Considerations When Diagnosing and Treating an Extra-Articular Fracture of Distal Radius Based on Plain Radiographs.

Background: The aim of this study was to investigate what should be considered when diagnosing and treating displaced extra-articular fractures based on plain radiographs. Methods: We included 181 extra-articular distal radius fractures with marked displacement requiring surgery, which were diagnosed with posteroanterior (PA) + lateral (Lat) + oblique views (obl). We compared the plain radiographs with CT scans to determine whether the diagnosis was properly made. We described the types of articular involvement incidentally found on CT scans and how the articular involvement was treated. We tested the inter-observer and intra-observer reliability with three orthopedic surgeons. Results: Forty-two (32%) out of 181 displaced extra-articular fractures diagnosed by plain radiographs had intra-articular involvement on CT scans. Dorso-ulnar intra-articular fragment was most commonly found. Thirty-three (78.6%) out of 42 intra-articular involvements required additional reduction and a dorsal approach was used in eight patients. Inter-observer and intra-observer reliability ranged from "substantial" to "almost perfect". Conclusions: When treating displaced extra-articular fractures requiring surgery, CT scans might be necessary to find intra-articular involvement and at least, an oblique view showing the dorso-ulnar corner of the articular surface should be added. Surgeons should consider that extra-articular fractures with marked displacement, which are diagnosed by plain radiographs alone, might have intra-articular involvement requiring additional reduction or fixation via a different incision.

Iron- and aluminium-induced depletion of molybdenum in acidic environments impedes the nitrogen cycle.

Anthropogenic nitrate contamination is a serious problem in many natural environments. Nitrate removal by microbial action is dependent on the metal molybdenum (Mo), which is required by nitrate reductase for denitrification and dissimilatory nitrate reduction to ammonium. The soluble form of Mo, molybdate (MoO4 2- ), is incorporated into and adsorbed by iron (Fe) and aluminium (Al) (oxy) hydroxide minerals. Herein we used Oak Ridge Reservation (ORR) as a model nitrate-contaminated acidic environment to investigate whether the formation of Fe- and Al-precipitates could impede microbial nitrate removal by depleting Mo. We demonstrate that Fe and Al mineral formation that occurs as the pH of acidic synthetic groundwater is increased, decreases soluble Mo to low picomolar concentrations, a process proposed to mimic environmental diffusion of acidic contaminated groundwater. Analysis of ORR sediments revealed recalcitrant Mo in the contaminated core that co-occurred with Fe and Al, consistent with Mo scavenging by Fe/Al precipitates. Nitrate removal by ORR isolate Pseudomonas fluorescens N2A2 is virtually abolished by Fe/Al precipitate-induced Mo depletion. The depletion of naturally occurring Mo in nitrate- and Fe/Al-contaminated acidic environments like ORR or acid mine drainage sites has the potential to impede microbial-based nitrate reduction thereby extending the duration of nitrate in the environment.

Metal reduction and iron biomineralization by a psychrotolerant Fe(III)-reducing bacterium, Shewanella sp. strain PV-4.

A marine psychrotolerant, dissimilatory Fe(III)-reducing bacterium, Shewanella sp. strain PV-4, from the microbial mat at a hydrothermal vent of Loihi Seamount in the Pacific Ocean has been further characterized, with emphases on metal reduction and iron biomineralization. The strain is able to reduce metals such as Fe(III), Co(III), Cr(VI), Mn(IV), and U(VI) as electron acceptors while using lactate, formate, pyruvate, or hydrogen as an electron donor. Growth during iron reduction occurred over the pH range of 7.0 to 8.9, a sodium chloride range of 0.05 to 5%, and a temperature range of 0 to 37 degrees C, with an optimum growth temperature of 18 degrees C. Unlike mesophilic dissimilatory Fe(III)-reducing bacteria, which produce mostly superparamagnetic magnetite (<35 nm), this psychrotolerant bacterium produces well-formed single-domain magnetite (>35 nm) at temperatures from 18 to 37 degrees C. The genome size of this strain is about 4.5 Mb. Strain PV-4 is sensitive to a variety of commonly used antibiotics except ampicillin and can acquire exogenous DNA (plasmid pCM157) through conjugation.