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1.
S Afr J Surg ; 61(2): 133-138, 2023 Jun.
Article in English | MEDLINE | ID: mdl-37381810

ABSTRACT

BACKGROUND: Trauma-induced coagulopathy (TIC) is a complex multifaceted process which contributes to higher mortality rates in severely injured trauma patients. Thromboelastography (TEG) is effective in detecting TIC which assists in instituting goal-directed therapy as part of damage control resuscitation. METHODS: This retrospective study included all adult patients over a 36-month period with penetrating abdominal trauma who required a laparotomy, blood products and admission for critical care. Analysis included demographics, admission data, 24-hour interventions, TEG parameters and 30-day outcomes. RESULTS: Eighty-four patients with a median age of 28 years were included. The majority (93%; 78/84) suffered from a gunshot injury, with 75% (63/84) receiving a damage control laparotomy. Forty-eight patients (57%) had a TEG. Injury severity score and total fluid and blood product administered in the first 24 hours were all significantly higher in patients who had a TEG (p < 0.05). TEG profiles were: 42% (20/48) normal, 42% (20/48) hypocoagulable, 12% (6/48) hypercoagulable and 4% (2/48) mixed parameters. Fibrinolysis profiles were: 48% (23/48) normal, 44% (21/48) fibrinolysis shutdown and 8% (4/48) hyperfibrinolysis. Mortality rate was 5% (4/84) at 24 hours and 26% (22/84) at 30 days, with no difference between the two groups. High-grade complication rates, days on a ventilator and intensive care unit length of stay were all significantly higher in patients who did not have a TEG. CONCLUSION: TIC is common in severely injured penetrating trauma patients. The usage of a thromboelastogram did not impact on 24-hour or 30-day mortality but did result in a decreased intensive care stay and a decreased high-grade complication rate.


Subject(s)
Abdominal Injuries , Thrombelastography , Adult , Humans , Retrospective Studies , Abdominal Injuries/diagnosis , Abdominal Injuries/surgery , Critical Care , Intensive Care Units
2.
Geochem Geophys Geosyst ; 17(2): 300-323, 2016 Feb.
Article in English | MEDLINE | ID: mdl-30123099

ABSTRACT

Rock and fluid samples were collected from three hydrothermal chimneys at the Endeavour Segment, Juan de Fuca Ridge to evaluate linkages among mineralogy, fluid chemistry, and microbial community composition within the chimneys. Mössbauer, midinfrared thermal emission, and visible-near infrared spectroscopies were utilized for the first time to characterize vent mineralogy, in addition to thin-section petrography, X-ray diffraction, and elemental analyses. A 282°C venting chimney from the Bastille edifice was composed primarily of sulfide minerals such as chalcopyrite, marcasite, and sphalerite. In contrast, samples from a 300°C venting chimney from the Dante edifice and a 321°C venting chimney from the Hot Harold edifice contained a high abundance of the sulfate mineral anhydrite. Geochemical modeling of mixed vent fluids suggested the oxic-anoxic transition zone was above 100°C at all three vents, and that the thermodynamic energy available for autotrophic microbial redox reactions favored aerobic sulfide and methane oxidation. As predicted, microbes within the Dante and Hot Harold chimneys were most closely related to mesophilic and thermophilic aerobes of the Betaproteobacteria and Gammaproteobacteria and sulfide-oxidizing autotrophic Epsilonproteobacteria. However, most of the microbes within the Bastille chimney were most closely related to mesophilic and thermophilic anaerobes of the Deltaproteobacteria, especially sulfate reducers, and anaerobic hyperthermophilic archaea. The predominance of anaerobes in the Bastille chimney indicated that other environmental factors promote anoxic conditions. Possibilities include the maturity or fluid flow characteristics of the chimney, abiotic Fe2+ and S2- oxidation in the vent fluids, or O2 depletion by aerobic respiration on the chimney outer wall.

