Pulmonary contusion in a collegiate diver: a case report

Abstract Introduction Pulmonary contusions typically occur after high-energy trauma and have rarely been reported as occurring during participation in sports. This is the first reported case of a pulmonary contusion occurring in a sport other than football. Case Presentation A 19-year-old Caucasian man impacted the water awkwardly after diving off a one-meter springboard. He complained of chest discomfort and produced immediate hemoptysis. Computed tomography confirmed the diagnosis of pulmonary contusion. The athlete recovered without complications and returned to activity one week after injury. Conclusion Immediate hemoptysis following blunt chest trauma during sports activity may indicate an underlying pulmonary contusion. No specific guidelines exist for return to athletic competition following pulmonary contusion, but a progressive return to activities once symptoms resolve appears to be a reasonable approach.</p

A Review of Dietary Zinc Recommendations

Background. Large discrepancies exist among the dietary zinc recommendations set by expert groups. Objective. To understand the basis for the differences in the dietary zinc recommendations set by the World Health Organization, the U.S. Institute of Medicine, the International Zinc Nutrition Consultative Group, and the European Food Safety Agency. Methods. We compared the sources of the data, the concepts, and methods used by the four expert groups to set the physiological requirements for absorbed zinc, the dietary zinc requirements (termed estimated and/or average requirements), recommended dietary allowances (or recommended nutrient intakes or population reference intakes), and tolerable upper intake levels for selected age, sex, and life-stage groups. Results. All four expert groups used the factorial approach to estimate the physiological requirements for zinc. These are based on the estimates of absorbed zinc required to offset all obligatory zinc losses plus any additional requirements for absorbed zinc for growth, pregnancy, or lactation. However, discrepancies exist in the reference body weights used, studies selected, approaches to estimate endogenous zinc losses, the adjustments applied to derive dietary zinc requirements that take into account zinc bioavailability in the habitual diets, number of dietary zinc recommendations set, and the nomenclature used to describe them. Conclusions. Estimates for the physiological and dietary requirements varied across the four expert groups. The European Food Safety Agency was the only expert group that set dietary zinc recommendations at four different levels of dietary phytate for adults (but not for children) and as yet no tolerable upper intake level for any life-stage group

Fin development in a cartilaginous fish and the origin of vertebrate limbs

Recent fossil finds and experimental analysis of chick and mouse embryos highlighted the lateral fin fold theory, which suggests that two pairs of limbs in tetrapods evolved by subdivision of an elongated single fin1. Here we examine fin development in embryos of the primitive cartilaginous fish, Scyliorhinus canicula (dogfish) using scanning electron microscopy and investigate expression of genes known to be involved in limb positioning, identity and patterning in higher vertebrates. Although we did not detect lateral fin folds in dogfish embryos, Engrailed-1 expression suggests that the body is compartmentalized dorso-ventrally. Furthermore, specification of limb identity occurs through the Tbx4 and Tbx5 genes, as in higher vertebrates. In contrast, unlike higher vertebrates, we did not detect Shh transcripts in dogfish fin-buds, although dHand (a gene involved in establishing Shh) is expressed. In S. canicula, the main fin axis seems to lie parallel to the body axis. 'Freeing' fins from the body axis and establishing a separate 'limb' axis has been proposed to be a crucial step in evolution of tetrapod limbs2, 3. We suggest that Shh plays a critical role in this process

Pyrite-induced hydroxyl radical formation and its effect on nucleic acids

BACKGROUND: Pyrite, the most abundant metal sulphide on Earth, is known to spontaneously form hydrogen peroxide when exposed to water. In this study the hypothesis that pyrite-induced hydrogen peroxide is transformed to hydroxyl radicals is tested. RESULTS: Using a combination of electron spin resonance (ESR) spin-trapping techniques and scavenging reactions involving nucleic acids, the formation of hydroxyl radicals in pyrite/aqueous suspensions is demonstrated. The addition of EDTA to pyrite slurries inhibits the hydrogen peroxide-to-hydroxyl radical conversion, but does not inhibit the formation of hydrogen peroxide. Given the stability of EDTA chelation with both ferrous and ferric iron, this suggests that the addition of the EDTA prevents the transformation by chelation of dissolved iron species. CONCLUSION: While the exact mechanism or mechanisms of the hydrogen peroxide-to-hydroxyl radical conversion cannot be resolved on the basis of the experiments reported in this study, it is clear that the pyrite surface promotes the reaction. The formation of hydroxyl radicals is significant because they react nearly instantaneously with most organic molecules. This suggests that the presence of pyrite in natural, engineered, or physiological aqueous systems may induce the transformation of a wide range of organic molecules. This finding has implications for the role pyrite may play in aquatic environments and raises the question whether inhalation of pyrite dust contributes to the development of lung diseases

Evaluating the use of 3'-(p-Aminophenyl) fluorescein for determining the formation of highly reactive oxygen species in particle suspensions

