Survival and recovery modeling of acute kidney injury in critically ill adults

Objectives: Acute kidney injury is common among the critically ill. However, the incidence, medication use, and outcomes of acute kidney injury have been variably described. We conducted a single-center, retrospective cohort study to examine the risk factors and correlates associated with acute kidney injury in critically ill adults with a particular focus on medication class usage. Methods: We reviewed the electronic medical records of all adult patients admitted to an intensive care unit between 1 February and 30 August 2020. Acute kidney injury was defined by the 2012 Kidney Disease: Improving Global Outcomes guidelines. Data included were demographics, comorbidities, symptoms, laboratory parameters, interventions, and outcomes. The primary outcome was acute kidney injury incidence. A Least Absolute Shrinkage and Selection Operator regression model was used to determine risk factors associated with acute kidney injury. Secondary outcomes including acute kidney injury recovery and intensive care unit mortality were analyzed using a Cox regression model. Results: Among 226 admitted patients, 108 (47.8%) experienced acute kidney injury. 37 (34.3%), 39 (36.1%), and 32 patients (29.6%) were classified as acute kidney injury stages I–III, respectively. Among the recovery and mortality cohorts, analgesics/sedatives, anti-infectives, and intravenous fluids were significant (p-value \u3c 0.05). The medication classes IV-fluid electrolytes nutrition (96.7%), gastrointestinal (90.2%), and anti-infectives (81.5%) were associated with an increased odds of developing acute kidney injury, odd ratios: 1.27, 1.71, and 1.70, respectively. Cox regression analyses revealed a significantly increased time-varying mortality risk for acute kidney injury-stage III, hazard ratio: 4.72 (95% confidence interval: 1–22.33). In the recovery cohort, time to acute kidney injury recovery was significantly faster in stage I, hazard ratio: 9.14 (95% confidence interval: 2.14–39.06) cohort when compared to the stage III cohort. Conclusion: Evaluation of vital signs, laboratory, and medication use data may be useful to determine acute kidney injury risk stratification. The influence of particular medication classes further impacts the risk of developing acute kidney injury, necessitating the importance of examining pharmacotherapeutic regimens for early recognition of renal impairment and prevention

Purine nucleoside phosphorylase: A new marker for free oxygen radical injury to the endothelial cell

The effect of ischemia and reperfusion on purine nucleoside phosphorylase was studied in an isolated perfused rat liver model. This enzyme is localized primarily in the cytoplasm of the endothelial and Kupffer cells; some activity is associated with the parenchymal cells. Levels of this enzyme accurately predicted the extent of ischemia and reperfusion damage to the microvascular endothelial cell of the liver. Livers from Lewis rats were subjected to 30, 45 and 60 min of warm (37° C) no flow ischemia that was followed by a standard reperfusion period lasting 45 min. Purine nucleoside phosphorylase was measured at the end of the no flow ischemia and reperfusion periods as was superoxide generation (O2‐). Bile production was monitored throughout the no flow ischemia and reperfusion periods. Control perfusions were carried out for 120 min. A significant rise in purine nucleoside phosphorylase levels as compared with controls was observed at the end of ischemia in all the three groups. The highest level, 203.5 ± 29.2 mU/ml, was observed after 60 min of ischemia. After the reperfusion period, levels of purine nucleoside phosphorylase decreased in the 30‐ and 45‐min groups 58.17 ± 9.66 mU/ml and 67.5 ± 17.1 mU/ml, respectively. These levels were equal to control perfusions. In contrast, after 60 min of ischemia, levels of purine nucleoside phosphorylase decreased early in the reperfusion period and then rose to 127.8 ± 14.8 mU/ml by the end of reperfusion (p < 0.0001). Superoxide generation at the beginning of reperfusion was higher than in controls with similar values observed at the end of 30, 45 and 60 min of ischemia. During reperfusion, production of superoxide continued. Bile production was significantly lower at the end of 30 min (0.044 ± 0.026 μl/min/gm), 45 min (0.029 ± 0.0022 μ/min/gm) and 60 min of ischemia (0.022 ± 0.008 μ/min/gm) when compared with bile production by control livers during the corresponding time (0.680 ± 0.195, 0.562 ± 0.133 and 0.480 ± 0.100 μ/min/gm respectively; p < 0.001). During reperfusion, rates of bile production were normal after 30 and 45 min of ischemia. In contrast, significantly lower rates of bile production, 0.046 ± 0.36 μ/min/gm (p < 0.001) occurred during reperfusion after 60 min of ischemia. Control livers during the same period produced 0.330 ± 0.056 μl/min/gm of bile. The results indicate that purine nucleoside phosphorylase levels may be a good index of oxidative injury to the liver in ischemia reperfusion and reliably predict the functional state of the organ after reperfusion. Copyright © 1990 American Association for the Study of Liver Disease

