Previous corticosteroid exposure associates with an increased Pneumocystis jirovecii pneumonia mortality among HIV-negative patients: a global research network with a follow-up multicenter case-control study.

Background: HIV-negative patients have substantial mortality from Pneumocystis jirovecii pneumonia (PJP). We lack predictors of HIV-negative PJP-associated mortality. Objective: We aim to characterize the role of prior corticosteroid exposure in PJP-related mortality. Methods: We queried a global research network to identify adult HIV-negative patients with PJP with or without corticosteroid exposure in the preceding year before diagnosis (n = 8,021). We performed a propensity score-matched analysis to adjust baseline patient characteristics and analyzed outcomes. We follow-up the results with a multicenter ten years retrospective case-control cohort of HIV-negative patients tested for PJP by PCP Direct Fluorescent Antigen. We used a Cox proportional hazards model for survival analysis. Results: 1822 HIV-negative propensity-scored matched patients with prior corticosteroid exposure had significantly increased 10 weeks (16% versus 9%, p < 0.0001) and one-year mortality after PJP diagnosis (23% versus 14%, p < 0.0001). (1→3)-ß-D-glucan (197.6 ± 155.8 versus 63 ± 0 pg/ml, p = 0.014), ferritin levels (1227 ± 2486 versus 768 ± 1060 mcg/l, p = 0.047), lymphopenia (1.5 ± 1.5 versus 2.0 ± 1.6 103 cells/µl, p < 0.0001) and hypoxia (SatO2: 86.7% versus 91.6%, p < 0.0001) were higher or worse in those with prior steroid use. Patients who died were more likely to have previously received dexamethasone (35% versus 16%, p < 0.001) or prednisone (49% versus 29%, p < 0.001). Adjusted Cox proportional-hazard model validation showed an independently increased mortality at 10 weeks (HR: 3.7, CI: 1.5-9.2, p = 0.004) and 1 year (HR: 4.5, CI: 2.0-10.4, p < 0.0001) among HIV-negative patients with previous corticosteroid exposure. Conclusion: Preceding corticosteroids in HIV-negative patients with PJP are associated with higher mortality. A higher fungal burden may influence corticosteroid-mediated mortality. Assessment of PJP prophylaxis must become a standard clinical best practice when instituting corticosteroid therapy courses.

Misinterpretation in microplastic detection in biological tissues: When 2D imaging is not enough.

The presence of microplastics in the food chain is a public concern worldwide, and its analysis is an analytical challenge. In our research, we apply Raman imaging to study the presence of 1 µm polystyrene microplastics in cryosections of Mytilus galloprovincialis due to its wide geographic distribution, widespread occurrence in the food web, and general high presence in the environment. Ingested microplastics are accumulated in the digestive tract, but a large number can also be rapidly eliminated. Some authors state that the translocation of microplastics to the epithelial cells is possible, increasing the risk of microplastics transmission along the food chain. However, as seen in our study, a surface imaging approach (2D) is probably not enough to confirm the internalization of particles and avoid misinterpretation. In fact, while some microplastic particles were detected in the epithelium by 2D Raman imaging, further 3D Raman imaging analysis demonstrated that those particles were dragged from the lumens to the epithelium during sample preparation due to the blade drag effect of the cryotome, and subsequently located on the surface of the analyzed cryosection, discarding the translocation to the epithelial cells. This effect can also happen when the samples are fortuitously contaminated during sample preparation. Several research articles that use similar analytical techniques have shown the presence of microplastics in different types of tissue. It is not our intention to put such results in doubt, but the present work points out the necessity of appropriate three-dimensional analytical methods including data interpretation and the need to go a step further than just surface imaging analysis.

Design and Development of a Bimodal Optical Instrument for Simultaneous Vibrational Spectroscopy Measurements.

Vibrational spectroscopy techniques are widely used in analytical chemistry, physics and biology. The most prominent techniques are Raman and Fourier-transform infrared spectroscopy (FTIR). Combining both techniques delivers complementary information of the test sample. We present the design, construction, and calibration of a novel bimodal spectroscopy system featuring both Raman and infrared measurements simultaneously on the same sample without mutual interference. The optomechanical design provides a modular flexible system for solid and liquid samples and different configurations for Raman. As a novel feature, the Raman module can be operated off-axis for optical sectioning. The calibrated system demonstrates high sensitivity, precision, and resolution for simultaneous operation of both techniques and shows excellent calibration curves with coefficients of determination greater than 0.96. We demonstrate the ability to simultaneously measure Raman and infrared spectra of complex biological material using bovine serum albumin. The performance competes with commercial systems; moreover, it presents the additional advantage of simultaneously operating Raman and infrared techniques. To the best of our knowledge, it is the first demonstration of a combined Raman-infrared system that can analyze the same sample volume and obtain optically sectioned Raman signals. Additionally, quantitative comparison of confocality of backscattering micro-Raman and off-axis Raman was performed for the first time.

