Thermal Stability of (Bio)Carbonates: A Potential Signature for Detecting Life on Mars?

The environmental conditions that prevail on the surface of Mars (i.e., high levels of radiation and oxidants) are not favorable for the long-term preservation of organic compounds on which all strategies for finding life on Mars have been based to date. Since life commonly produces minerals that are considered more resilient, the search for biominerals could constitute a promising alternative approach. Carbonates are major biominerals on Earth, and although they have not been detected in large amounts at the martian surface, recent observations show that they could constitute a significant part of the inorganic component in the martian soil. Previous studies have shown that calcite and aragonite produced by eukaryotes thermally decompose at temperatures 15°C lower than those of their abiotic counterparts. By using carbonate concretions formed by microorganisms, we find that natural and experimental carbonates produced by prokaryotes decompose at 28°C below their abiotic counterparts. The study of this sample set serves as a proof of concept for the differential thermal analysis approach to distinguish abiotic from bio-related carbonates. This difference in carbonate decomposition temperature can be used as a first physical evidence of life on Mars to be searched by in situ space exploration missions with the resolution and the technical constraints of the available onboard instruments.

Knowledge, attitudes, and practices regarding coccidioidomycosis among healthcare providers in four counties in Washington State, 2017

Coccidioidomycosis is an emerging infection in Washington State. The epidemiology of the disease in Washington is poorly understood at present; underrecognition and underreporting of coccidioidomycosis is suspected based on reports of only severe disease. We sought to characterize healthcare provider knowledge, attitudes, and practices regarding coccidioidomycosis awareness, diagnosis, and treatment in south-central Washington. We conducted a cross-sectional survey of actively practicing healthcare providers in four counties in south-central Washington, an area recently described as endemic for Coccidioides. Survey results were used to assess awareness of reporting requirements, confidence in ability to diagnose and treat, confidence that knowledge is current, calculated knowledge score, and consideration of risk in patient population. The majority of respondents were unaware of the reporting requirement for coccidioidomycosis in Washington and further unaware that the disease had been reported in the state. Less than a third of survey respondents reported confidence in their ability to diagnose coccidioidomycosis and confidence that their knowledge is current. The majority of respondents never or rarely consider a diagnosis of coccidioidomycosis, and <25% of respondents indicated a working knowledge of serologic tests for the infection. The average knowledge score for respondents was 65%. Previous education, training, or practice regarding coccidioidomycosis was the only identified predictor of confidence and consideration of risk. These data indicate the substantial need for education and training among healthcare providers in south-central Washington and support the concern that a small proportion of existing cases of coccidioidomycosis are reported to the health department.

Outcomes of HIV-positive patients with cryptococcal meningitis in the Americas

BACKGROUND

Cryptococcal meningitis (CM) is associated with substantial mortality in HIV-infected patients. Optimal timing of antiretroviral therapy (ART) in persons with CM represents a clinical challenge, and the burden of CM in Latin America has not been well described. Studies suggest that early ART initiation is associated with higher mortality, but data from the Americas are scarce.

METHODS

HIV-infected adults in care between 1985-2014 at participating sites in the Latin America (the Caribbean, Central and South America network (CCASAnet)) and the Vanderbilt Comprehensive Care Clinic (VCCC) and who had CM were included. Survival probabilities were estimated. Risk of death when initiating ART within the first 2 weeks after CM diagnosis versus initiating between 2-8 weeks was assessed using dynamic marginal structural models adjusting for site, age, sex, year of CM, CD4 count, and route of HIV transmission.

FINDINGS

340 patients were included (Argentina 58, Brazil 138, Chile 28, Honduras 27, Mexico 34, VCCC 55) and 142 (42%) died during the observation period. Among 151 patients with CM prior to ART 56 (37%) patients died compared to 86 (45%) of 189 with CM after ART initiation (p=0.14). Patients diagnosed with CM after ART had a higher risk of death (p=0.03, log-rank test). The probability of survival was not statistically different between patients who started ART within 2 weeks of CM (7/24, 29%) vs. those initiating between 2-8 weeks (14/53, 26%) (p=0.96), potentially due to lack of power.

