Reproducible responses of geochemical and microbial successional patterns in the subsurface to carbon source amendment

Carbon amendments designed to remediate environmental contamination lead to substantial perturbations when injected into the subsurface. For the remediation of uranium contamination, carbon amendments promote reducing conditions to allow microorganisms to reduce uranium to an insoluble, less mobile state. However, the reproducibility of these amendments and underlying microbial community assembly mechanisms have rarely been investigated in the field. In this study, two injections of emulsified vegetable oil were performed in 2009 and 2017 to immobilize uranium in the groundwater at Oak Ridge, TN, USA. Our objectives were to determine whether and how the injections resulted in similar abiotic and biotic responses and their underlying community assembly mechanisms. Both injections caused similar geochemical and microbial succession. Uranium, nitrate, and sulfate concentrations in the groundwater dropped following the injection, and specific microbial taxa responded at roughly the same time points in both injections, including Geobacter, Desulfovibrio, and members of the phylum Comamonadaceae, all of which are well established in uranium, nitrate, and sulfate reduction. Both injections induced a transition from relatively stochastic to more deterministic assembly of microbial taxonomic and phylogenetic community structures based on 16S rRNA gene analysis. We conclude that geochemical and microbial successions after biostimulation are reproducible, likely owing to the selection of similar phylogenetic groups in response to EVO injection.

Prevalence of Pain With Movement in Active Duty US Army Soldiers

INTRODUCTION

Soldiers must be able to perform a multitude of physically demanding tasks as part of their regular duty, but their physical readiness is often degraded due to pain and musculoskeletal injury (MSKI). The presence of pain with movement has been associated with increased MSKI risk in Soldiers. Improved awareness of the prevalence of painful movements in uninjured Soldiers could help inform Army injury mitigation efforts. The purpose of this study was to identify the prevalence of pain with movement in a population of healthy active duty Soldiers.

MATERIALS AND METHODS

The Selective Functional Movement Assessment-Top Tier Movements (SFMA-TTM), active range of motion (AROM) of the hips and shoulders, and the elicitation of pain with movement were measured in 268 healthy US Army Soldiers. Descriptive statistics were generated for the number of painful movements for each measure and inferential statistics; independent t-test and one-way independent analysis of variance (ANOVA) were used for analysis of the other measures.

RESULTS

Greater than half (59%) of the participants reported pain with at least 1 movement and more than 41% reported pain with 2 or more movements. Soldiers reported a mean of 1.35 painful movements on the SFMA-TTM assessment and a mean of 1.54 painful AROM movements.

CONCLUSIONS

Pain with functional movement patterns was common across a sample of uninjured Soldiers. The presence of pain with movement warrants further evaluation as it may impact a Soldier's physical performance, risk for future injury, and overall quality of life.

Timing of Outcomes and Expectations After Knee Surgery in the US Military: A Systematic Review

CONTEXT

Knee injury and subsequent surgery are widespread in the military setting. Associations between knee surgery and expected outcomes over time have not been consolidated and characterized systematically by procedure type across the body of literature, and the temporal expectations of these outcomes remain unclear.

OBJECTIVE

To summarize common postoperative follow-up times and associated outcomes that determine clinical or surgical failure in US service members after elective knee surgery.

DATA SOURCES

A systematic search was conducted with 3 bibliographic databases of published research reports from 2010 through 2021.

STUDY SELECTION

Studies in US military service members undergoing elective knee surgery, with a minimum of 1-year follow-up, and reporting on a functional/occupational outcome were included. Three reviewers screened all abstracts and full-text articles to determine eligibility.

STUDY DESIGN

Systematic review of longitudinal cohort studies.

LEVEL OF EVIDENCE

Level 2a.

DATA EXTRACTION

Extracted data included military demographics, surgical procedure variables, surveillance period, and outcome measures. The Newcastle-Ottawa Scale and the Grading of Recommendations Assessment, Development, and Evaluation approach were used to determine study quality and risk of bias.