<p>Abstract</p> <p>Background</p> <p>Given the importance of highly reactive oxygen species (hROS) as reactants in a wide range of biological, photochemical, and environmental systems there is an interest in detection and quantification of these species. The extreme reactivity of the hROS, which includes hydroxyl radicals, presents an analytical challenge. 3'-(<it>p</it>-Aminophenyl) fluorescein (APF) is a relatively new probe used for measuring hROS. Here, we further evaluate the use of APF as a method for the detection of hydroxyl radicals in particle suspensions.</p> <p>Results</p> <p>Particle-generated hROS can be quantified with an estimated detection limit of 50 nM. Measurements of hROS in two National Institute of Standards and Technology (NIST 2709 and 2710) soil suspensions and a pyrite suspension show non-linear particle dose-response curves for hROS generation. APF can also be used in solutions containing no dissolved molecular oxygen (O₂) to determine the role of O₂in the formation of hROS. Results confirm that O₂is mechanistically important in the formation of hROS by dissolved ferrous iron and in pyrite suspensions.</p> <p>Conclusion</p> <p>Given the non-linear dose-response curves for particle generation of hROS, we recommend using several particle loadings in experiments aimed to compare particles for their hROS generation potential. The method presented here is specific to hROS and simple to perform. The analysis can be conducted in mobile labs as only basic laboratory equipment is required.</p

A demonstration of an affinity between pyrite and organic matter in a hydrothermal setting

One of the key-principles of the iron-sulphur world theory is to bring organic molecules close enough to interact with each other, using the surface of pyrite as a substrate in a hydrothermal setting. The present paper explores the relationship of pyrite and organic matter in a hydrothermal setting from the geological record; in hydrothermal calcite veins from Carboniferous limestones in central Ireland. Here, the organic matter is accumulated as coatings around, and through, pyrite grains. Most of the pyrite grains are euhedral-subhedral crystals, ranging in size from ca 0.1-0.5 mm in diameter, and they are scattered throughout the matrix of the vein calcite. The organic matter was deposited from a hydrothermal fluid at a temperature of at least 200°C, and gives a Raman signature of disordered carbon. This study points to an example from a hydrothermal setting in the geological record, demonstrating that pyrite can have a high potential for the concentration and accumulation of organic materials

Peripheral vasoconstriction influences thenar oxygen saturation as measured by near-infrared spectroscopy

Purpose: Near-infrared spectroscopy has been used as a noninvasive monitoring tool for tissue oxygen saturation (StO2) in acutely ill patients. This study aimed to investigate whether local vasoconstriction induced by body surface cooling significantly influences thenar StO2 as measured by InSpectra model 650. Methods: Eight healthy individuals (age 26 ± 6 years) participated in the study. Using a cooling blanket, we aimed to cool the entire body surface to induce vasoconstriction in the skin without any changes in central temperature. Thenar StO2 was noninvasively measured during a 3-min vascular occlusion test using InSpectra model 650 with a 15-mm probe. Measurements were analyzed for resting StO2 values, rate of StO2 desaturation (RdecStO2, %/min), and rate of StO2 recovery (RincStO2, %/s) before, during, and after skin cooling. Measurements also included heart rate (HR), mean arterial pressure (MAP), cardiac output (CO), stroke volume (SV), capillary refill time (CRT), forearm-to-fingertip skintemperature gradient (Tskin-diff), perfusion index (PI), and tissue hemoglobin index (THI). Results: In all subjects MAP, CO, SV, and core temperature did not change during the procedure. Skin cooling resulted in a significant decrease in StO2 from 82% (80-87) to 72% (70-77) (P\0.05) and in RincStO2 from 3.0%/s (2.8-3.3) to 1.7%/s (1.1-2.0) (P\0.05). Similar changes in CRT, Tskin-diff, and PI were also observed: from 2.5 s (2.0-3.0) to 8.5 s (7.2-11.0) (P\0.05), from 1.0 (-1.6-1.8) to 3.1 (P\0.05), and from 10.0% (9.1-11.7) to 2.5

Changes in microphytobenthos fluorescence over a tidal cycle: implications for sampling designs

Intertidal microphytobenthos (MPB) are important primary producers and provide food for herbivores in soft sediments and on rocky shores. Methods of measuring MPB biomass that do not depend on the time of collection relative to the time of day or tidal conditions are important in any studies that need to compare temporal or spatial variation, effects of abiotic factors or activity of grazers. Pulse amplitude modulated (PAM) fluorometry is often used to estimate biomass of MPB because it is a rapid, non-destructive method, but it is not known how measures of fluorescence are altered by changing conditions during a period of low tide. We investigated this experimentally using in situ changes in minimal fluorescence (F) on a rocky shore and on an estuarine mudflat around Sydney (Australia), during low tides. On rocky shores, the time when samples are taken during low tide had little direct influence on measures of fluorescence as long as the substratum is dry. Wetness from wave-splash, seepage from rock pools, run-off, rainfall, etc., had large consequences for any comparisons. On soft sediments, fluorescence was decreased if the sediment dried out, as happens during low-spring tides on particularly hot and dry days. Surface water affected the response of PAM and therefore measurements used to estimate MPB, emphasising the need for care to ensure that representative sampling is done during low tide

Tractable Fragments of Temporal Sequences of Topological Information

In this paper, we focus on qualitative temporal sequences of topological information. We firstly consider the context of topological temporal sequences of length greater than 3 describing the evolution of regions at consecutive time points. We show that there is no Cartesian subclass containing all the basic relations and the universal relation for which the algebraic closure decides satisfiability. However, we identify some tractable subclasses, by giving up the relations containing the non-tangential proper part relation and not containing the tangential proper part relation. We then formalize an alternative semantics for temporal sequences. We place ourselves in the context of the topological temporal sequences describing the evolution of regions on a partition of time (i.e. an alternation of instants and intervals). In this context, we identify large tractable fragments