INTERPRETATION

In this large Latin-American cohort, patients with CM had very high mortality rates, especially those diagnosed after ART initiation. This study reflects the overwhelming burden of CM in HIV-infected patients in Latin America.

Trauma to the bladder and ureter: a review of diagnosis, management, and prognosis

BACKGROUND

Injuries to the ureter or bladder are relatively rare. Therefore, a high level of clinical suspicion and knowledge of operative anatomy is of utmost importance for their management. Herein, a review of the literature related to the modern diagnosis, management, and prognosis for bladder and ureteral injuries is presented.

METHODS

A literature search was conducted through PubMed. A thorough search of the world's literature published in English was completed. Search terms included "injury, diagnosis, prognosis, and management for ureter and bladder". All years, both genders, as well as penetrating, blunt, and iatrogenic mechanisms were evaluated for inclusion. Following PRISMA guidelines, studies were selected based on relevance and then categorized.

RESULTS

172 potentially relevant studies were identified. Given our focus on modern diagnosis and treatment, we then narrowed the studies in each category to those published within the last 30 years, resulting in a total of 26 studies largely consisting of Level IV retrospective case series. Our review found that bladder ruptures occur from penetrating, blunt, or iatrogenic mechanisms, and most are extraperitoneal (63%). Ureteral injuries are incurred from penetrating mechanisms in 77% of cases. The overall mortality rates for bladder rupture and ureteral injury were 8 and 7%, respectively.

LIMITATIONS

Limitations of this article are similar to all PRISMA-guided review articles: the dependence on previously published research and availability of references.

CONCLUSION

The bladder is injured far more often than the ureter but ureteral injuries have higher injury severity. Both of these organs can be damaged by penetrating, blunt, or iatrogenic mechanisms and surgical intervention is often required for severe ureter or bladder injuries. Since symptoms of these injuries may not always be apparent, a high level of suspicion is required for appropriate diagnosis and treatment.

MEP (Mars Environment Package): toward a package for studying environmental conditions at the surface of Mars from future lander/rover missions

In view to prepare Mars human exploration, it is necessary to promote and lead, at the international level, a highly interdisciplinary program, involving specialists of geochemistry, geophysics, atmospheric science, space weather, and biology. The goal of this program will be to elaborate concepts of individual instruments, then of integrated instrumental packages, able to collect exhaustive data sets of environmental parameters from future landers and rovers of Mars, and to favour the conditions of their implementation. Such a program is one of the most urgent need for preparing human exploration, in order to develop mitigation strategies aimed at ensuring the safety of human explorers, and minimizing risk for surface operations. A few main areas of investigation may be listed: particle and radiation environment, chemical composition of atmosphere, meteorology, chemical composition of dust, surface and subsurface material, water in the subsurface, physical properties of the soil, search for an hypothesized microbial activity, characterization of radio-electric properties of the Martian ionosphere. Scientists at the origin of the present paper, already involved at a high degree of responsibility in several Mars missions, and actively preparing in situ instrumentation for future landed platforms (Netlander--now cancelled, MSL-09), express their readiness to participate in both ESA/AURORA and NASA programs of Mars human exploration. They think that the formation of a Mars Environment working group at ESA, in the course of the AURORA definition phase, could act positively in favour of the program, by increasing its scientific cross-section and making it still more focused on human exploration.

Validation of multimedia models assessing exposure to PAHs--the SOLEX study

Polluted soils have become a public health problem. While population exposure to soil pollutants is generally quantified using multimedia models, their estimations have not been validated, and studies that attempted to do so are scarce. The objective of the SOLEX study was to compare the predictions of pyrene exposure levels (converted into 1 hydroxypyrene) computed by several models with the results of urinary 1-hydropyrene (1-HOP) assays among 110 employees working at three sites polluted during their past use as manufactured gas plants. Four models were used: AERIS (Canada), CalTOX (California, USA), CLEA (UK), and HESP (The Netherlands). Three occupational exposure scenarios--with office, mixed, and outdoor workers--were constructed, based upon job activities during two measurement campaigns, one in winter and one in summer. The exposure levels estimated by the four models could differ markedly (from 7 up to 80 times) according to the exposure scenario. Also, the predominant exposure routes differed according to the model (direct soil ingestion for HESP and CalTOX, inhalation for AERIS, and dermal absorption for CLEA). The predictions of CalTOX are consistent with the 1-HOP measurements for all the scenarios. For HESP, the consistency is observed for the scenarios, office and mixed, for which the pyrene level in the soil is low. AERIS and CLEA yield results that are systematically above the 1-HOP measurements. This study confirms that validation of the models is crucial and points out to the need to proceed to assess components of the models that are the most influential using appropriate statistical analysis in combination with true field data.

