Annual variation of (7)Be soil inventory in a semiarid region of central Argentina.

Reliable information on environmental radionuclides atmospheric entrance, and their distribution along the soil profile, is a necessary condition for using these soil and sediment tracers to investigate key environmental processes. To address this need, (7)Be content in rainwater and the wet deposition in a semiarid region at San Luis Province, Argentina, were studied. Following these researches, in the same region, we have assessed the (7)Be content along a soil profile, during 2.5 years from September 2009 to January 2012. As expected, the specific activity values in soil samples in the wet period (November-April) were higher than in the dry period (May-October). During the investigated period (2009 - beginning 2012) and for all sampled points, the maximum value of the (7)Be specific activity (Bq kg(-1)) was measured at the surface level. A typical decreasing exponential function of (7)Be areal activity (Bq m(-2)) with soil mass depth (kg m(-2)) was found and the key distribution parameters were determined for each month. The minimum value of areal activity was 51 Bq m(-2) in August, and the maximum was 438 Bq m(-2) in February. The relaxation mass depth ranges from 2.9 kg m(-2) in March to 1.3 kg m(-2) in August. (7)Be wet deposition can explain in a very significant proportion the (7)Be inventory in soil. During the period of winds in the region (September and October), the (7)Be content in soil was greater than the expected contribution from wet deposition, situation that is compatible with a higher relative contribution of dry deposition at this period of the year.

Assessment of 7Be content in precipitation in a South American semi-arid environment.

There are two naturally occurring radiogenic isotopes of beryllium, 7Be and ¹°Be. These are produced when cosmic radiation interacts with oxygen and nitrogen in the atmosphere. After production, these radionuclides are input to ecosystems through wet and dry deposition. In recent years 7Be and ¹°Be have proved to be powerful tools for studying dynamic processes that occur on the surface of the earth. We measured the 7Be content in precipitation at a semiarid location in central Argentina. From November 2006 to March 2009, 68 precipitation events were collected. Measured 7Be content ranged from 0.7±0.4 Bq L⁻¹ to 3.2±0.7 Bq L⁻¹, with a mean of 1.7 Bq L⁻¹ ±0.6 Bq L⁻¹. Beryllium-7 content of rainfall did not show clear relationships with amount of rainfall (mm), mean intensity (mm h⁻¹) or duration (h⁻¹), or elapsed time between events (day). The general results indicate that for the typical range of precipitation there was no atmospheric washout and that the reload of the atmosphere is not a relevant factor, but when the amount of precipitation is very high washout may occur. On the other hand, when the 7Be content was measured during single rain events, a high content of this radionuclide was found to be associated with very low rainfall intensity (≈3 mm h⁻¹), this suggests that rain intensity could affect the 7Be content. Using all data, a good linear relationship between 7Be deposition and rain magnitude was obtained (r²=0.82, p<0.0001). Because of this, the slope of this linear regression equation may be applied as a tool for tracing environmental processes that affect the surface of the earth. We can do this by directly estimating erosion/sedimentation processes using 7Be or by estimating the input of ¹°Be in the environment with the aim to evaluate land degradation phenomena.

Short-term seasonal variability in 7Be wet deposition in a semiarid ecosystem of central Argentina.

The (7)Be wet deposition has been intensively investigated in a semiarid region at San Luis Province, Argentina. From November 2006 to May 2008, the (7)Be content in rainwater was determined in 58 individual rain events, randomly comprising more than 50% of all individual precipitations at the sampling period. (7)Be activity concentration in rainwater ranged from 0.7+/-0.3 Bq l(-1) to 3.2+/-0.7 Bq l(-1), with a mean value of 1.7 Bq l(-1) (sd=0.53 Bq l(-1)). No relationship was found between (7)Be content in rainwater and (a) rainfall amount, (b) precipitation intensity and (c) elapsed time between events. (7)Be ground deposition was found to be well correlated with rainfall amount (R=0.92). For the precipitation events considered, the (7)Be depositional fluxes ranged from 1.1 to 120 Bq m(-2), with a mean value of 32.7 Bq m(-2) (sd=29.9 Bq m(-2)). The annual depositional flux was estimated at 1140+/-120 Bq m(-2)y(-1). Assuming the same monthly deposition pattern and that the (7)Be content in soil decreases only through radioactive decay, the seasonal variation of (7)Be areal activity density in soil was estimated. Results of this investigation may contribute to a valuable characterization of (7)Be input in the explored semiarid ecosystem and its potential use as tracer of environmental processes.