COVID-19 cases and testing in 53 prison systems

Background: COVID-19 has entered United States prison systems at alarming rates. Disparities in social and structural determinants of health disproportionately affect those experiencing incarceration, making them more vulnerable to COVID-19. Additionally, prisons are sites of congregate living, making it impossible to practice social distancing, and most prisons have relied only on incremental measures to reduce risk and spread of COVID-19. To more fully understand the impact that COVID-19 is having on incarcerated populations, it is critical to have systematic data on testing, test positivity, cases, and case fatality. Using data from the COVID Prison Project, we present data on 53 prison systems COVID-19 testing, test positivity, case, and case fatality by state and compare these data with each state’s general population. We do this for the early stages of the pandemic, utilizing data through July 15, 2020. Results: Many states are not reporting full information on COVID testing with some also not reporting on case fatality. Among those reporting data, there is a wide variation between testing, test positivity, and case rates within prison systems and as compared to the general population. However, when more tests are deployed more cases are identified with the majority of state prisons having higher case rates than their general population. Conclusions: These findings underscore the need for the implementation and study of COVID-19 mitigation and surveillance strategies to flatten the COVID-19 curve in prisons across the country. We call for future research to build on these data from the COVID Prison Project to protect the health of our nations’ often forgotten residents

Multiparameter digitized video microscopy of toxic and hypoxic injury in single cells.

There is no clear picture of the critical events that lead to the transition from reversible to irreversible injury. Many studies have suggested that a rise in cytosolic free Ca2+ initiates plasma membrane bleb formation and a sequence of events that lead ultimately to cell death. In recent studies, we have measured changes in cytosolic free Ca2+, mitochondrial membrane potential, cytosolic pH, and cell surface blebbing in relation to the onset of irreversible injury and cell death following anoxic and toxic injury to single hepatocytes by using multiparameter digitized video microscopy (MDVM). MDVM is an emerging new technology that permits single living cells to be labeled with multiple probes whose fluorescence is responsive to specific cellular parameters of interest. Fluorescence images specific for each probe are collected over time, digitized, and stored. Image analysis and processing then permits quantitation of the spatial distribution of the various parameters with the single living cells. Our results indicate the following: The formation of plasma membrane blebs accompanies all types of injury in hepatocytes. Cell death is a rapid event initiated by rupture of a plasma membrane bleb, and it is coincident with the onset of irreversible injury. An increase of cytosolic free Ca2+ is not the stimulus for bleb formation or the final common pathway leading to cell death. A decrease of mitochondrial membrane potential precedes the loss of cell viability. Cytosolic pH falls by more than 1 pH unit during chemical hypoxia. This acidosis protects against the onset of cell death

Evidence of reproductive endocrine effects in women with occupational fuel and solvent exposures.

