The thin red line: Blood planning factors and the enduring need for a robust military blood system to support combat operations.

ABSTRACT: Battlefield lessons learned are forgotten; the current name for this is the Walker Dip. Blood transfusion and the need for a Department of Defense Blood Program are lessons that have cycled through being learned during wartime, forgotten, and then relearned during the next war. The military will always need a blood program to support combat and contingency operations. Also, blood supply to the battlefield has planning factors that have been consistent over a century. In 2024, it is imperative that we codify these lessons learned. The linchpins of modern combat casualty care are optimal prehospital care, early whole blood transfusion, and forward surgical care. This current opinion comprised of authors from all three military Services, the Joint Trauma System, the Armed Services Blood Program, blood SMEs and the CCC Research Program discuss two vital necessities for a successful military trauma system: (1) the need for an Armed Services Blood Program and (2) Planning factors for current and future deployed military ere is no effective care for wounded soldiers, and by extension there is no effective military medicine.

A safety and feasibility analysis on the use of cold-stored platelets in combat trauma.

BACKGROUND: Damage-control resuscitation has come full circle, with the use of whole blood and balanced components. Lack of platelet availability may limit effective damage-control resuscitation. Platelets are typically stored and transfused at room temperature and have a short shelf-life, while cold-stored platelets (CSPs) have the advantage of a longer shelf-life. The US military introduced CSPs into the battlefield surgical environment in 2016. This study is a safety analysis for the use of CSPs in battlefield trauma. METHODS: The Department of Defense Trauma Registry and Armed Services Blood Program databases were queried to identify casualties who received room-temperature-stored platelets (RSPs) or both RSPs and CSPs between January 1, 2016, and February 29, 2020. Characteristics of recipients of RSPs and RSPs-CSPs were compared and analyzed. RESULTS: A total of 274 patients were identified; 131 (47.8%) received RSPs and 143 (52.2%) received RSPs-CSPs. The casualties were mostly male (97.1%), similar in age (31.7 years), with a median Injury Severity Score of 22. There was no difference in survival for recipients of RSPs (88.5%) versus RSPs-CSPs (86.7%; p = 0.645). Adverse events were similar between the two cohorts. Blood products received were higher in the RSPs-CSPs cohort compared with the RSPs cohort. The RSPs-CSPs cohort had more massive transfusion (53.5% vs. 33.5%, p = 0.001). A logistic regression model demonstrated that use of RSPs-CSPs was not associated with mortality, with an adjusted odds ratio of 0.96 (p > 0.9; 95% confidence interval, 0.41-2.25). CONCLUSION: In this safety analysis of RSPs-CSPs compared with RSPs in a combat setting, survival was similar between the two groups. Given the safety and logistical feasibility, the results support continued use of CSPs in military environments and further research into how to optimize resuscitation strategies. LEVEL OF EVIDENCE: Therapeutic/Care Management; Level IV.

A 20-year retrospective analysis of deep venous thrombosis and pulmonary embolism among combat casualties requiring damage-control laparotomy at US military Role 2 surgical units.

BACKGROUND: Combat casualties receiving damage-control laparotomy at forward deployed, resource-constrained US military Role 2 (R2) surgical units require multiple evacuations, but the added risk of venous thromboembolism (VTE) in this population has not been defined. To fill this gap, we retrospectively analyzed 20 years of Department of Defense Trauma Registry data to define the VTE rate in this population. METHODS: Department of Defense Trauma Registry from 2002 to 2023 was queried for US military combat casualties requiring damage-control laparotomy at R2. All deaths were excluded in subsequent analysis. Rates of VTE were assessed, and subgroup analysis was performed on patients requiring massive transfusion. RESULTS: Department of Defense Trauma Registry (n = 288) patients were young (mean age, 25 years) and predominantly male (98%) with severe (mean Injury Severity Score, 26), mostly penetrating injury (76%) and high mortality. Venous thromboembolism rate was high: 15.8% (DVT, 10.3%; pulmonary embolism, 7.1%). In the massively transfused population, the VTE rate was even higher (26.7% vs. 10.2%, p < 0.001). CONCLUSION: This is the first report that combat casualties requiring damage-control laparotomy at R2 have such high VTE rates. Therefore, for military casualties, we propose screening ultrasound upon arrival to each subsequent capable echelon of care and low threshold for initiating thromboprophylaxis. LEVEL OF EVIDENCE: Prognostic and Epidemiological; Level IV.