Characterisation of uranium(VI) sorption by two environmental fungal species using gamma spectrometry.

Uranium(VI) sorption by two highly uranium-resistant air-borne fungi in a low-pH medium was measured by means of gamma spectrometry. Growth kinetics and stoichiometry of the two fungal species were also studied. Results show acceptable growth rates in synthetic medium with glucose and ammonia as carbon and nitrogen sources, respectively. Typical oxidative metabolism of carbohydrates was found. In vivo uptake of the radionuclide was negligible, but biosorption dry biomass presented a remarkable performance. The fungal strains showed potential for use in bioremediation.

210Pb dating of sediments in a heavily contaminated drainage channel to the La Plata estuary in Buenos Aires, Argentina.

Concentrations of (210)Pb and (137)Cs in sediment samples collected from two cores at a drainage channel to the La Plata river estuary in Buenos Aires, Argentina, were measured using ultralow-background detection systems. The (210)Pb data were used to determine the rate of sediment accumulation of the sites. These results were correlated with some heavy metal (chromium and lead) concentrations of the samples in an attempt to characterize the historical input of contaminants due to the industrial development, which has taken place in this area over the last century. The (137)Cs measurements demonstrate that cesium dating is not adequate in regions of the southern hemisphere.

Incidence of human papillomavirus infection in oral leukoplakia. Indications for a viral aetiology.

Epidemiological and experimental studies have indicated a possible role of human papillomavirus (HPV) in the etiopathogenesis of oral premalignant lesions and tumors. The aim of this study was to establish the incidence of HPV infection and the typing of genotypes in some patients with nonmalignant oral cavity pathology and healthy subjects. We selected 80 subjects affected by the following pathologies: oral leukoplakia (20), squamous cell papilloma (6), various forms of stomatitis (30), lichen planus (15), burning mouth syndrome (BMS, 9). Ten healthy subjects were used as control. The patients underwent a brushing directly on the lesion or on the lower gums and on the dorsal surface of the tongue and a new, sensitive method of in situ hybridization (ISH) with colorimetric signal amplification was used for HPV detecting. The samples were tested with a Mix probe, which identifies most of the HPV genotypes and, in positive cases, the specific probe for the 6-11, 31-33-51 and 16-18 genotypes, was used. Leukoplakia and papilloma were , therefore, associated with the HPV infection, differently from the other pathologies and healthy oral mucosa (chi-squared < 0.005). In conclusion, according to our findings, HPV is a specific risk factor for the development of oral premalignant lesions.

137Cs contamination in tea and yerba mate in South America.

Gamma-ray spectra from more than 50 samples of food products available in stores of Buenos Aires city were measured using a germanium detector. Activity concentrations of 137Cs up to 10 Bq/kg were found in tea and yerba mate manufactured in Apóstoles, Argentina. Further measurements of tea leaves, yerba mate leaves and soils, all coming from a cultivated area in that region, also show the presence of 137Cs contamination. The results suggest that the area was fertilized with a product that originated in a region affected by the fallout from the Chernobyl nuclear plant accident.

Oxidant stress and aspirin-insensitive thromboxane biosynthesis in severe unstable angina.

BACKGROUND: Unstable angina is associated with enhanced lipid peroxidation and reduced antioxidant defenses. We have previously reported aspirin failure in the suppression of enhanced thromboxane (TX) biosynthesis in a subset of episodes of platelet activation in this setting. We tested the hypothesis that the in vivo formation of the F(2)-isoprostane 8-iso-prostaglandin (PG)F(2alpha), a bioactive product of arachidonic acid peroxidation, is enhanced in unstable angina and contributes to aspirin-insensitive TX biosynthesis. METHODS AND RESULTS: Urine samples were obtained from patients with unstable angina (n=32), stable angina (n=32), or variant angina (n=4) and from 40 healthy subjects for the measurement of immunoreactive 8-iso-PGF(2alpha) and 11-dehydro-TXB(2). 8-Iso-PGF(2alpha) excretion was significantly higher in patients with unstable angina (339+/-122 pg/mg creatinine) than in matched patients with stable angina (236+/-83 pg/mg creatinine, P:=0.001) and control subjects (192+/-71 pg/mg creatinine, P:<0.0001). In patients with unstable angina, 8-iso-PGF(2alpha) was linearly correlated with 11-dehydro-TXB(2) excretion (rho=0.721, P:<0.0001) and inversely correlated with plasma vitamin E (rho=-0.710, P:=0. 004). Spontaneous myocardial ischemia in patients with variant angina or ischemia elicited by a stress test in patients with stable angina was not accompanied by any change in 8-iso-PGF(2alpha) excretion, thus excluding a role of ischemia per se in the induction of increased F(2)-isoprostane production. CONCLUSIONS: These findings establish a putative biochemical link between increased oxidant stress and aspirin-insensitive TX biosynthesis in patients with unstable angina and provide a rationale for dose-finding studies of antioxidants in this setting.