Hydrocarbons (HCs) found in fuels and solvents are ubiquitous in the environment, yet we know little about their effects on the endocrine system. The objective of this study was to assess the potential reproductive endocrine effects of low-dose HCs encountered by female U.S. Air Force personnel with fuel (primarily JP-8 jet fuel) and solvent exposures (n = 63). We estimated the internal dose of HCs in fuels and solvents by measuring their levels in exhaled breath, including the sum of aliphatic HCs (C6H14-C16H34) and the sum of aromatic HCs (benzene, ethylbenzene, toluene, and m,p,o-xylenes). Adverse outcome measures included urinary endocrine markers that have been associated with nonconceptive (vs. conceptive) menstrual cycles in ovulatory women: lower preovulatory luteinizing hormone (LH) and mid-luteal phase pregnanediol 3-glucuronide (Pd3G) and estrone 3-glucuronide, and higher follicle phase Pd3G. We also obtained reproductive and exposure information from baseline questionnaires and daily diaries. Toluene was the most frequently found analyte in the breath, with values up to 52.0 ppb, and benzene breath levels were up to 97.5 ppb. Regression analysis revealed that preovulatory LH levels were significantly lower (p = 0.007) among women whose total aliphatic HC levels were above the median. The relationship between elevated aliphatic HC exposure and lowered preovulatory LH levels in the present study suggests that compounds in fuels and some solvents may act as reproductive endocrine disruptors. Confirmation of these findings is needed, not only to determine if fuel and solvent exposure may impact other LH-dependent physiologic functions but also to examine effects of fuels and solvents on conception

Brillouin Light Scattering of Spin Waves Inaccessible with Free-Space Light

Micro-focus Brillouin light scattering is a powerful technique for the spectroscopic and spatial characterization of elementary excitations in materials. However, the small momentum of light limits the accessible excitations to the center of the Brillouin zone. Here, we utilize a metallic nanoantenna fabricated on the archetypal ferrimagnet yttrium iron garnet to demonstrate the possibility of Brillouin light scattering from large-wavevector, high-frequency spin wave excitations that are inaccessible with free-space light. The antenna facilitates sub-diffraction confinement of electromagnetic field, which enhances the local field intensity and generates momentum components significantly larger than those of free-space light. Our approach provides access to high frequency spin waves important for fast nanomagnetic devices, and can be generalized to other types of excitations and light scattering techniques.Comment: 6 pages, 4 figure

Intracellular pH during "chemical hypoxia" in cultured rat hepatocytes. Protection by intracellular acidosis against the onset of cell death.

L'acidose intracellulaire protège de la mort hépato-cellulaire par déplétion d'ATP, un phénomène qui peut représenter une adaptation protectrice contre le stress hypoxique et ischémique

The mitochondrial permeability transition in cell death: a common mechanism in necrosis, apoptosis and autophagy

AbstractUsing confocal microscopy, onset of the mitochondrial permeability transition (MPT) in individual mitochondria within living cells can be visualized by the redistribution of the cytosolic fluorophore, calcein, into mitochondria. Simultaneously, mitochondria release membrane potential-indicating fluorophores like tetramethylrhodamine methylester. The MPT occurs in several forms of necrotic cell death, including oxidative stress, pH-dependent ischemia/reperfusion injury and Ca2+ ionophore toxicity. Cyclosporin A (CsA) and trifluoperazine block the MPT in these models and prevent cell killing, showing that the MPT is a causative factor in necrotic cell death. During oxidative injury induced by t-butylhydroperoxide, onset of the MPT is preceded by pyridine nucleotide oxidation, mitochondrial generation of reactive oxygen species, and an increase of mitochondrial free Ca2+, all changes that promote the MPT. During tissue ischemia, acidosis develops. Because of acidotic pH, anoxic cell death is substantially delayed. However, when pH is restored to normal after reperfusion (reoxygenation at pH 7.4), cell death occurs rapidly (pH paradox). This killing is caused by pH-dependent onset of the MPT, which is blocked by reperfusion at acidotic pH or with CsA. In isolated mitochondria, toxicants causing Reye’s syndrome, such as salicylate and valproate, induce the MPT. Similarly, salicylate induces a CsA-sensitive MPT and killing of cultured hepatocytes. These in vitro findings suggest that the MPT is the pathophysiological mechanism underlying Reye’s syndrome in vivo. Kroemer and coworkers proposed that the MPT is a critical event in the progression of apoptotic cell death. Using confocal microscopy, the MPT can be directly documented during tumor necrosis factor-α induced apoptosis in hepatocytes. CsA blocks this MPT and prevents apoptosis. The MPT does not occur uniformly during apoptosis. Initially, a small proportion of mitochondria undergo the MPT, which increases to nearly 100% over 1–3 h. A technique based on fluorescence resonance energy transfer can selectively reveal mitochondrial depolarization. After nutrient deprivation, a small fraction of mitochondria spontaneously depolarize and enter an acidic lysosomal compartment, suggesting that the MPT precedes the normal process of mitochondrial autophagy. A model is proposed in which onset of the MPT to increasing numbers of mitochondria within a cell leads progressively to autophagy, apoptosis and necrotic cell death

