The implications of crustal architecture and transcrustal upflow zones on the metal endowment of a world-class mineral district.

Earth's mineral deposits show a non-uniform spatial distribution from the craton-scale, to the scale of individual mineral districts. Although this pattern of differential metal endowment is underpinned by lithospheric-scale processes the geological features that cause clustering of deposits remains enigmatic. The integration of geological and geophysical (seismic, gravity, and magnetotelluric) features has produced the first whole-of-crust image through an iconic Neoarchean volcanic complex and mineral district in the Abitibi Greenstone Belt, Superior Province, Canada. Observations indicate an asymmetry in surface geology, structure, and crustal architecture that defines deep transcrustal magmatic-hydrothermal upflow zones and the limits of the Noranda District ore system. Here, extreme volcanogenic massive sulfide (VMS) endowment is confined to a smaller area adjacent to an ancestral transcrustal structure interpreted to have localized and optimized magmatic and ore forming processes. Although lithospheric-scale evolutionary processes might act as the fundamental control on metal endowment, the new crustal reconstruction explains the clustering of deposits on both belt and district scales. The results highlight a strong magmatic control on metal and in particular Au endowment in VMS systems. Overprinting by clusters of ca. 30 Ma younger orogenic Au deposits suggest the ore systems accessed an upper lithospheric mantle enriched in Au and metals.

Description of an outbreak of human trichinellosis in an area of Argentina historically regarded as Trichinella-free: the importance of surveillance studies.

Trichinellosis is an important food-borne zoonosis which is not treated as a major public health concern in Argentina. After more than 20 years without reports of infection in an area regarded as Trichinella-free, research studies reported that infection occurred in humans, pigs and game animals, including the recent outbreak of human trichinellosis revealed here. The outbreak, affecting 64 individuals, occurred in July 2010 in the province of Entre Ríos. Epidemiological studies, clinical observations, laboratory analyses and immunoserological specific assays (indirect immunofluorescence, IIF, and ELISA) were performed. Food samples were analyzed by artificial digestion, and Trichinella larvae isolates were identified to the species level by multiplex PCR. The main source of infection, commercially available food, had a parasite load of 1.1 muscle larvae per gram. Larvae were identified as Trichinella spiralis. Patients presented predominantly with oedema, fever and myalgia; and laboratory findings and/or immunoserological tests were positive for trichinellosis. Individuals received outpatient treatment. No deaths or secondary sequelae were recorded. Results suggest that the presence of T. spiralis infection should be suspected in all endemic areas, especially where animal husbandry and official food safety controls are not properly conducted. The lack of the cases reported ought not to be taken as a proof of parasite absence. We highlight the importance of the urgent need to implement interdisciplinary and inter-institutional programs aimed to control infection transmission, to guarantee food safety and to conduct epidemiological surveillance studies.

Use of digital video coronary arteriography in the performance of percutaneous transluminal coronary angioplasty.

Digital video coronary arteriography (DVCA) was used in 59 cases of percutaneous transluminal coronary angioplasty (PTCA) and found to be useful for display of imagery to facilitate choice of approach to a stenotic lesion; providing a "road map," simplifying guide wire manipulation and selective catheterization of vessels during PTCA; and archival of pre- and post-PTCA images. Use of DVCA for real-time display inside the catheterization laboratory expedites the successful performance of PTCA and is a convenient means of image archival.

Side branch occlusion complicating percutaneous transluminal coronary angioplasty.

A frequent concern during angioplasty is the possibility of occluding important side branches that originate in arterial stenoses subjected to balloon dilatation. The effect of dilatation on 93 side branches (greater than or equal to 1 mm in diameter) was evaluated in 86 patients undergoing percutaneous transluminal coronary angioplasty (PTCA) in whom those branches arose directly in dilated segments of the left anterior descending, circumflex, or right coronary arteries. Seventy-six of the 93 side branches had minor (less than 50%) narrowing at their origin. Among these side branches, nine (12%) were compromised by PTCA. Seventeen of the 93 side branches had greater than 50% ostial stenosis. Significantly more of these side branches (seven of seventeen, or 41%) were compromised by PTCA (P less than .01). Even when compromise does occur, it usually takes the form of increased stenosis rather than total occlusion. The presence of side branches originating in stenotic lesions is not a contraindication to PTCA since serious compromise of such branches rarely results from this procedure.

Dissection complicating angioplasty.

Extensive arterial dissection producing significant arterial obstruction or occlusion after technically uncomplicated percutaneous transluminal angioplasty in three patients is described. Despite the initially ominous arteriographic appearance, short-term (4-8 months) follow-up demonstrated complete resolution without surgical intervention. A trial of conservative management is recommended for this complication.