Personal exposure of workers to atmospheric PAHs on gasworks sites--The SOLEX study

The aim of the SOLEX study was to estimate the personal exposure of workers to atmospheric polycyclic aromatic hydrocarbons (PAHs) on former gasworks sites in the Paris metropolitan area. Devices to sample gas and particulate phases for 9 PAHs were carried during one working day of a study week in November 1997 by 24 workers and in June 1998 by 19 workers with contrasted job profiles involving different opportunities for contact with the soil; among these volunteers, some were active in the process of contaminated soil remediation during the November study period. PAH concentrations were measured by high-performance liquid chromatography. Subjects working on the site under remediation were clearly more exposed (684.1 ng/m3 for total PAHs in November 1997) than workers, without close contact with soil, whose PAH exposure was similar to that measured by fixed monitors in the ambient air in Paris. The contrasts were weaker in June 1998, when soil remediation had nearly been completed. Only subjects involved in activities with close contact with the ground were found with exposures exceeding background levels. Further investigations are needed to improve our understanding of the influence of the pollutants present in the soil.

EXOCAM: Mars in a box to simulate soil-atmosphere interactions

We present the principle of the EXOCAM chamber, devoted to the study of physical-chemical interactions between the atmosphere and the surface and subsurface in Mars conditions. The purpose of this experiment is to reach a better knowledge of the physical and chemical processes that altered the atmosphere-soil coupled system. We describe the scientific goals of EXOCAM, the multiple fields that will benefit from this experiment and the instrumentation that is devoted to the analysis of the results. We also give a description of the chamber and its main devices.

Feasibility of assessing dermal exposure to PAHs of workers on gaswork sites--the SOLEX study

Population exposure to pollutants in soil is an important public health concern. Difficult to measure, it is usually estimated using multimedia models. Modeling data predict that the skin surface is a predominant exposure route in roughly 15% of the US Superfund sites. Nonetheless, no study has confirmed these predictions. The SOLEX study was an opportunity to study the feasibility of estimating the cutaneous polycyclic aromatic hydrocarbons (PAHs: all 16 of the United States Environmental Protection Agency list) load of workers at three former manufactured gas sites, one of those being under remediation. Over two measurement periods (November 1997 and June 1998), 30 and 28 volunteers, respectively, were equipped for a single day work with five pads that collected soil particles and were placed at the neck, shoulder, wrist, groin, and ankle. Pad contamination was observed for six of the nine workers on the site being remediated but not on other sites. The wrist pad was most often affected, followed by the neck pad, these are, the exposed regions of the body. The PAHs most frequently identified were anthracene, fluoranthene, naphthalene, phenanthrene, and pyrene, at concentrations relatively high. In conclusion, this study showed that estimating skin exposure to soil pollutants is feasible. Secondly, it suggested that only subjects in close contact with the soil had a detectable exposure to PAHs. Extension of this approach to other exposure settings is warranted, especially among children playing in polluted public or private gardens, because their games lead to frequent contact with the soil.

Urinary 1-hydroxypyrene as a biomarker of polycyclic aromatic hydrocarbons exposure of workers on a contaminated site: influence of exposure conditions

The aim of the study was to determine the exposure levels of workers to polycyclic aromatic hydrocarbons on gasworks sites by the measurement of urinary 1-hydroxypyrene. Start-shift and end-shift urine samples were taken every day during an entire week (Monday to Friday), once in November and a second time in June. Four groups of workers were selected according to their activity. Increased exposure was only found among volunteers involved in the remediation of a site, 0.16 to 2.31 mumol/mol creatinine in non-smokers. The median of the non-smoker referent group was 0.02 mumol/mol creatinine (95% confidence interval, 0.01 to 0.04). Smokers had greater exposure levels than non-smokers in every group. Within and between variability was around 200%. Assessment of the exposure of persons on contaminated soil is possible, with the condition that the exposed subjects come in direct contact with the soil.