Higher Initial Formula for Resuscitation After Severe Burn Injury Means Higher 24-Hour Volumes.

Initial fluid infusion rates for resuscitation of burn injuries typically use formulas based on patient weight and total body surface area (TBSA) burned. However, the impact of this rate on overall resuscitation volumes and outcomes have not been extensively studied. The purpose of this study was to determine the impact of initial fluid rates on 24-hour volumes and outcomes using the Burn Navigator (BN). The BN database is composed of 300 patients with ≥20% TBSA, >40 kg that were resuscitated utilizing the BN. Four study arms were analyzed based on the initial formula-2 ml/kg/TBSA, 3 ml/kg/TBSA, 4 ml/kg/TBSA or the Rule of Ten. Total fluids infused at 24 hours after admission were compared as well as resuscitation-related outcomes. A total of 296 patients were eligible for analysis. Higher starting rates (4 ml/kg/TBSA) resulted in significantly higher volumes at 24 hours (5.2 ± 2.2 ml/kg/TBSA) than lower rates (2 ml/kg/TBSA resulted in 3.9 ± 1.4 ml/kg/TBSA). No shock was observed in the high resuscitation cohort, whereas the lowest starting rate exhibited a 12% incidence, lower than both the Rule of Ten and 3 ml/kg/TBSA arms. There was no difference in 7-day mortality across groups. Higher initial fluid rates resulted in higher 24-hour fluid volumes. The choice of 2ml/kg/TBSA as initial rate did not result in increased mortality or more complications. An initial rate of 2ml/kg/TBSA is a safe strategy.

APPRAISE-HRI: AN ARTIFICIAL INTELLIGENCE ALGORITHM FOR TRIAGE OF HEMORRHAGE CASUALTIES.

ABSTRACT: Background: Hemorrhage remains the leading cause of death on the battlefield. This study aims to assess the ability of an artificial intelligence triage algorithm to automatically analyze vital-sign data and stratify hemorrhage risk in trauma patients. Methods: Here, we developed the APPRAISE-Hemorrhage Risk Index (HRI) algorithm, which uses three routinely measured vital signs (heart rate and diastolic and systolic blood pressures) to identify trauma patients at greatest risk of hemorrhage. The algorithm preprocesses the vital signs to discard unreliable data, analyzes reliable data using an artificial intelligence-based linear regression model, and stratifies hemorrhage risk into low (HRI:I), average (HRI:II), and high (HRI:III). Results: To train and test the algorithm, we used 540 h of continuous vital-sign data collected from 1,659 trauma patients in prehospital and hospital (i.e., emergency department) settings. We defined hemorrhage cases (n = 198) as those patients who received ≥1 unit of packed red blood cells within 24 h of hospital admission and had documented hemorrhagic injuries. The APPRAISE-HRI stratification yielded a hemorrhage likelihood ratio (95% confidence interval) of 0.28 (0.13-0.43) for HRI:I, 1.00 (0.85-1.15) for HRI:II, and 5.75 (3.57-7.93) for HRI:III, suggesting that patients categorized in the low-risk (high-risk) category were at least 3-fold less (more) likely to have hemorrhage than those in the average trauma population. We obtained similar results in a cross-validation analysis. Conclusions: The APPRAISE-HRI algorithm provides a new capability to evaluate routine vital signs and alert medics to specific casualties who have the highest risk of hemorrhage, to optimize decision-making for triage, treatment, and evacuation.

The Battle of the Titans-Comparing Resuscitation Between Five Major Burn Centers Using the Burn Navigator.

