RESULTS: Demographic and transplant characteristics of Weak and Strong Responders were similar. No episodes of CMV disease were observed. Weak Responders were more likely to experience CMV syndrome (56% vs 36.5%) and late virus reactivation (56% vs 25%) than Strong Responders. Weak Responders showed higher baseline median viral loads (19,700 vs 9265 copies/mL) and needed antiviral therapy for longer (179 vs 59.5 days). T-cell response showed 2 main patterns: early and delayed. CONCLUSIONS: ELISpot provides prognostic information about infection severity, risk of late reactivation, and response to therapy. Randomized trials, evaluating the need for antiviral therapy in kidney transplant recipients with asymptomatic infection and effective virus-specific T-cell immune response, are warranted.

Seroprevalence of five neglected parasitic diseases among immigrants accessing five infectious and tropical diseases units in Italy: a cross-sectional study.

OBJECTIVE: This multicentre cross-sectional study aims to estimate the prevalence of five neglected tropical diseases (Chagas disease, filariasis, schistosomiasis, strongyloidiasis and toxocariasis) among immigrants accessing health care facilities in five Italian cities (Bologna, Brescia, Florence, Rome, Verona). METHODS: Individuals underwent a different set of serological tests, according to country of origin and presence of eosinophilia. Seropositive patients were treated and further followed up. RESULTS: A total of 930 adult immigrants were enrolled: 477 men (51.3%), 445 women (47.9%), eight transgender (0.8%); median age was 37.81 years (range 18-80 years). Most of them had come from the African continent (405/930, 43.5%), the rest from East Europe, South America and Asia, and 9.6% (89/930) were diagnosed with at least one of the infections under study. Seroprevalence of each specific infection varied from 3.9% (7/180) for Chagas disease to 9.7% (11/113) for toxocariasis. Seropositive people were more likely to be 35-40 years old and male, and to come from South East Asia, sub-Saharan Africa or South America. CONCLUSIONS: The results of our study confirm that neglected tropical diseases represent a substantial health problem among immigrants and highlight the need to address this emerging public health issue.

Formaldehyde in residences: long-term indoor concentrations and influencing factors.

UNLABELLED: Chronic human exposure to formaldehyde is significantly increased by indoor sources. However, information is lacking on why these exposures appear to persist in older homes with aging sources. We use data from the Relationships of Indoor, Outdoor, and Personal Air study to evaluate 179 residences, most of which were older than 5 years. We assess the dependence of indoor formaldehyde concentrations (C(in)) on building type and age, whole-house air exchange rate, indoor temperature, and seasonal changes. Indoor formaldehyde had mean and median concentrations of 17 ppb, and primarily originated from indoor sources. The factors we analyzed did not explain much of the variance in C(in), probably because of their limited influence on mechanisms that control the long-term release of formaldehyde from aging pressed-wood products bound with urea-formaldehyde (UF) resins. We confirmed that the mitigating effects of ventilation on C(in) decrease with time through the analysis of data for new homes available in the literature, and through models. We also explored source control strategies and conclude that source removal is the most effective way to decrease chronic exposures to formaldehyde in existing homes. For new homes, reducing indoor sources and using pressed-wood with lower UF content are likely the best solutions. PRACTICAL IMPLICATIONS: Formaldehyde concentrations in homes due to indoor sources appear to persist throughout the lifetime of residences. Increases in ventilation rates are most effective in decreasing indoor concentrations in new homes where formaldehyde levels are high or when homes are tight. Consequently, other alternatives need to be promoted such as decreasing the amount of pressed-wood products with urea-formaldehyde (UF) resins in homes or reducing the UF content in these materials.

DNA damage in outdoor workers occupationally exposed to environmental air pollutants.