RESULTS

A total of 22 studies (mean follow-up time of 40.7 months) met the inclusion criteria. For cruciate ligament repair, approximately one-third of patients required a second surgery or were medically separated from military service by 2 years from surgery; 100% were reinjured by 4 years, and 85% sustained a new injury within 5 years of surgery. For meniscal repair, nearly one-third of patients were medically separated, and half were placed on activity restrictions within 3 years of surgery. For articular cartilage repair, within 5 years, 39% of patients required a second surgery, 30% were placed on activity restrictions, and 36% were medically separated. For patellar repair, 37% of patients were medically separated and over half were placed on activity restrictions within 5 years.

CONCLUSION

Common knee surgeries can have long-term implications for military careers that may not become apparent with shorter follow-up periods (<2 years). When longer surveillance periods are used (eg, up to 5 years), additional surgical procedures are more common and the likelihood of being injured or medically separated from military service is higher.

Predicting Postoperative Injury and Military Discharge Status After Knee Surgery in the US Army

BACKGROUND

Researchers have assessed postoperative injury or disability predictors in the military setting but typically focused on 1 type of surgical procedure at a time, used relatively small sample sizes, or investigated mixed cohorts with civilian populations.

PURPOSE

To identify the relationship between baseline variables and injury incidence or military discharge status in US Army soldiers after knee surgery.

STUDY DESIGN

Case-control study; Level of evidence, 3.

METHODS

Data were obtained from a repository containing personnel, performance, and medical records for all active-duty US Army soldiers. Multivariate logistic regressions were used to estimate the effects of numerous variables on postoperative injury or on medical discharge. Variable selection and model validation were conducted using the k-fold method.

RESULTS

A total of 7567 soldiers underwent knee surgery between 2017 and 2019. Meniscal procedures were the most common type of surgery (39%), and approximately 71% of the cohort had a postoperative injury. Significant predictors for sustaining a postoperative injury included having a previous nonknee injury (odds ratio [OR], 1.5), female sex (OR, 1.3), and Black race (OR, 1.2). Within 4 years after surgery, 17% of soldiers were discharged from the military because of knee-related disability. Significant predictors for discharge from duty included enlisted rank (OR, 2.3), recent fitness test failure (OR, 1.9), number of previous knee surgeries (OR, 1.7), and having a previous nonknee injury (OR, 1.6).

CONCLUSION

After knee surgery, nearly three-fourths of the soldiers in this cohort sustained a postoperative injury and almost one-fifth of soldiers were medically discharged from the military within 4 years. This study identified variables that indicate statistically increased risk for these postoperative outcomes and highlighted potentially modifiable factors.

Upper Extremity Superficial Vein Thromboses Presenting as Acute Neck Pain in a Young and Healthy Male: A Case Report

BACKGROUND AND PURPOSE

Neck pain in the United States is pervasive and contributes to disability. While the majority of neck pain in young and healthy individuals is neuromusculoskeletal in nature, screening for red flags is necessary for ruling-out serious medical pathologies. The purpose of this case report is to describe a young and healthy male subject with a primary complaint of acute neck pain with multiple underlying upper extremity superficial vein thromboses (UESVTs).

CASE DESCRIPTION

The subject was a 27-year-old male active-duty Soldier referred to physical therapy by his primary care provider (PCP) for acute left-sided neck pain. Prior to physical therapy, the subject had been treated with cyclobenzaprine, oxycodone-acetaminophen, trigger point injection and had undergone a D-dimer to rule out a potential thrombus due to air travel and lower extremity immobilization.

OUTCOMES

The subject underwent a D-dimer, Doppler ultrasound, pharmacological treatment of Rivaroxaban, and was referred to hematology/oncology to rule out systemic causes of SVTs. Evidence of subtle increases in blood pressure over the course of three months, a positive D-dimer, and symptoms incongruent with clinical presentation contributed to referral to a hematology/oncology specialist and a diagnosis of multiple UESVTs. The subject was able to return to his previous level of activity by six months and remained free of SVTs at two-year follow-up.

DISCUSSION

UESVT events are rare and can be challenging to identify. This case report describes a unique presentation of acute neck pain caused by underlying UESVTs in an otherwise healthy and active young male.