Side chain conjugation prevents bacterial 7-dehydroxylation of bile acids

The effect of side chain conjugation on 7-dehydroxylation of bile acids has been investigated. C24-bile acids and their glycine and taurine conjugates and keto bile acids were incubated with pure strains of Eubacterium sp. VPI 12708. Bile acids of the 5 alpha- or 5 beta-series with a free terminal carboxyl group and a 3 alpha, 7 alpha-dihydroxy system were very effectively 7 alpha-dehydroxylated, whereas 7 beta-hydroxy bile acids resisted 7-dehydroxylation. Oxo bile acids were metabolized at the oxygen function also. Glycine- and taurine-conjugated bile acids were neither deamidated nor 7-dehydroxylated by the bacteria. Thus, side chain conjugation prevents 7-dehydroxylation of bile acids by Eubacterium sp. VPI 12708.

Translation in micrococcal nuclease-treated cell-free extracts from Ehrlich ascites tumor cells. Stimulation by initiation factor eIF-2B

Translation of exogenous mRNAs in micrococcal nuclease-treated extracts from Ehrlich ascites tumor cells is greatly stimulated by the addition of crude initiation factors or initiation factors eIF-2B and eIF-2 containing eIF-2B. The requirement for exogenous eIF-2B in micrococcal nuclease-treated extracts does not result from either loss or enhanced phosphorylation of eIF-2 during incubation.

The translation of the messenger for the poly(A)-binding protein-associated with translated mRNA is suppressed. A case of cytoplasmic repression in duck erythroblasts

In vivo protein synthesis in duck erythroblasts was compared to in vitro translation of polyribosomal and free cytoplasmic mRNA. The in vivo study showed the absence of de novo synthesis of the Mr 73 000 poly(A)-binding protein found associated with all polyribosomal mRNA. In vitro translation demonstrated that the mRNA for this protein is absent from the polyribosomal mRNA fraction but constitutes a medium frequency messenger among the repressed free mRNA. This result confirms the existence of a qualitative translational control in terminal differentiating duck erythroblasts leading eventually to the arrest of the protein synthesizing machinery.

Solubilization of a protein synthesis inhibitor from vaccinia virions

The protein synthesis inhibitor previously demonstrated to be associated with vaccinia cores was quantitatively solubilized from vaccinia virions or cores after an endogenous protein kinase reaction at pH 10. The presence of the inhibitor in the soluble extract correlated with the presence of soluble virion proteins phosphorylated in vitro. Partially purified inhibitor blocked methionyl-tRNAfMet-40S initiation complex formation, as was the case in cell-free extracts derived from vaccinia virus-infected cells.

Studies on multi-antibiotic resistant strains of Staphylococcus aureus

Twenty-seven isolates of Staphylococcus aureus were found to be resistant to methicillin, nafcillin, tobramycin, gentamicin, amikacin, cefoxitin, clindamycin, erythromycin and chloramphenicol by disc diffusion testing and tube dilution studies; they were sensitive to cefamandole, cephalothin and vancomycin by disc testing. A discrepancy between minimum inhibitory and bactericidal concentrations was noted for the cephalosporins which was not appreciated on disc testing. All isolates were very sensitive to rifampin (minimum bactericidal concentration 0.3 mg/l). All isolates were susceptible to phage type 83A. A subpopulation of variant small-colony forms of Staphylococcus aureus was recovered when superinhibitory amounts of aminoglycosides and methicillin were used. The variant Staphylococcus aureus strains retained the same antibiotic susceptibility patterns and phage type as their parent strain of Staphylococcus aureus. Further studies are in progress concerning these isolates and their impact on the hospital flora at our institution.