BACKGROUND: Health concerns about the exposure to genotoxic and carcinogenic agents in the air are particularly significant for outdoor workers in less developed countries. AIMS: To investigate the association between personal exposure to a group of air pollutants and severity of DNA damage in outdoor workers from two Mexican cities. METHODS: DNA damage (Comet assay) and personal exposure to volatile organic compounds, PM(2.5), and ozone were investigated in 55 outdoor and indoor workers from México City and Puebla. RESULTS: In México City, outdoor workers had greater DNA damage, reflected by a longer tail length, than indoor workers (median 46.8 v 30.1 mum), and a greater percentage of highly damaged cells (cells with tail length > or =41 microm); in Puebla, outdoor and indoor workers had similar DNA damage. There were more alkali labile sites in outdoor than indoor workers. The DNA damage magnitude was positively correlated with PM(2.5) and ozone exposure. Outdoor and indoor workers with > or =60% of highly damaged cells (highly damaged workers) had significantly higher exposures to PM(2.5), ozone, and some volatile organic compounds. The main factors associated with the highly damaged workers were ozone, PM(2.5), and 1-ethyl-2-methyl benzene exposure. CONCLUSIONS: With this approach, the effects of some air pollutants could be correlated with biological endpoints from the Comet assay. It is suggested that the use of personal exposure assessment and biological endpoints evaluation could be an important tool to generate a more precise assessment of the associated potential health risks.

Functional group characterization of indoor, outdoor, and personal PM: results from RIOPA.

UNLABELLED: Fourier transform infrared (FTIR) spectra of outdoor, indoor, and personal fine particulate matter (PM(2.5)) samples were collected during the Relationship of Indoor, Outdoor, and Personal Air (RIOPA) study. FTIR spectroscopy provides functional group information about the entire PM(2.5) sample without any chemical preparation. It is particularly important to characterizing the poorly understood organic fraction of PM(2.5). To our knowledge this is the first time that FTIR spectroscopy has been applied to a PM(2.5) exposure study. The results were used to chemically characterize indoor air and personal exposure. Sulfate was strongest in outdoor samples, which is consistent with the generally accepted understanding that sulfate is of outdoor origin. Absorbances attributed to soil dust were also seen in many outdoor and some indoor and personal samples. Inorganic nitrate absorbances were a common feature of many California and some New Jersey samples. Carbonyl absorbances showed substantial variation in strength, number of peaks, and wave number shift between samples, indicating variability in composition and sources. Absorbances attributed to aliphatic hydrocarbon and amide functional groups were enhanced in many personal and indoor samples, which suggested the influence of indoor sources in these homes. We speculate that meat cooking is one possible source of particulate amides. PRACTICAL IMPLICATIONS: To our knowledge this is the first time that FTIR spectroscopy has been used to characterize the composition of indoor and personal PM(2.5). The presence of sulfate, nitrate, ammonium, soil dust and a number of organic functional groups are all detected in one analysis on filter samples without extraction or other sample preparation. Differences between indoor and outdoor spectra are used to identify spectral features due to indoor-generated PM(2.5). Particularly interesting are the much larger aliphatic absorbances, shifts in carbonyl absorbances, and occasional small amide absorbances found in indoor and personal spectra but rarely in outdoor spectra. These observations are important because organics make up a large portion of PM(2.5) mass and their composition and properties are poorly characterized. The properties and behavior of organic compounds in airborne particles are often predicted based on their functional group composition. This analysis begins the development of a better understanding of the functional group composition of indoor and personal PM(2.5) and how it differs from that of outdoor PM(2.5). Eventually this will lead to an improved understanding of the properties, behavior and effects of PM(2.5) of indoor and outdoor origin.

Assessment of butadiene exposure in synthetic rubber manufacturing workers in Texas using frequencies of hprt mutant lymphocytes as a biomarker.