Basal reactive oxygen species determine the susceptibility to apoptosis in cirrhotic hepatocytes

Hepatocytes from cirrhotic murine livers exhibit increased basal ROS activity and resistance to TGFβ-induced apoptosis, yet when ROS levels are decreased by antioxidant pretreatment, these cells recover susceptibility to apoptotic stimuli. To further study these redox events, hepatocytes from cirrhotic murine livers were pretreated with various antioxidants prior to TGFβ treatment and the ROS activity, apoptotic response, and mitochondrial ROS generation were assessed. In addition, normal hepatocytes were treated with low-dose H2O2 and ROS and apoptotic responses determined. Treatment of cirrhotic hepatocytes with various antioxidants decreased basal ROS and rendered them susceptible to apoptosis. Examination of normal hepatocytes by confocal microscopy demonstrated co-localization of ROS activity and respiring mitochondria. Basal assessment of cirrhotic hepatocytes showed non-focal ROS activity that was abolished by antioxidants. After pretreatment with an adenovirus expressing MnSOD, basal cirrhotic hepatocyte ROS was decreased and TGFβ-induced co-localization of ROS and mitochondrial respiration was present. Treatment of normal hepatocytes with H2O2 resulted in a sustained increase in ROS and resistance to TGFβ apoptosis that was reversed when these cells were pretreated with an antioxidant. In conclusion, cirrhotic hepatocytes have a non-focal distribution of ROS. However, normal and cirrhotic hepatocytes exhibit mitochondrial localization of ROS that is necessary for apoptosis

Adverse childhood experiences and implications of perceived stress, anxiety and cortisol among women in Pakistan: a cross-sectional study

OBJECTIVES: Adverse childhood experiences (ACEs) are linked to poor maternal mental health. The goal of this study is to examine the associations between ACEs and multiple manifestations of stress (including perceived stress, anxiety and cortisol) among mothers in rural Pakistan. DESIGN: This study used a cross-sectional design. Mothers were originally recruited during their third trimester of pregnancy and followed until 36 months post partum. Cortisol was collected at 12 months post partum, and self-report data were collected at 36 months post partum. SETTING: All participants reside in rural villages in Rawalpindi, Pakistan. The measures were administered at home visits by field interviewers. PARTICIPANTS: Data were collected from 889 mothers. All mothers in the sample provided data on ACEs and perceived stress, 623 provided data on anxiety and 90 provided hair cortisol. PRIMARY AND SECONDARY OUTCOMES MEASURES: ACEs were captured retrospectively using an adapted version of the ACE International Questionnaire, and represented as a continuous variable and subdomains (neglect, home violence, family psychological distress, community violence). Primary outcomes included perceived stress measured with the Cohen Perceived Stress Scale (PSS) and anxiety measured with the Generalised Anxiety Disorder-7 scale (GAD-7). Hair-derived cortisol was included as a secondary outcome. Generalised linear models with cluster-robust SEs were used to estimate associations between ACEs and the outcome variables. RESULTS: All models featured positive associations between ACE items and PSS. The continuous total ACE score (B=0.4; 95% CI 0.0 to 0.8) was associated with higher anxiety symptoms on the GAD-7. Home violence (B=6.7; 95% CI 2.7 to 10.8) and community violence (B=7.5; 95% CI 1.4 to 13.6) were associated with increased hair cortisol production. CONCLUSIONS: All four ACE domains were associated with elevated levels of perceived stress, anxiety and cortisol, with varying precision and strength of estimates, indicating that the type of ACE has a differential impact. This study informed our understanding of the differential impact of specific ACEs on perceived stress, anxiety and hypothalamic pituitary adrenal-axis functioning, providing implications for future clinical intervention and research development