3.
Geobiology ; 7(1): 35-49, 2009 Jan.
Article in English | MEDLINE | ID: mdl-19200145

ABSTRACT

Sediment samples were obtained from areas of diffuse hydrothermal venting along the seabed in the Tonga sector of the Tonga-Kermadec Arc, southwest Pacific Ocean. Sediments from Volcano 1 and Volcano 19 were analyzed by X-ray diffraction (XRD) and found to be composed primarily of the iron oxyhydroxide mineral, two-line ferrihydrite. XRD also suggested the possible presence of minor amounts of more ordered iron (hydr)oxides (including six-line ferrihydrite, goethite/lepidocrocite and magnetite) in the biogenic iron oxides (BIOS) from Volcano 1; however, Mössbauer spectroscopy failed to detect any mineral phases more crystalline than two-line ferrihydrite. The minerals were precipitated on the surfaces of abundant filamentous microbial structures. Morphologically, some of these structures were similar in appearance to the known iron-oxidizing genus Mariprofundus spp., suggesting that the sediments are composed of biogenic iron oxides. At Volcano 19, an areally extensive, active vent field, the microbial cells appeared to be responsible for the formation of cohesive chimney-like structures of iron oxyhydroxide, 2-3 m in height, whereas at Volcano 1, an older vent field, no chimney-like structures were apparent. Iron reduction of the sediment material (i.e. BIOS) by Shewanella putrefaciens CN32 was measured, in vitro, as the ratio of [total Fe(II)]:[total Fe]. From this parameter, reduction rates were calculated for Volcano 1 BIOS (0.0521 day(-1)), Volcano 19 BIOS (0.0473 day(-1)), and hydrous ferric oxide, a synthetic two-line ferrihydrite (0.0224 day(-1)). Sediments from both BIOS sites were more easily reduced than synthetic ferrihydrite, which suggests that the decrease in effective surface area of the minerals within the sediments (due to the presence of the organic component) does not inhibit subsequent microbial reduction. These results indicate that natural, marine BIOS are easily reduced in the presence of dissimilatory iron-reducing bacteria, and that the use of common synthetic iron minerals to model their reduction may lead to a significant underestimation of their biological reactivity.


Subject(s)
Ferric Compounds/chemistry , Geologic Sediments/chemistry , Hot Springs , Proteobacteria/metabolism , Oxidation-Reduction , Spectrum Analysis , Tonga , X-Ray Diffraction
4.
Appl Environ Microbiol ; 67(2): 827-33, 2001 Feb.
Article in English | MEDLINE | ID: mdl-11157250

ABSTRACT

With the submersible JAGO and by scuba diving we discovered three remarkable geothermal cones, rising 33, 25, and 45 m from the seafloor at a depth of 65 m in Eyjafjordur, northern Iceland. The greatest geothermal activity was on the highest cone, which discharged up to 50 liters of freshwater per s at 72 degrees C and pH 10.0. The cones were built up from precipitated smectite, formed by mixing of the hot SiO2-rich geothermal fluid with the cold Mg-rich seawater. By connecting a rubber hose to one outflow, about 240 liters of pure geothermal fluids was concentrated through a 0.2-microm-pore-size filter. Among 50 thermophilic isolates, we found members of Bacillus and Thermonema and a new unidentified low-G+C gram-positive member of the Bacteria as well as one member of the Archaea, Desulfurococcus mobilis. Analysis of small-subunit rRNA genes PCR amplified and cloned directly from environmental DNA showed that 41 out of 45 Bacteria sequences belonged to members of the Aquificales, whereas all of the 10 Archaea sequences belonged to the Korarchaeota. The physiological characteristics of isolates from different parts of the cones indicate a completely freshwater habitat, supporting the possibility of subterranean transmittance of terrestrial organisms.


Subject(s)
Bacteria/isolation & purification , Ecosystem , Gastrointestinal Agents/chemistry , Hot Temperature , Seawater , Silicates , Aluminum Silicates/chemistry , Bacteria/genetics , Bacteria/growth & development , Cloning, Molecular , DNA, Ribosomal/analysis , Genes, rRNA , Iceland , Magnesium/chemistry , Phylogeny , RNA, Ribosomal, 16S/genetics , Seawater/chemistry , Seawater/microbiology , Sequence Analysis, DNA
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