Detection of Dirofilaria immitis in a brown bear (Ursus arctos) in Greece

Dirofilaria immitis (canine heartworm) is a filarial nematode found in the pulmonary circulation and the heart of susceptible hosts. It represents an important zoonotic vector-borne disease of domestic dogs and several wildlife species. Herein we report for the first time, the finding of Dirofilaria immitis worms in a brown bear killed in a vehicle collision in Northern Greece. The worms were morphologically identified; molecular examination, based on the analysis of the mitochondrial genes 12S (433 bp) and CO1 (610 bp), verified the identification by demonstrating 100% similarity to D. immitis specimens deposited in GenBank. Brown bears in Greece occupy habitats that are shared with the potential wild and domestic hosts and the vectors of D. immitis and thus may be particularly susceptible to this parasite. This report contributes to the knowledge of dirofilariosis spread in Europe and on the epidemiological threats that may affect the survival of the endangered brown bear in Greece.

Investigation of co-genotoxic effects of radiofrequency electromagnetic fields in vivo

We investigated the possible combined genotoxic effects of radiofrequency (RF) electromagnetic fields (900 MHz, amplitude modulated at 217 Hz, mobile phone signal) with the drinking water mutagen and carcinogen 3-chloro-4-(dichloromethyl)-5-hydroxy-2(5H)-furanone (MX). Female rats were exposed to RF fields for a period of 2 years for 2 h per day, 5 days per week at average whole-body specific absorption rates of 0.3 or 0.9 W/kg. MX was given in the drinking water at a concentration of 19 microg/ml. Blood samples were taken at 3, 6 and 24 months of exposure and brain and liver samples were taken at the end of the study (24 months). DNA damage was assessed in all samples using the alkaline comet assay, and micronuclei were determined in erythrocytes. We did not find significant genotoxic activity of MX in blood and liver cells. However, MX induced DNA damage in rat brain. Co-exposures to MX and RF radiation did not significantly increase the response of blood, liver and brain cells compared to MX exposure only. In conclusion, this 2-year animal study involving long-term exposures to RF radiation and MX did not provide any evidence for enhanced genotoxicity in rats exposed to RF radiation.

Effects of mobile phone radiation on UV-induced skin tumourigenesis in ornithine decarboxylase transgenic and non-transgenic mice

PURPOSE

The effects of low-level radiofrequency radiation (RFR) on ultraviolet (UV)-induced skin tumorigenesis were evaluated in ornithine decarboxylase (ODC) and non-transgenic mice.

MATERIALS AND METHODS

Transgenic female mice over-expressing the human ODC gene and their non-transgenic littermates (20 animals in the cage control group, and 45-49 animals in the other groups) were exposed for 52 weeks to UV radiation or a combination of UV radiation and pulsed RFR. The UV dose was 240 Jm(-2) (1.2 x human minimum erythemal dose) delivered three times a week. One group of animals was exposed to Digital Advanced Mobile Phone System (DAMPS)-type RFR, the other group to Global System for Mobile (GSM)-type RFR at a nominal average specific absorption rate of 0.5 W kg(-1), 1.5 h day(-1), for 5 days a week. The skin was carefully palpated weekly for macroscopic tumours. Histopathological analyses of all skin lesions and of a specified dorsal skin area were performed on all animals.

RESULTS

UV exposure resulted in development of macroscopic skin tumours in 11.5 and 36.8% of non-transgenic and transgenic animals, respectively. The RFR exposures did not give a statistically significant effect on the development of skin tumours in either transgenic or non-transgenic animals, or in combined analysis, but tumour development appeared slightly accelerated especially in non-transgenic animals. No effects of RFR exposures were found on excretion of 6-hydroxymelatonin sulphate into urine or on polyamine levels in dorsal skin.

CONCLUSION

RFR exposures did not significantly enhance skin tumourigenesis. However, the slightly accelerated tumour development may warrant further evaluation.

