Assessment of radon risk areas in the Eastern Canary Islands using soil radon gas concentration and gas permeability of soils.

The Basic Safety Standard (BSS) Directive 2013/59/EURATOM of the European Union (EU) has stated the need for member states to establish national action plans to mitigate their general population's long-term risks of exposure to radon gas. Maps of radon-prone areas provide a useful tool for the development of such plans. This paper presents the maps of radon-prone areas in the Eastern Canary Islands (Gran Canaria, Fuerteventura and Lanzarote) obtained from assessment of Geogenic Radon Potential (GRP) distribution in the territory. GRP constitutes a magnitude that is contingent on both radon activity concentration and gas permeability of soils. An extensive campaign covering all geological formations of the Eastern Canary Islands was undertaken to locally sample these parameters. Geostatistical analysis of the spatial distribution of radon concentration in soils, permeability and GRP was performed on each of the islands, and the relationship between these magnitudes and the characteristic geological formations of the volcanic islands was investigated. Areas dominated by basic volcanic and plutonic rocks (originated by both recent and ancient volcanism) exhibit relatively low levels of radon in soils, and with the exception of specific cases of very high permeability, these areas are not classified as prone to radon risk according to international criteria. Areas in which intermediate or acidic volcanic and plutonic rocks predominate are characterised by greater radon activity concentration in soils, rendering them radon-prone. Given these results, Lanzarote is classified as an island with low radon risk all over its surface; Fuerteventura presents low-medium risk; and Gran Canaria contains extensive areas in the centre and north where the risk is medium or high. This classification is consistent with the risk maps obtained by National and European agencies from indoor radon measurements conducted on these islands.

A simple methodology for characterization of germanium coaxial detectors by using Monte Carlo simulation and evolutionary algorithms.

The determination in a sample of the activity concentration of a specific radionuclide by gamma spectrometry needs to know the full energy peak efficiency (FEPE) for the energy of interest. The difficulties related to the experimental calibration make it advisable to have alternative methods for FEPE determination, such as the simulation of the transport of photons in the crystal by the Monte Carlo method, which requires an accurate knowledge of the characteristics and geometry of the detector. The characterization process is mainly carried out by Canberra Industries Inc. using proprietary techniques and methodologies developed by that company. It is a costly procedure (due to shipping and to the cost of the process itself) and for some research laboratories an alternative in situ procedure can be very useful. The main goal of this paper is to find an alternative to this costly characterization process, by establishing a method for optimizing the parameters of characterizing the detector, through a computational procedure which could be reproduced at a standard research lab. This method consists in the determination of the detector geometric parameters by using Monte Carlo simulation in parallel with an optimization process, based on evolutionary algorithms, starting from a set of reference FEPEs determined experimentally or computationally. The proposed method has proven to be effective and simple to implement. It provides a set of characterization parameters which it has been successfully validated for different source-detector geometries, and also for a wide range of environmental samples and certified materials.

Recognition of melanoma cell antigens with antibodies present in sera from patients with vitiligo.

BACKGROUND: Patients with vitiligo show specific losses of integumentary melanocytes, probably due to autoimmunity against melanocytes. We attempted to determine the presence of antibodies against pigment cell antigens in the sera of vitiligo patients. METHODS: Detergent-solubilized human melanoma cells were submitted to electrophoretic separation and immunoblotted against serum samples obtained from 19 patients with vitiligo and from 20 age- and sex-matched healthy individuals. RESULTS: Eighty-nine per cent of patients with vitiligo had antibodies to one or more pigment cell antigens. Similar antibodies were detected in 20% of healthy individuals. Antigens of 165, 90, and 68 kDa were recognized by the antibodies present in sera from 11%, 26%, and 37% of vitiligo patients, respectively, and in none of the normal sera. All patients with familial vitiligo also had antibodies to these three proteins. CONCLUSIONS: Proteins of 165, 90, and 68 kDa are specifically recognized by antibodies present in the sera of vitiligo patients and in all patients with genetic vitiligo. Whether or not these proteins might be implicated in the destruction of melanocytes by the immune system in vitiligo remains to be evaluated.

Ivermectin for human strongyloidiasis and other intestinal helminths.

Since ivermectin, a mixture of 2 closely related macrocyclic lactones, has proven highly effective against animal intestinal nematodes, trials were undertaken to determine its efficacy against human intestinal nematodes. We tested 110 patients with strongyloidiasis and 90 with enterobiasis; many had other intercurrent intestinal nematode infections. Stool examinations were done before and after patients were given a single dose of oral ivermectin capsules (50, 100, 150, or 200 micrograms/kg body wt); 55 recipients of 100 or 200 micrograms/kg doses received a second identical dose the next day. Kato and saline smears, ethyl acetate concentration, modified Baermann's technique, and Harada-Mori cultures were repeated; cure was defined as complete absence of eggs and/or larvae from stools tested 30 days after dosing. Ivermectin was well tolerated. Overall cure rates at all doses 30 days after therapy averaged 88% for strongyloidiasis, 100% for ascariasis, 85% for trichuriasis, and 85% for enterobiasis. Ancylostoma duodenale and Necator americanus were little affected.