1,3-Butadiene (BD), which is used to manufacture synthetic rubber, is a mutagen and carcinogen. Because past occupational exposures have been associated with an increased risk of leukemia, there has been a dramatic reduction in workplace exposure standards. The health benefits of these reduced levels of occupational exposure to BD will be difficult to evaluate using relatively insensitive traditional epidemiological studies; however, biomarkers can be used to determine whether there are genotoxic effects associated with recent exposures to BD. In past studies of BD-exposed workers in Southeast Texas, we observed an increase in the frequency of lymphocytes with mutations in a reporter gene, hprt. Frequencies of hprt mutant cells correlated with air levels of BD and with the concentration of a BD metabolite in urine. Average exposures to 1-3 parts per million (p.p.m.) of BD were associated with a threefold increase in hprt variant (mutant) frequencies (Vfs). We now report results from a follow-up study of workers in a synthetic rubber plant in Southeast Texas. Thirty-seven workers were evaluated on three occasions over a 2-week period for exposure to BD by the use of personal organic vapor monitors and by determining the concentration of a BD metabolite in urine. The frequency of hprt mutants was determined, by autoradiography, with lymphocyte samples collected 2 weeks after the final exposure measurement. Based on their work locations, the study participants were assigned to high-exposure (N=22) or low-exposure (N=15) groups. The BD exposure, +/-standard error, of the workers in the high-exposure group (1.65+/-0.52 p.p.m.) was significantly greater than the low-exposure group (0.07+/-0.03 p.p.m.; P<0.01). The frequency of hprt mutant lymphocytes was also significantly different in the two groups (high, 10.67+/-1.5 x 10(-6); low, 3.54+/-0.6 x 10(-6); P<0.001). The concentration of the urine metabolite was greater in the high-exposure group, but the difference was not significant. The correlation coefficient between hprt Vf and BD exposure levels was r=0.44 (CI(95), 0.11-0.69; P=0.011). This study reproduced the findings from a previous study at this plant. Although studies of butadiene-exposed workers in other countries have not detected an effect of exposure on frequencies of hprt mutant lymphocytes, we have repeatedly observed this result in our studies in Texas.

Dietary vitamin E supplementation does not inhibit Candida albicans intestinal translocation in rats.

Candida albicans translocation was determined in rats receiving a normal or vitamin E-supplemented and deficient diet submitted to mesenteric ischemia and reperfusion (MIR). The antioxidant effect of vitamin E on lipid peroxidation was also assessed. The animals were divided into six groups submitted to different diets for 30 d. Groups N, NI, NC and NIC were submitted to a normal diet and used as controls, and groups VITE and DEFE received a vitamin E-supplemented and vitamin E-deficient diet, respectively. Groups NIC, VITE and DEFE were submitted to MIR, inoculated with Candida albicans and sacrificed 24 h after the surgical procedure. The antioxidant effect of vitamin E was determined in the liver and gut mucosa using the TBARS method. Candida albicans translocation was assessed in lymph node, liver and kidney specimens. The results showed that lipid peroxidation was lower (p < 0.05) in the vitamin E-supplemented group. However, vitamin E supplementation did not protect the rats against Candida albicans translocation (the translocation in the Group VITE was 100% for lymph nodes).

The role of information dissemination in sustainability of international partnerships.

The Fogarty-supported International Training Program of the Southwest Center for Occupational and Environmental Health (SWCOEH) at the University of Texas School of Public Health was initiated in 1995, with its activities focused primarily on Latin America. As this program has matured, its participants have been concerned about including elements that increase the likelihood that its trainees and projects will have a sustainable impact on occupational and environmental health in collaborating countries. The Center recently reviewed the experiences of various international organizations and national development agencies with established track records involving donor-supported projects. The authors summarize factors associated with project sustainability and describe how some of them are being incorporated into the SWCOEH program. Particular mention is made of the importance of supporting an infrastructure for broad information dissemination in the language of the intended audience. An example of a project to support a peer-reviewed Spanish-language journal devoted to occupational and environmental health, Salud de los Trabajadores, is presented.

Treatment of ipsilateral femoral neck and shaft fractures with the Russell-Taylor reconstructive nail.

Twenty-seven ipsilateral femoral neck and shaft fractures were treated with the Russell-Taylor reconstructive nail. Follow-up ranged from 6-48 months (average: 23.6 months). Femoral neck fractures healed within an average of 3.7 months and femoral shaft fractures healed within an average of 4.8 months. Complications included one case of avascular necrosis of the femoral head, a varus healing of one femoral neck fracture, and a rotational malalignment of the femoral shaft in another case. There were no cases of hardware failure. The Russell-Taylor reconstructive nail allows concomitant hip and shaft fractures to be fixed with a single implant.