LEVEL OF EVIDENCE

Level 4.

Characterization of subsurface media from locations up- and down-gradient of a uranium-contaminated aquifer

The processing of sediment to accurately characterize the spatially-resolved depth profiles of geophysical and geochemical properties along with signatures of microbial density and activity remains a challenge especially in complex contaminated areas. This study processed cores from two sediment boreholes from background and contaminated core sediments and surrounding groundwater. Fresh core sediments were compared by depth to capture the changes in sediment structure, sediment minerals, biomass, and pore water geochemistry in terms of major and trace elements including pollutants, cations, anions, and organic acids. Soil porewater samples were matched to groundwater level, flow rate, and preferential flows and compared to homogenized groundwater-only samples from neighboring monitoring wells. Groundwater analysis of nearby wells only revealed high sulfate and nitrate concentrations while the same analysis using sediment pore water samples with depth was able to suggest areas high in sulfate- and nitrate-reducing bacteria based on their decreased concentration and production of reduced by-products that could not be seen in the groundwater samples. Positive correlations among porewater content, total organic carbon, trace metals and clay minerals revealed a more complicated relationship among contaminant, sediment texture, groundwater table, and biomass. The fluctuating capillary interface had high concentrations of Fe and Mn-oxides combined with trace elements including U, Th, Sr, Ba, Cu, and Co. This suggests the mobility of potentially hazardous elements, sediment structure, and biogeochemical factors are all linked together to impact microbial communities, emphasizing that solid interfaces play an important role in determining the abundance of bacteria in the sediments.

Small and mighty: adaptation of superphylum Patescibacteria to groundwater environment drives their genome simplicity

BACKGROUND

The newly defined superphylum Patescibacteria such as Parcubacteria (OD1) and Microgenomates (OP11) has been found to be prevalent in groundwater, sediment, lake, and other aquifer environments. Recently increasing attention has been paid to this diverse superphylum including > 20 candidate phyla (a large part of the candidate phylum radiation, CPR) because it refreshed our view of the tree of life. However, adaptive traits contributing to its prevalence are still not well known.

RESULTS

Here, we investigated the genomic features and metabolic pathways of Patescibacteria in groundwater through genome-resolved metagenomics analysis of > 600 Gbp sequence data. We observed that, while the members of Patescibacteria have reduced genomes (~ 1 Mbp) exclusively, functions essential to growth and reproduction such as genetic information processing were retained. Surprisingly, they have sharply reduced redundant and nonessential functions, including specific metabolic activities and stress response systems. The Patescibacteria have ultra-small cells and simplified membrane structures, including flagellar assembly, transporters, and two-component systems. Despite the lack of CRISPR viral defense, the bacteria may evade predation through deletion of common membrane phage receptors and other alternative strategies, which may explain the low representation of prophage proteins in their genomes and lack of CRISPR. By establishing the linkages between bacterial features and the groundwater environmental conditions, our results provide important insights into the functions and evolution of this CPR group.

CONCLUSIONS

We found that Patescibacteria has streamlined many functions while acquiring advantages such as avoiding phage invasion, to adapt to the groundwater environment. The unique features of small genome size, ultra-small cell size, and lacking CRISPR of this large lineage are bringing new understandings on life of Bacteria. Our results provide important insights into the mechanisms for adaptation of the superphylum in the groundwater environments, and demonstrate a case where less is more, and small is mighty.

Effects of pattern, spatial frequency, number, and rate of stimulus presentation on the accuracy of detection

Brief trains of pulsed stimuli were used to assess whether magnocellular or parvocellular visual pathways could be differentiated perceptually. Trains of either one to four sine-wave, square-wave, or checkerboard gratings were presented at three temporal and two spatial frequencies to six observers. The task of the observer was to report the perceived number of stimuli (gratings) in a train. The difference between actual number and perceived number of gratings was recorded as an error score. It was found that neither the pattern nor the spatial frequency of the gratings significantly affected perceptual accuracy. On the other hand, the number of gratings in a train and the interstimulus interval between gratings produced significant differences. Perceptual accuracy was greater when lower numbers of gratings in a train were presented with longer interstimulus intervals. The observers typically reported fewer stimuli than were presented. The source of the discrepancy is discussed in terms of a light adaptive process initiated in the retina.