The goal of burn resuscitation is to provide the optimal amount of fluid necessary to maintain end-organ perfusion and prevent burn shock. The objective of this analysis was to examine how the Burn Navigator (BN), a clinical decision support tool in burn resuscitation, was utilized across five major burn centers in the United States, using an observational trial of 300 adult patients. Subject demographics, burn characteristics, fluid volumes, urine output, and resuscitation-related complications were examined. Two hundred eighty-five patients were eligible for analysis. There was no difference among the centers on mean age (45.5 ± 16.8 years), body mass index (29.2 ± 6.9), median injury severity score (18 [interquartile range: 9-25]), or total body surface area (TBSA) (34 [25.8-47]). Primary crystalloid infusion volumes at 24 h differed significantly in ml/kg/TBSA (range: 3.1 ± 1.2 to 4.5 ± 1.7). Total fluids, including colloid, drip medications, and enteral fluids, differed among centers in both ml/kg (range: 132.5 ± 61.4 to 201.9 ± 109.9) and ml/kg/TBSA (3.5 ± 1.0 to 5.3 ± 2.0) at 24 h. Post-hoc adjustment using pairwise comparisons resulted in a loss of significance between most of the sites. There was a total of 156 resuscitation-related complications in 92 patients. Experienced burn centers using the BN successfully titrated resuscitation to adhere to 24 h goals. With fluid volumes near the Parkland formula prediction and a low prevalence of complications, the device can be utilized effectively in experienced centers. Further study should examine device utility in other facilities and on the battlefield.

Battlefield pain summit 2022: Expert consensus statements.

BACKGROUND: Battlefield pain occurs in combat casualties who experience multiple severe injuries. The nature of battlefield scenarios requires a distinct approach to battlefield pain research. A battlefield pain summit was thus convened to identify shortcomings in the current understanding of battlefield pain management, review the current state of battlefield pain research, and shape the direction of future research. METHODS: On January 10 to 11, 2022, a hybrid in-person and virtual meeting hosted by the US Army Institute of Surgical Research defined research priorities for the Combat Casualty Care Research Program's Battlefield Pain research portfolio. Summit participants identified the following key focus areas under the umbrella of battlefield pain research: battlefield injury patterns; use of ketamine and nonopioid analgesics; analgesic delivery systems; the impact of analgesia on performance, cognition, and survival; training methods; battlefield regional anesthesia; and research models. Preliminary statements presented during the summit were refined and rank ordered through a Delphi process. RESULTS: Consensus was achieved on 7 statements addressing ideal analgesic properties, delivery systems, operational performance concerns, and pain training. Ketamine was identified as safe and effective for battlefield use, and further research into nonopioid analgesics represented a high priority. CONCLUSION: The 7 consensus statements that emerged from this battlefield pain summit serve as a template to define the near-term research priorities for military-specific battlefield pain research.

Using a Normothermia Bundle With Perioperative Prewarming to Reduce Patient Hypothermia.

PURPOSE: To determine if implementing a normothermia bundle, which includes preoperative forced-air warming blankets, reduces incidence of inadvertent perioperative hypothermia (IPH). DESIGN: Intervention study using retrospective chart review. METHODS: Patients received a preoperative forced-air warming blanket and temperature management with the normothermia bundle. Temperature status data was collected from patient charts to evaluate the incidences of IPH and findings from this data analysis was used to measure improvement in perioperative temperature management. FINDINGS: Of 200 patients, 63 (31.5%) remained normothermic, 37 (18.5%) had at least one documented hypothermic temperature, and 100 (50%) had no documented temperature during the intraoperative phase of care. Although compliance with intraoperative temperature monitoring decreased by 13% postintervention, the incidence of documented IPH in reviewed records was decreased by 3.6-fold. CONCLUSION: Implementing a normothermia bundle that includes a preoperative forced-air warming blanket may lower the incidences of IPH, especially in surgical cases lasting over 120 minutes.

Abdominal Surgical Patients Randomized to Aromatherapy for Pain Management.