Urban particle-induced apoptosis and phenotype shifts in human alveolar macrophages.

Epidemiological studies report a small but positive association between short-term increases in airborne particulate matter and small increases in morbidity and mortality from respiratory and cardiovascular disease in urban areas. However, the lack of a mechanistic explanation to link particle exposure and human health effects makes it difficult to validate the human health effects. The present study tested the hypothesis that urban particles could cause apoptosis of human alveolar macrophages(AM) and a shift of their phenotypes to a higher immune active state, which would provide a mechanism to explain an inflammatory response. Freshly isolated human AM were incubated for 24 hr with urban particles (#1648 and #1649), Mount Saint Helen's ash (MSH), and residual oil fly ash (ROFA). Cell viability was assessed by trypan blue exclusion and apoptosis was demonstrated by morphology, cell death ELISA, and DNA ladder formation. Additionally, AM were characterized according to RFD1(+) (immune stimulatory macrophages) and RFD1(+)7(+) (suppressor macrophages) phenotypes by flow cytometry. ROFA particles caused AM necrosis at concentrations as low as 10 microg/ml, urban particles had no effect except at 200 microg/ml, and MSH had no effect at 200 microg/ml. ROFA (25 microg/ml) and particles #1648 or #1649 (100 microg/ml) caused apoptosis of AM by all three criteria, but 200 microg/ml MSH had no effect. Finally, 25 microg/ml ROFA and 100 microg/ml particles #1648 or #1649 up regulated the expression of the RFD1(+) AM phenotype, while only ROFA decreased the RFD1(+)7(+) phenotype. Consequently, ROFA and urban particles can induce apoptosis of human AM and increase the ratio of AM phenotypes toward a higher immune active state (i.e., increased RFD1(+):RFD1(+)7(+) ratio). Ifurban particles cause similar changes in vivo, this could result in lung inflammation and possible increased pulmonary and cardiovascular disease.

Effect of different dietary levels of vitamin E on lipid peroxidation in rats.

The regulation of normal oxidative balance include the maintenance of adequate levels of dietary antioxidants such as vitamin E. The objective of this investigation was to study the effect of three different dietary levels of vitamin E (normal, supplemented 20 times higher and deficient) on plasma and liver lipid peroxidation, assayed by determination of thiobarbituric acid reactive substances (TBARS) and vitamin E in plasma and liver and hepatic reduced glutathione. Administration of dietary vitamin E caused a dose-dependent increase in liver and plasma concentration of this vitamin to 42.11 micrograms/g liver and 29.52 mumol/l respectively, in the supplemented group, and a low concentration of TBARS, 0.67 nmol/mg protein, in liver. The group receiving the diet without vitamin E showed high values of hepatic TBARS, 2.95 nmol/mg protein, and low values of reduced glutathione and reduced concentration of hepatic and plasma vitamin E (1.75 micrograms/g liver and 3.67 mumol/l, respectively). In conclusion, the vitamin E deficiency alone induces the liver lipid peroxidation in rats, and maintenance of adequate or higher vitamin E levels acts as a protective factor against free radical generation.

The immediate treatment of pelvic ring disruption with the pelvic stabilizer.

The management of the hemodynamically unstable patient with a severe pelvic ring disruption remains one of the most serious trauma emergencies. Standard resuscitation protocols may include attempted closure of the pelvic ring by the use of pneumatic anti-shock trousers, external fixation applied in the operating room, or a sheet wrapped around the patient in the emergency room. We report a case of pelvic ring disruption in which a successful clinical outcome was achieved with the emergent use of the Pelvic Stabilizer in the emergency room. The Pelvic Stabilizer is a device that can be effectively applied in the emergency room for the acute reduction and early stabilization of the displaced pelvis in a hemodynamically unstable patient. The use of a pelvic clamp can also be effective in the acute setting for a stable trauma patient with pelvic ring disruption. It rapidly reduces and stabilizes a potential cause for patient decompensation without obstructing access to further concomitant diagnostic or therapeutic interventions in the abdomen and perineum.