Multiple primary tumours in patients with oral squamous cell carcinoma.

A series of patients with oral squamous cell carcinoma (SCC) observed at the "Regina Elena" Cancer Institute was retrospectively reviewed in order to analyse the risk factors for multiple and second primary tumours (SPTs), their impact on survival and effective measures to control this phenomenon. In a survey of 200 individuals with a median follow-up of 3.2 years (25th percentile: 1.2, 75th percentile: 5.5), the incidence rate of SPTs was 14%: 39% arose in the oral cavity, 18% in the oropharynx, 10% in the lung and 7% both in the lip and larynx. There were no cases of secondary oesophageal tumours. Ninety-six per cent of the diagnosed histological types of SPTs were SCCs. Forty per cent of the new cancers were synchronous and 60% were metachronous, developing at a steady rate of 1.5% per year with no evidence of plateau. The overall incidence, adjusted by the length of follow-up, was 40 SPTs per 1000 person-years of follow-up. Although all the patients were at a greater risk for SPTs, the rates widely varied, according to specific factors: heavy tobacco consumption accounted for a statistically significant risk excess which was particularly high among younger smokers with an index tumour of the lower oral cavity. No difference was noticed in relation to the index neoplasm stage. In patients both with localised and advanced index tumours, 5-year survival rates were lower in those with SPTs and the difference was statistically significant for the 2-year survivors who were most likely to overcome the first disease. The present study confirms, the exceptionally high incidence of multifocal SCC in oral cancer patients and emphasizes the importance of preventive measures, since careful screening procedures, carried out to detect multifocal tumours at an early stage, should improve survival in these patients.

[Correlation between dietary vitamin A consumption and onset of precancerous lesions in the oral cavity]. / Correlazione tra consumo di vitamina A nella dieta e insorgenza di lesioni precancerose della cavità orale.

The efficacy of vitamin A in the prevention of oral cavity cancer has been studied during the last years due to the interest for a possible application of new drugs in the treatment of second primary tumours and multiple neoplasms. Fifty patients with oral precancerous lesions treated at the "Centre for prevention of oral cavity cancer" of the "Regina Elena" Institute in Rome, have been subjected to a rigorous questionnaire about their use of vitamin A in the diet. Moreover a standard sample of fifty healthy people without oral cavity lesions.

Relevance of heart rate as a prognostic factor in patients with acute myocardial infarction: insights from the GISSI-2 study.

AIMS: It is as yet undefined whether simple indexes of autonomic balance such as heart rate (HR) may play a role in risk stratification in patients with acute myocardial infarction (MI). The aim of this study was to quantify the prognostic significance of HR from the surface ECG obtained both at entry and at discharge, in a large population of patients all treated with fibrinolysis during the acute phase and having confirmed acute MI. METHODS AND RESULTS: Surface ECGs obtained at entry and at discharge in patients with confirmed MI enrolled in the GISSI-2 study, a large multicentre trial of different thrombolytic agents, were retrieved. Heart rhythm was evaluated and HR was measured; these data were then added to the main database of GISSI-2 allowing a complete evaluation of the prognostic significance of HR. Patients not in sinus rhythm or with grade 2-3 atrioventricular block were excluded. The prognostic significance of HR (cut-offs predefined at 60, 80, 100 beats.min-1) at entry for in-hospital mortality and at discharge for 6-month mortality was evaluated in the general population and in predefined subgroups. Multivariate analyses were used to assess the independent prognostic value of HR. A total of 8915 patients (more than 70% of the original population) were suitable for the analysis. There was a progressive increase in mortality with increasing HR in the general population (from 7.1% for HR < 60 beats.min-1) to 23.4% for HR > 100 beats.min-1) and in the predefined subgroups. Multivariate analysis showed that HR exerted an independent prognostic significance. Data for analysis of HR at discharge were available for 7831 patients. Consistent with the data observed at entry, a progressive increase of 6-month mortality with increasing HR was present in the general population (from 0.8% for HR < 60 beats.min-1) to 14.3% for HR > 100 beats.min-1) and for the different predefined subgroups. Multivariate analysis confirmed the independent prognostic significance of HR. There was no relation between HR and the incidence of fatal and non-fatal reinfarction. CONCLUSION: The present study indicates that HR values from a standard 12-lead ECG independently predict mortality in patients with acute MI during the in-hospital phase and after discharge. This simple index appears very useful for risk stratification in clinical practice.

