Possible relevance of pigeons as an indicator species for monitoring air pollution.

Wild city pigeons were caught at four different locations in the Netherlands to represent areas of high (Amsterdam-high), moderate (Amsterdam-medium), and low (Maastricht and Assen) traffic density. It is assumed that local ambient air pollution decreases as a function of traffic density. In these pigeons levels of polycyclic aromatic hydrocarbon (PAH)-DNA adducts, oxidative DNA damage, and heavy metal residues were determined in kidney, lung, liver, and blood (no adduct analysis in blood). The contribution of leaded gasoline to total body lead content was estimated by measuring concentrations of Pb and its isotopes in blood. We also analyzed samples of ambient air particulate matter for PAH and heavy metal concentrations at the four different locations. Interregional differences in heavy metals in ambient air particulate matter were reflected relatively well by pigeon body loads. The higher lead and cadmium concentrations in blood, kidney, liver, and lung were found in the Amsterdam high traffic density area, followed by Amsterdam medium, Assen, and Maastricht. A high Pb concentration in blood coincided with relatively low 206Pb/207Pb values, indicating a high contribution of leaded gasoline to total blood Pb concentrations in pigeons from the Amsterdam high traffic density area. Significantly enhanced blood zinc values were found in pigeons from both locations in Amsterdam compared to pigeons from the other two areas. However, no differences in Zn tissue levels between the four different groups were found. Oxidative DNA damage, determined as the ratio of 7-Hydro-8-oxo-2'-deoxyguanosine/ deoxyguanosine, in pigeon liver was highest in Amsterdam-high, followed by Assen (low traffic density). Pb content, but not the Cd content, was positively associated with oxidative DNA damage in liver tissue. In lung tissue, a negative correlation was found between oxidative DNA damage and Zn content. These results indicate that the carcinogenic potential of Pb might be ascribed to oxygen radical formation, whereas Zn plays a protective role against oxidative DNA damage. Places with high and medium traffic density could be clearly discriminated on the basis of PAH levels in the ambient air. The PAH content in particulate air samples was not, however, reflected in total PAH-related DNA adduct levels because no differences could be observed in tissue adduct levels in pigeons from the four different locations. Our results indicate that wild city pigeons can be used as biological indicators of exposure to heavy metal pollution in outdoor air.     

On the precision of diffusion/perfusion imaging by gradient sensitization.

Computer simulation is used to assess the precision and accuracy of diffusion and perfusion parameters derived from a set of gradient-sensitized images. Under ideal experimental conditions, a moderate signal-to-noise level (ca. 40) suffices to estimate diffusion coefficients to within 20% relative precision. However, estimation of a typical cerebral perfusion fraction of 5% to within 20% relative precision requires signal-to-noise levels of ca. 400. Simulations also show that systematic errors in perfusion fraction estimation, as well as underestimation of the uncertainties in perfusion parameters (by chi-squared analysis), will be found at moderate signal-to-noise levels.     

Pre-adaptation, adaptation and de-adaptation to high altitude in humans: hormonal and biochemical changes at sea level

High altitude residence is known to modify body biochemistry and hormone status. However, the effects of such a sojourn on these status observed at sea level both immediately and later after return are not as well established as are the effects of an intermittent acclimation. The aim of this study was therefore to investigate these changes. To achieve our objectives, nine subjects received intermittent acclimation at low pressure in a barometric chamber (8?h daily for 5 days, day 1 at 4500 m, day 5 at 8500 m) before an expedition to the Himalayas. Hormonal and biochemical changes were studied using samples of venous blood taken at sea level before and after acclimation, after return from the expedition and 1 and 2 months after descent. Concentrations of thyroid hormones, adrenaline, noradrenaline (NA), hormones of hydromineral metabolism (aldosterone, renin, arginine vasopressin, atrial natriuretic peptide) as well as prolactin, cortisol, insulin and endothelin 1 were measured. Biochemical measurements made were plasma osmolality, and concentrations of glucose, total cholesterol, total proteins, pre-albumin, transferrin, complement 3C, apolipoproteins A₁ and B and serum iron. Acclimation induced no alteration in hormone (except for NA with increases of about 1.5, fold P<0.05) and biochemistry data. After the expedition, hormone responses were characterized by a higher total triidothyronine concentration (+18%, P<0.05) while other hormones did not vary. A linear relationship was found between thyroid-stimulating-hormone and body mass changes after the expedition (r=0.67, P<0.05). The observed increased concentrations of plasma proteins and total cholesterol (P<0.05) could be related to the restoration of lean body mass. At 1 and 2 months after return, no changes in hormones were observed but a significant decrease in transferrin concentration was noticed. The higher serum iron concentration reported after 1 month (P<0.05) could have been the result of a physiological haemolysis. It was concluded that both acclimation and the expedition in the Himalayas affected hormone status and body biochemistry status even though the observed changes were slight and rapidly reversed.     