Intra-arterial chemotherapy given preoperatively in the management of carcinoma of the stomach

Intra-arterial chemotherapy has been used preoperatively in treating patients with carcinoma of the stomach. The chemotherapy was given continuously for about one month with gastrectomy planned for three to four weeks after completion of chemotherapy. The agents used were 5-fluorouracil, Adriamycin (doxorubicin hydrochloride) and mitomycin C. The objective was to reduce the size and extent of the disease prior to subsequent surgical resection. Most of the patients had a partial response to the chemotherapy infusion. Two patients had an apparent complete response. For 16 patients who presented with the most advanced lesions, initially considered to be incurable, some palliation was achieved but long term results were not significantly changed. For 17 patients with locally invasive disease which would normally have been treated by gastrectomy alone, with an expectation of about 10 per cent five year survival time, long term results appear to have been significantly improved.

Hand carriage of aerobic gram-negative rods may not be transient

In order to determine whether hand carriage of aerobic Gram-negative rods is continuous we used the glove-handwash technique to sample the hands of two groups (four each) of health care workers with normal hands (surgical intensive care unit, medical ward) and one group (four) with hand dermatitis (HD) and a group (five) of control subjects -- secretaries with no exposure to patients. Each subject was sampled repeatedly over three to six weeks. The mean number of samples for each group was 25.2, 23.2, 19.8 and 25.8 respectively. The HD group had more samples positive for aerobic Gram-negative rods than did the other two groups of health care workers while the control group had more samples positive than any of the three health care groups. Using various typing schemes and the following definition of continuous carriage (the isolation of an organism of the same serotype, pyocin type or biotype from more than two handwash samples) we found that 4 of 11 subjects from whom Klebsiella pneumoniae was isolated carried this organism continuously; 2 of 3 carried Pseudomonas aeruginosa continuously and 4 of 5 of the control subjects carried the same biotype of Enterobacter agglomerans continuously. We conclude that continuous hand carriage of aeroic Gram-negative rods is common and, among health care workers, those with hand dermatitis carry Gram-negative rods more frequently and in greater numbers than health care workers without hand dermatitis.

Hand carriage of aerobic Gram-negative rods by health care personnel

A quantitative culture technique (hand washed in a glove containing broth for 30 s) was used to determine the frequency of hand carriage of aerobic Gram-negative rods by various groups of health care workers and 104 control subjects. Overall, 31% of health care workers carried aerobic Gram-negative rods on their hands compared to 59% of control subjects (P < 0.001). Enterobacter agglomerans accounted for 40% of the isolates, and other Enterobacter spp. 7%. Other organisms included Acinetobacter calcoaceticus 21%, Serratia spp. 11%, Klebsiella spp. 10%, Moraxella spp. 3%, Pseudomonas spp. 3%, Proteus spp. 1.5%, Escherichia coli 1%; Morganella morganii, Citrobacter freundii, Aeromonas sp. and an isolate that was not speciated accounted for 0.5% each. We conclude that endemic hand carriage of aerobic Gram-negative rods by health care personnel is common, but significantly less than that of control subjects. Enterobacter agglomerans is found so frequently on the hands of control subjects that it must be considered part of the normal hand flora.

Induction and genetics of two alpha-galactosidase activities in Saccharomyces cerevisiae

The induction of alpha-galactosidase of Saccharomyces cerevisiae was investigated. We have demonstrated the existence of inducible internal and external alpha-galactosidase activities and have studied the relationship between the two alpha-galactosidases by examining a mutant strain which lacks both the internal and external activities. The mutant possesses a mutation in a single locus (mel1-1) which does not affect the synthesis of the other galactose pathway enzymes or the ability of the yeast to grow on media containing only galactose as the carbon source. Genetic studies of the mutant indicate that mel 1-1 is recessive and allelic to the wild tye allele for melibiose fermentation Mel 1.