PURPOSE: Evaluate aromatherapy for postoperative abdominal pain in hospitalized patients. DESIGN: A randomized controlled trial design. METHODS: Study participants (n = 172) were randomized to receive either standard care or standard care and aromatherapy (AT) for postsurgical pain up to 24 hours after admission to a nonintensive care surgical unit. A convenience sample was recruited before surgery and given instructions on self-rating pain intensity. The AT group was topically administered a drop of lavender essential oil after medication and at random for pain. Pain scores and medications data were collected. FINDINGS: Of the evaluable patients (n = 147), demographic data were similar (standard care and AT groups). The use of aromatherapy showed no substantial benefit at improving pain scores or reducing medication use (the primary objectives of the study). A subgroup analysis of patients who received a regional nerve block for pain management, however, showed more than fivefold improvement in pain scores after the use of aromatherapy. The AT group used more medications at baseline (P = .032), whereas 70% less medications were used (P = .031) by 24 hours. CONCLUSIONS: Aromatherapy aided in control of pain intensity for abdominal surgical patients. In patients who received a regional nerve block, significant improvement in pain level occurred as effects of the block diminished.

The Role of the Human Microbiome in Chemical Toxicity.

There is overwhelming evidence that the microbiome must be considered when evaluating the toxicity of chemicals. Disruption of the normal microbial flora is a known effect of toxic exposure, and these disruptions may lead to human health effects. In addition, the biotransformation of numerous compounds has been shown to be dependent on microbial enzymes, with the potential for different host health outcomes resulting from variations in the microbiome. Evidence suggests that such metabolism of environmental chemicals by enzymes from the host's microbiota can affect the toxicity of that chemical to the host. Chemical-microbial interactions can be categorized into two classes: Microbiome Modulation of Toxicity (MMT) and Toxicant Modulation of the Microbiome (TMM). MMT refers to transformation of a chemical by microbial enzymes or metabolites to modify the chemical in a way that makes it more or less toxic. TMM is a change in the microbiota that results from a chemical exposure. These changes span a large magnitude of effects and may vary from microbial gene regulation, to inhibition of a specific enzyme, to the death of the microbes. Certain microbiomes or microbiota may become associated with different health outcomes, such as resistance or susceptibility to exposure to certain toxic chemicals, the ability to recover following a chemical-induced injury, the presence of disease-associated phenotypes, and the effectiveness of immune responses. Future work in toxicology will require an understanding of how the microbiome interacts with toxicants to fully elucidate how a compound will affect a diverse, real-world population.

Alterations in tissue microRNA after heat stress in the conscious rat: potential biomarkers of organ-specific injury.

BACKGROUND: Heat illness remains a significant cause of morbidity in susceptible populations. Recent research elucidating the cellular mechanism of heat stress leading to heat illness may provide information to develop better therapeutic interventions, risk assessment strategies, and early biomarkers of organ damage. microRNA (miRNA) are promising candidates for therapeutic targets and biomarkers for a variety of clinical conditions since there is the potential for high specificity for individual tissues and unique cellular functions. The objective of this study was to identify differentially expressed microRNAs and their putative mRNA targets in the heart, liver, kidney, and lung in rats at three time points: during heat stress (i.e., when core temperature reached 41.8 °C), or following a 24 or 48 h recovery period. RESULTS: Rats did not show histological evidence of tissue pathology until 48 h after heat stress, with 3 out of 6 rats showing cardiac inflammation and renal proteinosis at 48 h. The three rats with cardiac and renal pathology had 86, 7, 159, and 37 differentially expressed miRNA in the heart, liver, kidney, or lung, respectively compared to non-heat stressed control animals. During heat stress one differentially expressed miRNA was found in the liver and five in the lung, with no other modulated miRNA after 24 h or 48 h in animals with no evidence of organ injury. Pathway enrichment analysis revealed enrichment in functional pathways associated with heat stress, with the greatest effects observed in animals with histological evidence of cardiac and renal damage at 48 h. Inhibiting miR-21 in cultured cardiomyocytes increased the percent apoptotic cells five hours after heat stress from 70.9 ± 0.8 to 84.8 ± 2.2%. CONCLUSIONS: Global microRNA and transcriptomics analysis suggested that perturbed miRNA due to heat stress are involved in biological pathways related to organ injury, energy metabolism, the unfolded protein response, and cellular signaling. These miRNA may serve as biomarkers of organ injury and potential pharmacological targets for preventing heat illness or organ injury.

Comparing Surface and Intramuscular Electromyography for Simultaneous and Proportional Control Based on a Musculoskeletal Model: A Pilot Study.