Effects of mobile phone radiation on X-ray-induced tumorigenesis in mice

The increased use of mobile phones has raised the question of possible health effects of such devices, particularly the risk of cancer. It seems unlikely that the low-level radiofrequency (RF) radiation emitted by them would damage DNA directly, but its ability to act as a tumor promoter is less well characterized. In the current study, we evaluated the effect of low-level RF radiation on the development of cancer initiated in mice by ionizing radiation. Two hundred female CBA/S mice were randomized into four equal groups at the age of 3 to 5 weeks. The mice in all groups except the cage-control group were exposed to ionizing radiation at the beginning of the study and then to RF radiation for 1.5 h per day, 5 days a week for 78 weeks. One group was exposed to continuous NMT (Nordic Mobile Telephones)-type frequency-modulated RF radiation at a frequency of 902.5 MHz and a nominal average specific absorption rate (SAR) of 1.5 W/kg. Another group was exposed to pulsed GSM (Global System for Mobile)-type RF radiation (carrier-wave frequency 902.4 MHz, pulse frequency 217 Hz) at a nominal average SAR of 0.35 W/kg. The control animals were sham-exposed. Body weight, clinical signs, and food and water consumption were recorded regularly. Hematological examinations and histopathological analyses of all lesions and major tissues were performed on all animals. The RF-radiation exposures did not increase the incidence of any neoplastic lesion significantly. We conclude that the results do not provide evidence for cancer promotion by RF radiation emitted by mobile phones.

The effect of age and density of the breast on the sensitivity of breast cancer diagnostic by mammography and ultasonography

PURPOSE

We studied which, age of the patient or density of the breast accounts for the sensitivity of mammography and ultrasonography (US). Furthermore we studied whether the overall impression on the density of the breast or the density in tumour area accounts for the sensitivity of mammography and ultrasonography.

MATERIALS AND METHODS

The material consisted of 572 consecutive histologically and 5 cytologically verified breast cancer cases. Mammography and US examinations were performed immediately before breast cancer operations and information on the findings were received from the original patient files and classified as malignant or benign. The density of breast parenchyma to fatty, mixed or dense in total breast and separately in tumour area was defined by a radiologist group from the original mammograms by comparing to model mammograms. The sensitivity (Se) of mammography and US was compared in 3 age groups (26-49, 50-59 and 60-92) and in the different density classes.

RESULTS

Sensitivity of mammography increased by age (density-adjusted OR = 0.2, 95%, CI 0.1-0.5) in age group 26-49 compared to age group 60-92) and with fattiness of the breast (age-adjusted OR= 0.4, 95%, CI 0.1-1.0 for dense breast parenchyma in tumour area compared to fatty breast). Sensitivity of US was inversely related to age (density-adjusted OR = 2.3, 95%, CI 1.0-5.2 in age group 26-49 compared to age group 60-92) and directly related with fattiness of breast (age-adjusted OR = 0.5, 95%, CI 0.2-0.9 by dense breast parenchyma in tumour area compared to fatty breast). Density in the tumour area compared to total breast density was related only mariginally better sensitivity both of mammography (0.4 vs. 0.6) and of US (0.5 vs. 0.6).

CONCLUSION

Sensitivity of both mammography and sensitivity of US are independently related both to the age of the patient and to the density of the breast. The effect of age is inverse and that of density parallel between mammography and US on sensitivity. The effect of overall breast density was close to the effect of density at the site of the tumour on the sensitivity of both mammography and US.

Effects of 50 Hz magnetic fields on cancer induced by ionizing radiation in mice

PURPOSE

To evaluate the effects of 50 Hz magnetic fields (MF) on the development of cancer induced by ionizing radiation.