Dilution kinetic studies of yeast populations: in vivo aggregation of galactose utilizing enzymes and positive regulator molecules

By use of a selective medium containing ethidium bromide, population analyses of yeast galactose long-term adaptation mutants (gal3) in the process of deadaptation in the absence of galactose have been performed. The analysis of diploid strains homozygous for the gal3 locus but heterozygous for different combinations of the other mutant galactose loci, which thus have reduced amounts of the gene products of those loci, have demonstrated that, in addition to the two permease units determined in a previous study, a cell requires one complex of the Leloir pathway enzymes and two complexes specified by the Gal4 locus to be readily induced. From the consideration of these complexes as being aggregated molecules which are diluted out as units (i.e., if such a molecule were a dimer, it would not dissociate into monomers) during cell growth, the in vivo aggregation of these enzymes and the Gal4 gene product could be studied. The data indicate that the function of the Gal4 gene product is to activate a Leloir enzyme complex. It is postulated that the gal3 phenotype is the result of such strains' inability to actively synthesize an endogenous co-inducer which allows wild-type cells to be readily induced upon exposure to galactose.

Population analysis of the deinduction kinetics of galactose long-term adaptation mutants of yeast

By use of a selective galactose agar medium containing ethidium bromide, a population analysis of the deinduction kinetics of yeast galactose long-term adaptation mutants (gal 3) has been done. It was first determined that the gal 3 mutation is specific to the yeast galactose system and that induced cultures of gal 3 strains are capable of growth on galactose agar medium containing ethidium bromide, whereas noninduced cultures are not. Population analyses of induced gal 3 strains under going deinduction in the absence of galactose demonstrate that a minimum number of five induction units per cell are required for induction of the galactose system. It is concluded that: these induction units are actively synthesized only in the presence of inducer and are diluted out through cell division; they are stable under nongrowing conditions; they are heterogeneous in nature; at most two of the five minimum units are products of the gal 2 locus; and the other units may be three of one type, one of one type and two of another, or one each of three different types.

Induction of galactokinase in Saccharomyces cerevisiae: kinetics of induction and glucose effects

The induced synthesis of galactokinase and the repressing effects of glucose on this synthesis have been investigated in whole yeast cells rendered permeable by treatment with dimethyl sulfoxide. It was found that the induction response of uninduced cells to galactose is clearly dependent on the nature of the carbon source upon which the culture was grown prior to exposure to galactose. Glucose-grown cells exhibited a long lag before induction, whereas lactate-grown cells exhibited induced synthesis within 8 min. A concentration of 0.5% galactose was found to be optimal for induction. The addition of glucose to yeast cultures growing on galactose resulted in a severe transient repression of synthesis which was followed by a resumed rate of synthesis characteristic of a weaker permanent catabolite repression. Neither 2-deoxygalactose nor fucose acted as gratuitous inducers of the pathway, nor did they serve as a substrates for galactokinase.

Differential effect of respiratory inhibitors on ergosterol synthesis by Saccharomyces cerevisiae during adaptation to oxygen

The effect of different respiratory inhibitors on the ergosterol content of microaerobically grown non-proliferating yeast cultures was monitored during adaptation to oxygen. It was found that dinitrophenol, azide, and cyanide, which act on the mechanism of the respiratory chain, cause a marked stimulation of sterol production. Acriflavine and chloramphenicol, which affect the synthesis of the respiratory apparatus, caused a delay in the onset of ergosterol synthesis or a marked decrease in sterol content. The data obtained provide presumptive evidence that a component of sterol formation is synthesized on the 70S ribosomal system of the mitochondrion and induced in the presence of oxygen.

Isolation from yeast of a metabolically active water-soluble form of ergosterol

A water-soluble complex containing ergosterol together with a component of yeast has been isolated. The complex can be isolated from commercial yeast extract to which ergosterol has been added or directly from whole yeast cells. The complexing component has the properties of a large polysaccharide and the binding between the sterol and the polysaccharide appears to be noncovalent. The complex is easily prepared and is stable in aqueous solution; ergosterol in this solution is metabolically available to yeast cells to which it is added.