Simultaneous and proportional control (SPC) of neural-machine interfaces uses magnitudes of smoothed electromyograms (EMG) as control inputs. Though surface EMG (sEMG) electrodes are common for clinical neural-machine interfaces, intramuscular EMG (iEMG) electrodes may be indicated in some circumstances (e.g., for controlling many degrees of freedom). However, differences in signal characteristics between sEMG and iEMG may influence SPC performance. We conducted a pilot study to determine the effect of electrode type (sEMG and iEMG) on real-time task performance with SPC based on a novel 2-degree-of-freedom EMG-driven musculoskeletal model of the wrist and hand. Four able-bodied subjects and one transradial amputee performed a virtual posture matching task with either sEMG or iEMG. There was a trend of better task performance with sEMG than iEMG for both able-bodied and amputee subjects, though the difference was not statistically significant. Thus, while iEMG may permit targeted recording of EMG, its signal characteristics may not be as ideal for SPC as those of sEMG. The tradeoff between recording specificity and signal characteristics is an important consideration for development and clinical implementation of SPC for neural-machine interfaces.

A Comparison of Aromatherapy to Standard Care for Relief of PONV and PDNV in Ambulatory Surgical Patients.

PURPOSE: To determine effectiveness of aromatherapy (AT) compared with standard care (SC) for postoperative and postdischarge nausea and vomiting (PONV/PDNV) in ambulatory surgical patients. DESIGN: Prospective randomized study. METHODS: Patients (n = 254) received either SC or AT for PONV and interviewed for effectiveness of PDNV. Machine learning methods (eight algorithms) were used to evaluate. FINDING: Of patients (64 of 221) that experienced PONV, 52% were in the AT group and 48% in the SC group. The majority were satisfied with treatment (timely, P = .60; effectiveness, P = .86). Of patients that experienced PDNV, treatment was 100% effective in the AT group and 67% in the SC group. The cforest algorithm was used to develop a model for predicting PONV with literature-based risk factors (0.69 area under the curve). CONCLUSIONS: AT is an effective way to manage PONV/PDNV. Gender and age were the most important predictors of PONV.

Interactions Between Transfemoral Amputees and a Powered Knee Prosthesis During Load Carriage.

Machines and humans become mechanically coupled when lower limb amputees walk with powered prostheses, but these two control systems differ in adaptability. We know little about how they interact when faced with real-world physical demands (e.g. carrying loads). Here, we investigated how each system (i.e. amputee and powered prosthesis) responds to changes in the prosthesis mechanics and gravitational load. Five transfemoral amputees walked with and without load (i.e. weighted backpack) and a powered knee prosthesis with two pre-programmed controller settings (i.e. for load and no load). We recorded subjects' kinematics, kinetics, and perceived exertion. Compared to the no load setting, the load setting reduced subjects' perceived exertion and intact-limb stance time when they carried load. When subjects did not carry load, their perceived exertion and gait performance did not significantly change with controller settings. Our results suggest transfemoral amputees could benefit from load-adaptive powered knee controllers, and controller adjustments affect amputees more when they walk with (versus without) load. Further understanding of the interaction between powered prostheses, amputee users, and various environments may allow researchers to expand the utility of prostheses beyond simple environments (e.g. firm level ground without load) that represent only a subset of real-world environments.

Potential and Actual Health Hazards in the Dense Urban Operational Environment: Critical Gaps and Solutions for Military Occupational Health.

: This paper presents environmental health risks which are prevalent in dense urban environments.We review the current literature and recommendations proposed by environmental medicine experts in a 2-day symposium sponsored by the Department of Defense and supported by the Johns Hopkins University Applied Physics Laboratory.Key hazards in the dense urban operational environment include toxic industrial chemicals and materials, water pollution and sewage, and air pollution. Four critical gaps in environmental medicine were identified: prioritizing chemical and environmental concerns, developing mobile decision aids, personalized health assessments, and better real-time health biomonitoring.As populations continue to concentrate in cities, civilian and military leaders will need to meet emerging environmental health concerns by developing and delivering adequate technology and policy solutions.

Mining kidney toxicogenomic data by using gene co-expression modules.