Early Response of Lung to Low Levels of Ozone

The epithelial response in the terminal bronchioles and alveoli was examined after exposure to approximately 0.5 and 0.9 ppm ozone (O₃). Loss of ciliated cells from the terminal bronchiole was pronounced after 6 to 10 hours of exposure; however, nonciliated cells were resistant to injury from O₃. In contrast, type 1 alveolar lining cells were very sensitive to O₂ and were severely damaged or removed from significant areas of the proximal alveoli after as little as 2 hours of exposure to 0.5 ppm. The basement lamina was left devoid of an epithelium with the exception of type 2 cells, which were very resistant and retained a relatively normal appearance. Under continuous exposure, repair of the lesion area was accomplished in approximately 48 hours through proliferation of the type 2 cells. The new cells were cuboidal at first but subsequently became more squamous in appearance. Exposure for 8 to 10 hours followed by residence in clean air resulted in a proliferative response at 48 hours, about equal to that observed after continuous exposure.     

Decreased human semen quality and organochlorine compounds in blood

BACKGROUND: Various studies have been performed in which potential effects of xenoestrogens on fertility or sperm parameters were investigated by comparing groups of subjects exposed to different levels of these chemicals. METHODS: In our study we used an alternative approach, as we selected one group of men with very poor semen quality and another group with normal semen quality and determined the blood organochlorine contents in order to determine whether a difference in these levels could be established. Organochlorine compounds, including polychlorinated biphenyls (PCB) and PCB metabolites, were detected using gas chromatography. The concentrations were compared between both groups, and related to semen parameters. RESULTS: A comparison of both groups did not reveal significant differences in organochlorine levels. Linear relationships were found when PCB and metabolite concentrations were related to the age of the volunteers. Focusing on the subgroup of men with normal semen quality showed that sperm count and sperm progressive motility were inversely related to the concentrations of PCB metabolites within this group. CONCLUSIONS: The finding of a significantly decreased sperm count in relation to an elevated PCB metabolite level within the subgroup of men with normal semen quality is important. This is the first time that a correlation between exposure to environmental pollutants with endocrine-disrupting capacity and human sperm quality has been observed.     

Comparison of single-shot localization methods (STEAM and PRESS) for in vivo proton NMR spectroscopy

Two single-shot localization techniques, STEAM and PRESS, are analyzed with regard to specifications for in vivo localized proton NMR. In particular, attention is paid to optimum signal intensity per unit volume, sensitivity to motion and diffusion, shortest attainable echo time, water suppression and editing possibilities. Experimental results are shown for cat brain at 4.7 T and human brain at 1.5 T. Both STEAM and PRESS are highly effective localization methods. For long echo times, PRESS is the method of choice, because it offers a factor of two gain in signal intensity. In addition, the method is less sensitive to motion and diffusion, and not susceptible to multiple-quantum effects. STEAM offers advantages for observation of (coupled) metabolites with short T2, because (a) shorter TEs can be attained and (b) effective water suppression sequences can be implemented without penalty in echo time. Differences relating to editing possibilities and B1 dependence, possibly important in choosing a method, are discussed.     

Genotoxicity and physicochemical characteristics of traffic-related ambient particulate matter

Exposure to ambient particulate matter (PM) has been linked to several adverse health effects. Since vehicular traffic is a PM source of growing importance, we sampled total suspended particulate (TSP), PM(10), and PM(2.5) at six urban locations with pronounced differences in traffic intensity. The mutagenicity, DNA-adduct formation, and induction of oxidative DNA damage by the samples were studied as genotoxicological parameters, in relation to polycyclic aromatic hydrocarbon (PAH) levels, elemental composition, and radical-generating capacity (RGC) as chemical characteristics. We found pronounced differences in the genotoxicity and chemical characteristics of PM from the various locations, although we could not establish a correlation between traffic intensity and any of these characteristics for any of the PM size fractions. Therefore, the differences between locations may be due to local sources of PM, other than traffic. The concentration of total (carcinogenic) PAHs correlated positively with RGC, direct and S9-mediated mutagenicity, as well as the induction of DNA adducts and oxidative DNA damage. The interaction between total PAHs and transition metals correlated positively with DNA-adduct formation, particularly from the PM(2.5) fraction. RGC was not associated with one specific PM size fraction, but mutagenicity and DNA reactivity after metabolic activation were relatively high in PM(10) and PM(2.5), when compared with TSP. We conclude that the toxicological characteristics of urban PM samples show pronounced differences, even when PM concentrations at the sample sites are comparable. This implies that emission reduction strategies that take chemical and toxicological characteristics of PM into account may be useful for reducing the health risks associated with PM exposure.     

Recurrent cardiac intimal sarcoma misdiagnosed as a myxoma or malignant transformation of a cardiac myxoma?

Cardiac intimal sarcoma is extremely rare and aggressive primary malignant cardiac tumors. Here, we reported the case of a young man initially operated for a tumor of the left atrium, causing a dynamic obstruction of the mitral valve and (mis‐)diagnosed as a myxoma at the histopathological analysis. Patient presented a local recurrence at 3 months and was reoperated. Pathology revealed this time the presence of an intimal sarcoma. Patient received adjuvant chemotherapy. Despite a good local control, the 1‐year follow‐up positron emission tomography scan revealed the presence of a metastasis in the left adrenal gland that was surgically resected. This article aims to highlight the risk of misdiagnosis in case of cardiac tumors, the hypothetical concept of malignant transformation of a cardiac myxoma, the aggressive course of the extremely rare cardiac intimal sarcoma, and the therapeutic modalities available to treat this pathology.