4-hydroxy-2-nonenal-protein adducts and apoptosis in murine lung cells after acute ozone exposure.

Ozone is a photochemically generated pollutant that can cause acute pulmonary inflammation and induce cellular injury and may contribute to the development or exacerbation of chronic lung diseases. Despite extensive investigation, the mechanisms of ozone and oxidant-induced cellular injury are still uncertain. Ozone has been reported to cause the formation of aldehydes in biological fluids that could explain many of the cellular effects caused by ozone. One of the most toxic aldehydes formed during oxidant-induced lipid peroxidation is 4-hydroxy-2-nonenal (HNE). HNE reacts primarily with Cys and secondarily with Lys and His amino acids, altering protein function and forming protein adducts that can be detected using specific adducts. In this study, we investigated whether ozone could cause the formation of HNE by assaying for HNE-protein adducts in cells isolated by lung lavage from C3H/HeJ mice exposed to 2.0 and 0.25 ppm ozone for 3 hr. Since oxidative stress and HNE have been shown to cause apoptosis we also examined the lung lavage cells for evidence of apoptosis following ozone exposure. Using a specific polyclonal antibody against HNE-amino acid adducts, two principle HNE-protein adducts were detected by Western analysis in cells obtained after ozone exposure at approximately 86-90 and 32 kDa. In addition to cell necrosis, apoptosis of lung cells was significant 3 hr after ozone exposure as detected using a Cell Death ELISA procedure and confirmed with DNA ladder and morphological analysis. The apoptotic cell injury peaked at 6 hr postexposure and decreased by 24 hr. Taken together, these results demonstrate that HNE is formed in vivo following ozone exposure and HNE appears to form specific protein adducts in lung cells. Furthermore, ozone can cause lung cell injury by an apoptotic mechanism in addition to a necrotic mechanism. Since HNE is toxic to cells and is formed as a result of ozone exposure, it may contribute to the lung cell injury following ozone exposure.

MF59 adjuvant enhances the antibody response to recombinant hepatitis B surface antigen vaccine in primates.

The effect of the proprietary adjuvant MF59 on the immunogenicity of a recombinant hepatitis B virus (HBV) vaccine, PreS2+SAg, was investigated in baboons. The magnitude and duration of the antibody response to hepatitis B surface antigen (anti-HBs) induced by the HBV/MF59 vaccine was compared with the same antigen combined with alum and with two licensed alum vaccines. After one immunization, the HBV/MF59 vaccine generated anti-HBs titers >10 mIU/mL in a greater proportion of animals, and mean titers were 26- to 84-fold higher than titers from alum vaccines. After a third immunization, the HBV/MF59 vaccine generated titers 38- to 127-fold higher than alum vaccines. Seven months after the third immunization, HBV/MF59 elicited titers 75- to 472-fold higher than alum vaccines. The dramatic immune response elicited by HBV/MF59 in baboons suggests that MF59 may be a desirable adjuvant for use in improved HBV vaccines for humans.

[Allergic rhinitis due to cockroach antigenic components. An emerging pathology?]. / La rinite allergica da componenti antigenici di blatta. Una patologia emergente?

The aim of our study was the evaluation of the role of these insects as causative agents of perennial rhinitis. We studied 317 subjects of both sexes (175 F and 142 M) living in Naples area and examined consecutively in our Centre for perennial nasal symptoms of suspected IgE mediated aetiology. All patients underwent the following diagnostic procedures: anamnestic procedures by using an internal questionnaire, clinical examination, skin prick test by using commercially available allergenic extracts and an allergenic extract containing the whole bodies of Blattella germanica and orientalis, Periplaneta americana. Blood samples for specific IgE determinations and a rhinologic visit were also carried out in patients with cockroach skin Prick test positivity. 14 of 317 subjects, prevalently young males, presented a skin positivity to cockroach allergens. All patients showed a moderate low degree of cutaneous and a low degree of serologic sensitization to allergens of these insects. Our preliminary data seem to demonstrate a mild role of cockroaches as causative agents of perennial rhinitis in Naples area. Further studies are necessary for a more appropriate knowledge of this allergy.