BACKGROUND: Acute kidney injury (AKI) caused by drug and toxicant ingestion is a serious clinical condition associated with high mortality rates. We currently lack detailed knowledge of the underlying molecular mechanisms and biological networks associated with AKI. In this study, we carried out gene co-expression analyses using DrugMatrix-a large toxicogenomics database with gene expression data from rats exposed to diverse chemicals-and identified gene modules associated with kidney injury to probe the molecular-level details of this disease. RESULTS: We generated a comprehensive set of gene co-expression modules by using the Iterative Signature Algorithm and found distinct clusters of modules that shared genes and were associated with similar chemical exposure conditions. We identified two module clusters that showed specificity for kidney injury in that they 1) were activated by chemical exposures causing kidney injury, 2) were not activated by other chemical exposures, and 3) contained known AKI-relevant genes such as Havcr1, Clu, and Tff3. We used the genes in these AKI-relevant module clusters to develop a signature of 30 genes that could assess the potential of a chemical to cause kidney injury well before injury actually occurs. We integrated AKI-relevant module cluster genes with protein-protein interaction networks and identified the involvement of immunoproteasomes in AKI. To identify biological networks and processes linked to Havcr1, we determined genes within the modules that frequently co-express with Havcr1, including Cd44, Plk2, Mdm2, Hnmt, Macrod1, and Gtpbp4. We verified this procedure by showing that randomized data did not identify Havcr1 co-expression genes and that excluding up to 10 % of the data caused only minimal degradation of the gene set. Finally, by using an external dataset from a rat kidney ischemic study, we showed that the frequently co-expressed genes of Havcr1 behaved similarly in a model of non-chemically induced kidney injury. CONCLUSIONS: Our study demonstrated that co-expression modules and co-expressed genes contain rich information for generating novel biomarker hypotheses and constructing mechanism-based molecular networks associated with kidney injury.

Repeated exposure to neurotoxic levels of chlorpyrifos alters hippocampal expression of neurotrophins and neuropeptides.

Chlorpyrifos (CPF), an organophosphorus pesticide (OP), is one of the most widely used pesticides in the world. Subchronic exposures to CPF that do not cause cholinergic crisis are associated with problems in cognitive function (i.e., learning and memory deficits), but the biological mechanism(s) underlying this association remain speculative. To identify potential mechanisms of subchronic CPF neurotoxicity, adult male Long Evans (LE) rats were administered CPF at 3 or 10mg/kg/d (s.c.) for 21 days. We quantified mRNA and non-coding RNA (ncRNA) expression profiles by RNA-seq, microarray analysis and small ncRNA sequencing technology in the CA1 region of the hippocampus. Hippocampal slice immunohistochemistry was used to determine CPF-induced changes in protein expression and localization patterns. Neither dose of CPF caused overt clinical signs of cholinergic toxicity, although after 21 days of exposure, cholinesterase activity was decreased to 58% or 13% of control levels in the hippocampus of rats in the 3 or 10mg/kg/d groups, respectively. Differential gene expression in the CA1 region of the hippocampus was observed only in the 10mg/kg/d dose group relative to controls. Of the 1382 differentially expressed genes identified by RNA-seq and microarray analysis, 67 were common to both approaches. Differential expression of six of these genes (Bdnf, Cort, Crhbp, Nptx2, Npy and Pnoc) was verified in an independent CPF exposure study; immunohistochemistry demonstrated that CRHBP and NPY were elevated in the CA1 region of the hippocampus at 10mg/kg/d CPF. Gene ontology enrichment analysis suggested association of these genes with receptor-mediated cell survival signaling pathways. miR132/212 was also elevated in the CA1 hippocampal region, which may play a role in the disruption of neurotrophin-mediated cognitive processes after CPF administration. These findings identify potential mediators of CPF-induced neurobehavioral deficits following subchronic exposure to CPF at a level that inhibits hippocampal cholinesterase to less than 20% of control. An equally significant finding is that subchronic exposure to CPF at a level that produces more moderate inhibition of hippocampal cholinesterase (approximately 50% of control) does not produce a discernable change in gene expression.

Effect of 2 Bedding Materials on Ammonia Levels in Individually Ventilated Cages.