Visceral leishmaniasis in the island of Margarita, Venezuela: a neglected parasitic infection in the Caribbean.

Visceral leishmaniasis carries a significant burden of disease in the Americas with up to 7000 cases reported annually. There are several reports of autochthonous visceral leishmaniasis cases in the Caribbean, including the Dominican Republic, Guadalupe, Martinique, and Trinidad and Tobago. However, we lack recent clinical description and epidemiologic data of visceral leishmaniasis in other islands in the Caribbean. Herein, we describe an autochthonous case of visceral leishmaniasis in the Caribbean Island of Margarita in Venezuela. This index case of visceral leishmaniasis highlights the need for further regional surveillance efforts to identify animal reservoirs and to monitor the occurrence of further clinical cases. Additionally, there is an urgent need for implementing vector control strategies.

Experiences with Diagnosis and Treatment of Chagas Disease at a United States Teaching Hospital-Clinical Features of Patients with Positive Screening Serologic Testing.

Chagas disease (CD) is the third most common parasitic infection globally and can cause cardiac and gastrointestinal complications. Around 300,000 carriers of CD live in the U.S., with about 3000 of those in Colorado. We described our experience in diagnosing CD at a Colorado teaching hospital to revise screening eligibility criteria. From 2006 to 2020, we reviewed Trypanosoma cruzi (TC) IgG serology results for 1156 patients in our institution. We identified 23 patients (1.99%) who had a positive test. A total of 14/23 (60%) of positive serologies never had confirmatory testing, and 7 of them were lost to follow up. Confirmatory testing, performed in 9 patients, resulted in being positive in 3. One additional case of CD was identified by positive tissue pathology. All four confirmed cases were among patients born in Latin America. While most of the testing for CD at our institution is part of the pretransplant screening, no confirmed cases of CD derived from this strategy. Exposure risk in this population is not always documented, and initial positive results from screening are not always confirmed. The lack of standardized screening protocols for CD in our institution contributes to underdiagnosis locally and in health systems nationwide. Given a large number of individuals in the U.S. with chronic CD, improved screening is warranted.

Systems involved in K+ uptake from diluted solutions in pepper plants as revealed by the use of specific inhibitors.

Here, the contribution of the HAK1 transporter, the AKT1 channel and a putative AtCHX13 homolog to K(+) uptake in the high-affinity range of concentrations in pepper plants was examined. The limited development of molecular tools in pepper plants precluded a reverse genetics study in this species. By contrast, in the model plant Arabidopsis thaliana, these type of studies have shown that NH(4)(+) and Ba(2+) may be used as specific inhibitors of the two K(+) uptake systems to dissect their contribution in species in which, as in pepper, specific mutant lines are not available. By using these inhibitors together with Na(+) and Cs(+), the relative contributions of CaHAK1, CaAKT1 and a putative AtCHX13 homolog to K(+) acquisition from diluted solutions under different regimens of K(+) supply were studied. The results showed that, in plants completely starved of K(+), the gene encoding CaHAK1 was highly expressed and this system is a major contributor to K(+) uptake. However, K(+) concentrations as low as 50µM reduced CaHAK1 expression and the CaAKT1 channel came into play, participating together with CaHAK1 in K(+) absorption. The contribution of a putative AtCHX13 homolog seemed to be low under this low K(+) supply, but it cannot be ruled out that at higher K(+) concentrations this system participates in K(+) uptake. Studies of this type allow extension of the tools developed in model plants to understand nutrition in important crops.

Exposure assessment of polybrominated diphenyl ethers (PBDEs) in Mexican children.

Flame retardants (FRs) constitute a group of compounds that are added to materials in order to suppress, reduce, or delay fire. At present the most used FRs are the polybrominated diphenyl ethers (PBDEs), and diverse studies have found individuals exposed to them. However, few studies have reported data in children. The objective of this report was to assess PBDEs levels in children of six communities in México. During the year 2006 we analyzed a total of 173 healthy children (aged 6-13 years old). Plasma samples were taken and quantified (gas chromatography/mass spectrometer) for PBDEs. Six PBDEs congeners (BDE-47, BDE-99, BDE-100, BDE-153, BDE-154, and BDE-209) were quantified in blood serum. We detected exposure to PBDEs in all the communities. The total PBDEs levels ranged from no detectable (nd) to 43.4 ng g(-1) lipid, the dominant PBDE congener was BDE-47, followed by BDE-100, BDE-99 and BDE-153, whereas the levels of BDE-209 were below LOD. Children living in an industrial and urban area (Cd. Juarez, Chih) had the highest levels of PBDEs, approximately two times that of children living in El Refugio, S.L.P. (a rural area) or in Milpillas, S.L.P. (municipal landfill) and 4-5 times higher than levels found in children living in San Luis Potosi, S.L.P. (urban area), in Chihuahua, Chih. (urban area), and San Juan Tilapa, Edo. Mex. (municipal landfills). Results cannot be generalized since the communities selected are not representative of the Mexican population. However, they do indicate that Mexican children are exposed to PBDEs.