Phase II study of intensive chemotherapy with carboplatin, ifosfamide and etoposide plus recombinant human granulocyte colony-stimulating factor and sequential radiotherapy in locally advanced, unresectable non-small-cell lung cancer.

From June 1991 to August 1994, 61 patients with stage III unresectable non-small-cell lung cancer (NSCLC; 16 cases of stage IIIA with N2 bulky disease and 45 cases of stage IIIB) were treated with ifosfamide given i.v. at 3 g/m2 on day 1, carboplatin given i.v. at 200 mg/m2 on days 1 and 2, etoposide given i.v. at 120 mg/m2 on days 1-3 (ICE) and recombinant human granulocyte colony-stimulating factor (rhG-CSF) given s.c. at 5 micrograms/kg on days 4-13. Chemotherapy was given every 3 weeks for up to three cycles and, unless the disease progressed, was followed by thoracic radiotherapy on the tumor volume (total dose 60 Gy) and mediastinum (40 Gy). All patients had measurable or evaluable unresectable disease and a performance status (Eastern Cooperative Oncology Group) of 0-1. Only 61% of the enrolled patients received the full program of chemoradiotherapy according to the study design. At the end of sequential chemo-radiotherapeutic treatment, 41% of the patients had an objective response (24 partial responses and 1 complete response), 31% showed no change and 28% had progressive disease. The response rate noted for patients in stage IIIA with N2 bulky disease and that recorded for patients in stage IIIB did not differ significantly. The median time to progression was 5.4 months and the median survival was 8.2 months, with the 1-year survival rate being 31%. Sites of progression were mostly intrathoracic. Haematological toxicity was the main side effect, with grade III-IV thrombocytopenia being reported in 24% of the 165 courses of intensive ICE chemotherapy given. Febrile neutropenia was described in six courses (three patients). Non-haematological toxicities and radiotherapy-related side effects were generally mild and easily manageable. In conclusion, in unresectable stage III NSCLC a short program of moderately intensified ICE chemotherapy with rhG-CSF protection followed by sequential radiotherapy failed to increase the percentage of objective responses and reached a median survival comparable with that previously achieved with standard doses.

Lack of an EMF-induced genotoxic effect in the Ames assay.

A few epidemiological studies have linked exposure to electromagnetic fields (EMF) and the incidence of cancer. Since many carcinogens are mutagens in the Ames assay, the purpose of this study was to determine if exposure of four tester strains of Salmonella typhimurium (TA97a, TA98, TA100, and TA102) to EMF would increase their rate of mutation. Parallel plate electrodes and Helmholtz coils were used to create uniform field properties (300 V/in., 0.3 mT). Separate and combined alternating electric and magnetic fields effects were studied at a combined field frequency of 60, 600, and 6000 Hz at room temperature. These fields did not elevate the temperature of the culture plates above room temperature, Petri dishes containing each tester strain in top agar were exposed to an electric field (E), magnetic field (M), combined electric and magnetic field (EM), or no additional field above ambient conditions in the lab (control). Four plates containing each strain were exposed in each condition: two plates had the appropriate positive-control mutagen for each strain included in the top agar and two plates did not. Plates were exposed to either E, M, EM, or control conditions at room temperature for 48 hr. and then incubated an additional 24 hr. at 37 deg. C. The plates containing mutagen in the top agar showed an increased number of colonies consistent with mutagenesis. However, the rate of mutation in the S. typhimurium strains TA97a, TA98, TA100, and TA102 in either the presence or absence of mutagen was not affected by 48 hr. exposure at room temperature to E, M, or EM fields at 60, 600, or 6000 Hz.