Retinol dietary intake and oral leukoplakia development.

To investigate the clinical outcome of unbalanced diet in patients with oral precancerosis and to assess a possible relationship between dietary factors and the development of oral leukoplakia, a case-control study was carried out within a cohort of 53 subjects treated at our Centre in October-November 1997. Enrolled subjects and suitable controls underwent a careful interview on their own alimentary habits with a particular interest in retinol and carotenoids major sources. An individual qualitative and quantitative assessment of retinol-equivalents dietary intake, yielding average values for each group, allowed to compare the cohorts and to relate data also to tobacco use and to the severity of histopathological findings. Case levels were always significantly lower than controls (P<0.001), disregarding smoking, whilst no difference resulted between smokers and non smokers within the same groups. No statistical influence seemed to link alimentary vitamin A to the development of oral dysplasia but this work strengthen the epidemiological opinion that specific dietary factors are of great importance in oral oncology.

GFAP mRNA fluctuates in synchrony with chronic relapsing EAE symptoms in SJL/J mice.

Activation of astrocytes and hypertrophy of their processes is a result of a number of pathological conditions in the central nervous system. Astrocytic gliosis is especially prominent in multiple sclerosis (MS), where astrocytic fibers form a dense matrix around demyelinated axons. Experimental allergic encephalomyelitis (EAE), a laboratory model for MS, is also accompanied by astrocytic hyperactivity. We have previously shown the formation of plaque-like structures which stain heavily for glial fibrillary acidic protein (GFAP) in the brains and spinal cords of SJL/J mice after several episodes of chronic relapsing EAE (Smith and Eng: J Neurosci Res 18:203, 1987). To further investigate the mechanisms of this phenomenon, we have measured the levels of mRNA for GFAP throughout the course of three episodes and recoveries of EAE in the SJL/J mouse. Mice were immunized with spinal cord homogenate and subsequently developed EAE. After recovery they were again immunized at appropriate intervals, resulting in successive episodes of EAE, with partial or complete recovery between the paralytic stages. At appropriate times in the course of the different stages of EAE, spinal cords were dissected and RNA was prepared from each spinal cord. RNA was analyzed by Northern blots to determine the levels of mRNA for GFAP and, as a control for the 70 kDa neurofilament (NF-L). With the onset of the first EAE episode GFAP mRNA in spinal cords from animals with mild symptoms increased to sixfold the control level (P < 0.02) and to 20-fold in those with paralysis (P < 0.01).(ABSTRACT TRUNCATED AT 250 WORDS)

[False chorda tendinea of the left ventricle: possibility of diagnosis with echocardiography]. / Falsa corda tendinea del ventricolo sinistro: possibilità di diagnosi mediante ecocardiografia.

False tendons are fibrous strings that originate from the ventricular endocardium, but do not insert into the atrioventricular valve leaflets. Until recently these structures were recognized only at autopsy: recent reports have described some echocardiographic features of false tendons. In this paper we report our experience about false tendons in the left ventricle and some considerations on the echocardiographic differential diagnosis of these structures. In 4 of 1500 consecutive patients evaluated by M-mode and bidimensional echocardiography we have observed, throughout the cardiac cycle, an anomalous string-like linear echo stretched from the upper part of the interventricular septum to the apex (two cases) or to the lateral wall of the left ventricle (two cases). Associated cardiovascular diseases included mitral valve prolapse in two cases, systemic arterial hypertension in two cases and disturbances of cardiac rhythm in one case. Abnormal echoes in the left ventricular outflow tract are a common finding in several disorders such as discrete subaortic stenosis and aortic valve prolapse or vegetations. Furthermore a false tendon running parallel to the interventricular septum can mimick septal hypertrophy. Bidimensional echocardiographic examination, can identify these different conditions. Further studies will be necessary to firmly establish the diagnostic criteria of these structures at echocardiography.