Use of norfloxacin to treat chronic typhoid carriers.

High relapse rates and low tolerability to ampicillin characterize present therapy for carriers of Salmonella typhi. Norfloxacin, a carboxyquinolone with a 90% minimum inhibitory concentration for S. typhi of less than or equal to 0.5 micrograms/mL, is a promising alternative. Carriers of S. typhi were treated in a double-blind trial with either norfloxacin (400 mg) or matching placebo given every 12 h for 28 d. Twelve assessable individuals were treated in each group. After therapy, 11 of 12 individuals treated with norfloxacin had negative stool and bile cultures for S. typhi. All placebo-treated carriers still had positive cultures immediately after therapy. Subsequently, 11 individuals were treated openly with norfloxacin. S. typhi was eradicated in seven of 11. Overall, the eradication rate for 23 individuals treated with norfloxacin was 78%. Eighteen individuals were followed up for one year, and their stool and/or bile cultures remained negative. From our results, norfloxacin is an effective and well-tolerated antimicrobial agent for eradicating the chronic typhoid carrier state.

Brucellar arthritis: a study of 39 Peruvian families.

A study was conducted to characterise the articular manifestation of Brucella melitensis within a family in Peru. From January 1981 to June 1986, 39 families with 232 individuals were evaluated. Brucellosis was diagnosed in 118 family members (attack rate of 50.9%). A lower attack rate was observed in children less than 10 years' old compared with other age groups (p less than 0.02). Complete clinical data were available in 92 of the 118 affected members. Moderate and severe forms of the diseases were more prevalent in women than in men (41.8% v 13.5%; p less than 0.001). Twenty eight of the 92 patients developed some brucellar complications; the articular involvement was the most prevalent (23.9%). Arthritis was also more common in women than in men (34.5% v 8.1%; p less than 0.01). Children appeared to have less articular involvement. Overall, the following pattern was observed: peripheral arthritis (54.5%); unilateral sacroiliitis (23.0%); mixed arthritis (4.5%), and spondylitis (9.1%). Spondylitis was seen only in the elderly with chronic brucellosis. Four patients developed extra-articular rheumatism. Within members of family groups, brucellar arthritis occurred less frequently than in individual patients from the same hospital. This suggests that many family cases were diagnosed in the early stages.

Imipenem/cilastatin vs. gentamicin/clindamycin for the treatment of moderate to severe infections in hospitalized patients.

Imipenem/cilastatin was compared with the combination of gentamicin plus clindamycin in terms of efficacy and safety for the treatment of moderate to severe infections in an open, randomized study. The rates of cure achieved with the two regimens were similar. Gentamicin/clindamycin treatment failed only in two of four instances of severe infection. Patients given imipenem/cilastatin seemed to respond more rapidly to treatment; this observation applied both to the entire group treated and to the subgroup with moderate intraabdominal infections. Susceptible etiologic agents were more frequently eradicated by imipenem/cilastatin (95%) than by gentamicin/clindamycin (79%). The most common adverse reactions were nausea or vomiting in patients given imipenem/cilastatin and urinary abnormalities in those given gentamicin/clindamycin. Self-limited diarrhea was observed with equal frequency in the two groups. No adverse reactions required the discontinuation of treatment. Colonization or superinfection with resistant organisms and Pseudomonas aeruginosa occurred significantly more often among patients given gentamicin/clindamycin. These results suggest that imipenem/cilastatin is a promising alternative to the combination of gentamicin and clindamycin for the treatment of moderate to severe infections in hospitalized patients.

Clinical evaluation of norfloxacin versus cotrimoxazole in urinary tract infections.

Forty patients with urinary tract infections were randomly assigned to receive a ten-day course of oral therapy with either norfloxacin 400 mg twice daily or cotrimoxazole (trimethoprim-sulfamethoxazole) 160/800 mg twice daily. There were 34 cases (19 in the norfloxacin and 15 in the cotrimoxazole group) of evaluable infections due to Escherichia coli (85% of cases), Klebsiella pneumoniae, Enterobacter spp., Proteus vulgaris and Alcaligenes faecalis. All organisms were sensitive to the assigned study drug. Twenty-two strains of Escherichia coli and five other isolates had a norfloxacin MIC50 of 0.03 mg/l and MIC90 of 1.0 mg/l. All patients were cured of the initial infection. Three diabetic patients in the norfloxacin group and another healthy patient in the cotrimoxazole group experienced asymptomatic recurrences due to organisms of the same species which, in the absence of causes of bacterial persistence, were considered to be reinfections. Mild reversible adverse effects of no clinical significance were observed in nine patients in each treatment group. Norfloxacin seems to be as effective and safe as cotrimoxazole in the conventional treatment of uncomplicated urinary tract infection.