This study sought to identify an optimal rodent bedding and cage-change interval to establish standard procedures for the IVC in our rodent vivarium. Disposable cages were prefilled with either corncob or α-cellulose bedding and were used to house 2 adult Sprague-Dawley rats (experimental condition) or contained no animals (control). Rats were observed and intracage ammonia levels measured daily for 21 d. Intracage ammonia accumulation became significant by day 8 in experimental cages containing α-cellulose bedding, whereas experimental cages containing corncob bedding did not reach detectable levels of ammonia until day 14. In all 3 experimental cages containing α-cellulose, ammonia exceeded 100 ppm (our maximum acceptable limit) by day 11. Two experimental corncob cages required changing at days 16 and 17, whereas the remaining cage containing corncob bedding lasted the entire 21 d without reaching the 100-ppm ammonia threshold. These data suggests that corncob bedding provides nearly twice the service life of α-cellulose bedding in the IVC system.

Gene Expression Patterns Associated With Histopathology in Toxic Liver Fibrosis.

Toxic industrial chemicals induce liver injury, which is difficult to diagnose without invasive procedures. Identifying indicators of end organ injury can complement exposure-based assays and improve predictive power. A multiplexed approach was used to experimentally evaluate a panel of 67 genes predicted to be associated with the fibrosis pathology by computationally mining DrugMatrix, a publicly available repository of gene microarray data. Five-day oral gavage studies in male Sprague Dawley rats dosed with varying concentrations of 3 fibrogenic compounds (allyl alcohol, carbon tetrachloride, and 4,4'-methylenedianiline) and 2 nonfibrogenic compounds (bromobenzene and dexamethasone) were conducted. Fibrosis was definitively diagnosed by histopathology. The 67-plex gene panel accurately diagnosed fibrosis in both microarray and multiplexed-gene expression assays. Necrosis and inflammatory infiltration were comorbid with fibrosis. ANOVA with contrasts identified that 51 of the 67 predicted genes were significantly associated with the fibrosis phenotype, with 24 of these specific to fibrosis alone. The protein product of the gene most strongly correlated with the fibrosis phenotype PCOLCE (Procollagen C-Endopeptidase Enhancer) was dose-dependently elevated in plasma from animals administered fibrogenic chemicals (P < .05). Semiquantitative global mass spectrometry analysis of the plasma identified an additional 5 protein products of the gene panel which increased after fibrogenic toxicant administration: fibronectin, ceruloplasmin, vitronectin, insulin-like growth factor binding protein, and α2-macroglobulin. These results support the data mining approach for identifying gene and/or protein panels for assessing liver injury and may suggest bridging biomarkers for molecular mediators linked to histopathology.

Mathematical modeling of the heat-shock response in HeLa cells.

The heat-shock response is a key factor in diverse stress scenarios, ranging from hyperthermia to protein folding diseases. However, the complex dynamics of this physiological response have eluded mathematical modeling efforts. Although several computational models have attempted to characterize the heat-shock response, they were unable to model its dynamics across diverse experimental datasets. To address this limitation, we mined the literature to obtain a compendium of in vitro hyperthermia experiments investigating the heat-shock response in HeLa cells. We identified mechanisms previously discussed in the experimental literature, such as temperature-dependent transcription, translation, and heat-shock factor (HSF) oligomerization, as well as the role of heat-shock protein mRNA, and constructed an expanded mathematical model to explain the temperature-varying DNA-binding dynamics, the presence of free HSF during homeostasis and the initial phase of the heat-shock response, and heat-shock protein dynamics in the long-term heat-shock response. In addition, our model was able to consistently predict the extent of damage produced by different combinations of exposure temperatures and durations, which were validated against known cellular-response patterns. Our model was also in agreement with experiments showing that the number of HSF molecules in a HeLa cell is roughly 100 times greater than the number of stress-activated heat-shock element sites, further confirming the model's ability to reproduce experimental results not used in model calibration. Finally, a sensitivity analysis revealed that altering the homeostatic concentration of HSF can lead to large changes in the stress response without significantly impacting the homeostatic levels of other model components, making it an attractive target for intervention. Overall, this model represents a step forward in the quantitative understanding of the dynamics of the heat-shock response.