24 research outputs found
ARFIMA-GARCH modeling of HRV: Clinical application in acute brain injury
In the last decade, several HRV based novel methodologies for describing and assessing heart rate dynamics have been proposed in the literature with the aim of risk assessment. Such methodologies attempt to describe the non-linear and complex characteristics of HRV, and hereby the focus is in two of these characteristics, namely long memory and heteroscedasticity with variance clustering. The ARFIMA-GARCH modeling considered here allows the quantification of long range correlations and time-varying volatility. ARFIMA-GARCH HRV analysis is integrated with multimodal brain monitoring in several acute cerebral phenomena such as intracranial hypertension, decompressive craniectomy and brain death. The results indicate that ARFIMA-GARCH modeling appears to reflect changes in Heart Rate Variability (HRV) dynamics related both with the Acute Brain Injury (ABI) and the medical treatments effects. (c) 2017, Springer International Publishing AG
Epithelial apoptosis in mechanistically distinct methods of injury in the murine small intestine
Gut epithelial apoptosis is involved in the
pathophysiology of multiple diseases. This study
characterized intestinal apoptosis in three
mechanistically distinct injuries with different kinetics of
cell death. FVB/N mice were subjected to gamma
radiation, Pseudomonas aeruginosa pneumonia or
injection of monoclonal anti-CD3 antibody and
sacrificed 4, 12, or 24 hours post-injury (n=10/time
point). Apoptosis was quantified in the jejunum by
hematoxylin and eosin (H&E), active caspase-3,
terminal deoxynucleotidyl transferase dUTP-mediated
nick end labeling (TUNEL), in situ oligoligation reaction
(ISOL,) cytokeratin 18, and annexin V staining.
Reproducible results were obtained only for H&E, active
caspase-3, TUNEL and ISOL, which were quantified
and compared against each other for each injury at each
time point. Kinetics of injury were different with early
apoptosis highest following radiation, late apoptosis
highest following anti CD3, and more consistent levels
following pneumonia. ISOL was the most consistent
stain and was always statistically indistinguishable from
at least 2 stains. In contrast, active caspase-3
demonstrated lower levels of apoptosis, while the
TUNEL assay had higher levels of apoptosis in the most
severely injured intestine regardless of mechanism of
injury. H&E was a statistical outlier more commonly mechanism or kinetics of injury, ISOL correlates to other
quantification methods of detecting gut epithelial
apoptosis more than any other method studied and
compares favorably to other commonly accepted
techniques of quantifying apoptosis in a large intestinal
cross sectional by balancing sensitivity and specificity
across a range of times and levels of death
Neutrophil depletion causes a fatal defect in murine pulmonary Staphylococcus aureus clearance
BACKGROUND: Staphylococcus aureus is the most common cause of healthcare-associated pneumonia. Despite the significant morbidity and mortality associated with the disease, animal models of S. aureus pneumonia are rare. MATERIALS AND METHODS: We examined the pathogenicity of four different strains of S. aureus (both methicillin-sensitive and resistant as well as Panton-Valentine leukocidin positive and negative) in four strains of immunocompetent inbred and outbred mice (FVB/N, C57Bl/6, Balb/c, ND4, n=148). The immunologic basis for the development of murine S. aureus pneumonia was then determined by selectively depleting neutrophils, lymphocytes, or pulmonary macrophages prior to the onset of infection. An additional cohort of animals was rendered immunosuppressed by induction of abdominal sepsis via cecal ligation and puncture 2, 4 or 7 days prior to the onset of pneumonia. RESULTS: Nearly all immunocompetent mice survived, regardless of which strain of S. aureus was used or which strain of mouse was infected. Among animals with immune depletion or prior immunosuppression, survival was decreased only following neutrophil depletion (26% vs. 90% alive at 7 days, p<0.0001). Compared to immunocompetent animals, neutrophil-depleted mice with S. aureus pneumonia had delayed pulmonary bacterial clearance at 16 and 40 hours but had no difference in levels of bacteremia. Neutrophil-depleted mice also had elevated levels of pulmonary MCP-1 (822 pg/ml vs. 150 pg/ml, p<0.05). In contrast, pulmonary histologic appearance was similar in both groups as was dry/wet lung weight. CONCLUSIONS: These results suggest that neutrophils play a critical role in the host response to S. aureus pneumonia, and the survival differences observed in neutrophil-depleted mice are associated with alterations in bacterial clearance and pulmonary cytokine response
Epidemiology of infections with cytomegalovirus (CMV) and herpes simplex virus in promiscuous women: absence of exogenous reinfection with CMV.
The relationship between blood lactate and survival following the use of adrenaline in the treatment of septic shock
This prospective observational study evaluates the relationship between adrenaline, lactate and intensive care unit survival in septic shock. Forty patients requiring adrenaline therapy for a first episode of septic shock acquired >24 hours after admission to the intensive care unit had blood lactate levels measured two-hourly over a 24-hour period. Adrenaline therapy was escalated until target mean arterial pressure was reached. The lactate index was calculated as the ratio of maximum lactate increase to the adrenaline increase. Lactate increased from 2.3 to 2.9 mmol.l (P=0.024) and the mean adrenaline increase was 0.14 μg.kg.minute. Peak lactate correlated with peak adrenaline (rho=0.34, P=0.032). Lactate index was the only independent predictor of survival after controlling for age and Acute Physiological and Chronic Health Evaluation II score (odds ratio 1.14, 95% confidence interval 1.03 to 1.26, P=0.009). A high lactate following adrenaline administration may be a beneficial and appropriate response