Species identification of coagulase-negative staphylococcal isolates from blood cultures

Coagulase-negative staphylococci generally are not fully identified, are called Staphylococcus epidermidis, and are considered contaminants when isolated from blood cultures. In a cancer hospital during 6 months, 46 patients had multiple blood cultures (mean, 3.1) which yielded coagulase-negative staphylococci. Species identification of these showed that 10 of the 46 (22%) were not S. epidermidis. Similarly, 96 coagulase-negative staphylococci isolated from only one of multiple blood cultures from patients and thought to be skin contaminants were identified. Of 96 of the staphylococci, 14 (16%) of the latter group were not S. epidermidis. Species found included S. haemolyticus, S. hominis, S. warneri, S. simulans, and S. xylosus. Eight isolates of these species were methicillin resistant, and all eight were mannitol fermenters. The results suggest that these species invasively infect cancer patients with the same frequency at which the species colonize. No one species was identified as being more pathogenic than the others. Routine species identification of coagulase-negative staphylococci from blood cultures of cancer patients contributed little to management except to occasionally distinguish multiple-episode culture contamination by different species from sustained bacteremia with the same species.

Serum cryptococcal antigen determination in the presence of rheumatoid factor

Sera from nine patients with cryptococcal infections and from four with rheumatoid arthritis and positive rheumatoid factor were examined for the presence of cryptococcal capsular antigen by the latex agglutination method. Ethylenediaminetetraacetic acid-heat treatment of the sera before testing possibly increased sensitivity as compared with the untreated sera, and the interfering rheumatoid factor activity was eliminated.

Susceptibility of zygomycetes to amphotericin B, miconazole, and ketoconazole

Susceptibility to amphotericin B, miconazole, and ketoconazole was determined for 25 clinical isolates of zygomycetes in yeast nitrogen base broth and human serum. In yeast nitrogen base broth, 7 of 25 isolates were susceptible to an imidazole or amphotericin B. In serum, all were resistant to the imidazoles and inhibited by amphotericin B, the current drug of choice for infections caused by zygomycetes.

Inhibition of 40S--Met--tRNAfMet ribosomal initiation complex formation by vaccinia virus

Infection with vaccinia virus (a poxvirus) quickly and efficiently shuts off host protein synthesis in the presence of actinomycin D (refs 3--5) or cycloheximide. The cellular messenger RNA apparently remains stable in the infected cells exposed to inhibitors of viral gene transcription. In some cases vaccinia viral RNA or poly(A) synthesis have been implicated in the establishment of this effect. However, in the presence of cordycepin (3-deoxyadenosine) which blocks viral gene transcription and cytoplasmic poly(A) synthesis, cellular protein synthesis is still efficiently inhibited in vaccinia virus-infected cells. This shutoff is also observed in vitro, in the corresponding cell-free extracts, and in a reticulocyte lysate. Therefore the shutoff of host protein synthesis is probably mediated by a factor associated with vaccinia virions. We now report that the formation of the 40S--Met-tRNAfMet initiation complex is inhibited in cytoplasmic extracts derived from vaccinia virus-infected cells exposed to cordycepin to block viral gene expression. A similar inhibition is found in reticulocyte lysates incubated with purified vaccinia cores, confirming the hypothesis that the factor associated with the viral cores is responsible for the inhibition observed in vaccinia virus-infected cells exposed to inhibitors of transcription.

Inhibition of host protein synthesis in vaccinia virus-infected cells in the presence of cordycepin (3'-deoxyadenosine)

Cordycepin inhibited efficiently viral mRNA and polyadenylic acid syntheses in vaccinia virus-infected cells, but allowed the shutoff of host protein synthesis to occur. Therefore, cordycepin was used to study this shutoff in the absence of gene expression. Ribosome transit time was increased in infected cells, revealing an inhibition at the level of elongation and/or release of polypeptide chains. However, the disappearance of heavy polysomes in vaccinia virus-infected cells showed that the inhibition of host protein synthesis resulted predominantly from a block at the stage of initiation. This conclusion was confirmed by the recovery of heavy polyribosomes when low levels of cycloheximide were added to slow down ribosome release from the mRNA. Similar amounts of cellular mRNA (present in the polyribosomes) were found in vaccinia virus-infected cells and in mock-infected cels (exposed to cordycepin), showing that the cellular mRNA was not inactivated in these conditions. It was concluded that a component of the vaccinia virion inhibits, in the absence of viral RNA and polyadenylic acid syntheses, host protein synthesis at the level of initiation and, to a lesser extent, at the level of elongation (and/or release) of polypeptide chains.