MATERIALS AND METHODS

A total of 150 female CBA/S mice were randomized into three equal groups at the age of 3-5 weeks. One of the groups served as a 'cage-control group'. The two other groups were exposed to ionizing radiation in the beginning of the study. One of these two groups was exposed 24 h per day, for 1.5 years, to a 50Hz vertical MF, the intensity of which varied regularly between 1.3, 13 and 130 muT. The other served as a control group and was sham-exposed to MF in similar, but unenergized, exposure racks. Body weights, clinical signs, and food and water consumption were recorded regularly. Haematological examination, and the histopathological analysis of all lesions and major tissues were performed on all animals.

RESULTS

MF exposure did not increase the incidence of any primary neoplasms. However, the incidence of basophilic liver foci, a probable pre-neoplastic change in liver, was increased. The incidence of hepatocellular adenomas was unchanged, whereas the incidence of hepatocellular carcinomas was slightly, but not statistically significantly, elevated.

CONCLUSIONS

It is concluded that overall the results of this study do not support a role for MF as a tumour promoter.

Validity of radiological examinations of patients with breast cancer in different age groups in a population based study

By studying which radiological examinations had been performed before breast cancer operations the aim was to assess, how much benefit ultrasonography (US) and fine or core needle biopsy (FNAB, CNB) gave in addition to mammography, and whether the sensitivity of these examinations varied with the age of the patient. There were 659 consecutive histologically and six cytologically verified breast cancer cases included in the study. Information on mammography, US and FNAB findings were retrieved from the original patient files and classified as malignant or benign. The sensitivity (Se) of these was compared in three age groups (26-49, 50-59 and 60-92). Seventeen (3%) tumours had operations without any radiological examination and 73 (11%) without cytological or histological verification. The sensitivity of mammography (Se=0.92) was statistically significantly higher than the sensitivity of FNAB (Se=0.85, P=0.002) or US (Se=0.86, P=0.003). The sensitivity of mammography increased with age; US sensitivity was slightly higher amongst younger than older patients; the sensitivity of FNAB did not depend on the age of the patient. The sensitivity using a cutoff level of class 5 for mammography was higher (50% typical malignant findings) than for US (45%) or FNAB (30%). Among cases with benign mammographic finding (classes 1-2), the US finding was malignant (classes 3-5) in 4% and FNAB was malignant in 7%. Mammography is a reliable method of breast examination especially for women over 50 years of age. Ultrasonography is beneficial, particularly in younger women, but it is mainly performed as a complementary examination to a mammography and therefore could not be evaluated as an independent examination. FNAB and CNB results were not related to the age of the patient.

The visibility of cancer on previous mammograms in retrospective review

AIM

To study how many tumours were visible in restrospect on mammograms originally reported as normal or benign in patients coming to surgery with proven breast cancer. The effect of making the pre--operative mammogram available was also assessed.

MATERIALS AND METHODS

Three hundred and twenty initial mammograms of consecutive new breast cancer cases were analysed by a group of radiologists in the knowledge that all patients were later diagnosed with breast cancer. The films were read twice, first without and then with the later (pre-operative) mammograms available. The parenchymal density in the location of the tumour was classified as fatty, mixed or dense, and the tumours were classified as visible or not visible. The reasons for the invisibility of the tumour in the earlier examination were analysed.

RESULTS

Fourteen per cent (45) of cancers were retrospectively visible in earlier mammograms without the pre-operative mammograms having been shown, and 29% (95) when pre-operative mammograms were shown. Breast parenchymal density decreased with age and the visibility of tumours increased with age. When considered simultaneously, the effect of age (over 55 vs under 55) was greater (OR = 2.9) than the effect of density (fatty vs others) (OR = 1.5). The most common reasons for non-detection were that the lesion was overlooked (55%), diagnosed as benign (33%) or was visible only in one projection (26%). Growing density was the most common (37%) feature of those lesions originally overlooked or regarded as benign.

CONCLUSIONS

Tumours are commonly visible in retrospect, but few of them exhibit specific signs of cancer, and are recognized only if they grow or otherwise change. It is not possible to differentiate most of them from normal parenchymal densities. Saarenmaa, I. (2001). Clinical Radiology56, 40-43.