Enzymatic changes in serum and cerebrospinal fluid in neurological injury

Creatine kinase and its isoenzymes in the serum and cerebrospinal fluid of healthy canines

BACKGROUND

Creatine kinase (CK) exists as three isoenzymes (CK-MM, CK-MB, and CK-BB) that are predominantly expressed in specific tissues and can be detected in both the serum and cerebrospinal fluid (CSF). CSF CK has been relatively unstudied in veterinary medicine, although studies in human medicine have demonstrated that changes in total CSF CK activity can indicate neurologic abnormalities.

OBJECTIVES

The purpose of this study was to establish reference intervals for CK and its three major isoenzymes in the serum and CSF of clinically healthy dogs. By establishing a definitive reference interval for this enzyme in healthy canines, the diagnostic use and possible significance of CK in clinical disease can be studied.

METHODS

Serum and/or CSF were collected from healthy dogs. Total CK activity was measured spectrophotometrically, and isoenzyme distributions were determined using the QuickGel CK Vis Isoenzyme Kit and a densitometric scanner. Total CK and CK isoenzyme activities were determined within 8 h of collection.

RESULTS

The median serum total CK in healthy canines was 159.0 U/L (range: 53.0-539.0 U/L), while the median CSF total CK was 3.7 U/L (range: 2.0-84.0 U/L). CK-BB and CK-MM were approximately equal in the serum, while CK-MM was the predominant isoenzyme in the CSF.

CONCLUSIONS

Knowledge of the normal distribution and concentration of CK in canine serum and CSF will set the foundation for future studies of canine CK as a potentially clinically useful biomarker.

Biochemical and Radiological Factors for Prognostication of Traumatic Brain Injury: An Institutional Experience

Introduction Traumatic brain injury (TBI) necessitates identifying patients at risk of fatal outcomes. Classic biomarkers used clinically today in other organ systems are quantitative in nature. This aspect largely restricts the prognostic ability of a theoretical quantitative brain biomarker. This study aimed to explore biochemical markers and imaging findings reflecting the severity of cerebral damage to predict outcomes. Methodology In this study, 61 TBI cases with moderate to severe brain injury were prospectively observed, and various indices including random blood sugar (RBS), hemoglobin, international normalized ratio (INR), lactate dehydrogenase (LDH), cortisol, and CT findings were assessed. Glasgow Outcome Scores (GOS) determined the outcomes. Statistical analysis was carried out to assess correlations.  Results The mean RBS level of those who did not survive was 259.58 mg/dL, whereas in those who survived the value was 158.48 mg/dL. Analysis indicated that patients with high RBS value on admission had a higher risk of mortality (p=0.000). We noted that the mean serum cortisol levesl on both Days 1 and 5 were higher in patients who died and were able to establish a statistically significant correlation between both the values and outcome. A statistically significant negative correlation between Day 1 and Day 5 serum LDH levels and outcomes was evident from our study (p=0.000 for both). Among the components of the Rotterdam score, the presence of intraventricular hemorrhage (IVH) in the CT scan had a significant association with unfavorable outcomes (p=0.01) while midline shift was significantly associated with a low GCS (p=0.04). Conclusion Biochemical markers such as INR, RBS, serum cortisol, and LDH at admission can serve as valuable indicators of prognosis in TBI patients. Furthermore, a persistent increase in LDH and cortisol levels between Days 1 and 5, along with the Glasgow Coma Scale and Rotterdam Scoring system, are good predictors of mortality.

Effect of Cerebral Ischemic Strokes in Different Cerebral Artery Regions on Left Ventricular Function

Objectives

The relationship between cerebral ischemic stroke and left ventricular function evaluated by echocardiography has been emphasized. Whether lesions in different cerebral artery regions would result in left ventricular dysfunction remains uncertain.

Methods

Patients were divided into middle cerebral artery (MCA) (n = 79), posterior cerebral artery (PCA) (n = 64), basilar artery (BA) regions (n = 66), and no-ischemic stroke group (n = 209). We retrospectively collected demographic characteristics, hematologic parameters, and ECG results, and a comparison of echocardiographic parameters was performed to determine the relationship between ischemic stroke and left ventricular function.

Results

A total of 418 patients were included. Demographic characteristics did not significantly differ between the ischemic stroke and non-ischemic stroke groups, except for a history of drinking (p < 0.001). Homocysteine levels in the MCA group were higher than those in the PCA and BA groups (p < 0.05). The highly sensitive C-reactive protein (hs-CRP) level was higher in the ischemic stroke group than in the non-ischemic stroke one (p = 0.001). A higher incidence of ST-T changes in the ECG and lower levels of potassium and magnesium in the ischemic stroke group were found. Significant differences in diastolic function between groups were noted, and the early mitral inflow velocity, annular early diastolic velocity, and ratio between the mitral annular early diastolic velocity and mitral annulus atrial inflow velocity in the MCA group were lower than those in the BA group (p < 0.05).

Conclusions

Ischemic strokes exhibited a negative effect on left ventricular diastolic function by echocardiography, especially in MCA region infarcts. These results are of great importance for neurologists as they highlight the need for left ventricular function evaluation after stroke to regulate therapy strategies in time.

Forensic biomarkers of lethal traumatic brain injury

Traumatic brain injury (TBI) is a major cause of death and its accurate diagnosis is an important concern of daily forensic practice. However, it can be challenging to diagnose TBI in cases where macroscopic signs of the traumatic head impact are lacking and little is known about the circumstances of death. In recent years, several post-mortem studies investigated the possible use of biomarkers for providing objective evidence for TBIs as the cause of death or to estimate the survival time and time since death of the deceased. This work systematically reviewed the available scientific literature on TBI-related biomarkers to be used for forensic purposes. Post-mortem TBI-related biomarkers are an emerging and promising resource to provide objective evidence for cause of death determinations as well as survival time and potentially even time since death estimations. This literature review of forensically used TBI-biomarkers revealed that current markers have low specificity for TBIs and only provide limited information with regards to survival time estimations and time since death estimations. Overall, TBI fatality-related biomarkers are largely unexplored in compartments that are easily accessible during autopsies such as urine and vitreous humor. Future research on forensic biomarkers requires a strict distinction of TBI fatalities from control groups, sufficient sample sizes, combinations of currently established biomarkers, and novel approaches such as metabolomics and mi-RNAs.

Impact of REM sleep deprivation and sleep recovery on circulatory neuroinflammatory markers

Objectives

Sleep loss may contribute to neuroinflammation, which might increase neuroinflammatory markers such as neuron-specific enolase (NSE), creatine kinase-brain fraction (CK-BB), lactate dehydrogenase brain fraction (LDH-BB) in blood. Hence, we evaluated the effect of REM sleep deprivation and recovery on these markers.

Material and Methods

Twenty-four adult male Sprague Dawley rats were grouped as control, environmental control, REM sleep deprivation, and 24 hour sleep recovery. The rats were sleep deprived for 72 hours and recovered for 24 hours. NSE, CK-BB, and LDH-BB levels in serum were measured using ELISA.

Results

The serum NSE, CK-BB, and LDH-BB were significantly higher in 72 hour sleep deprived group compared to control (p<0.01). After 24 hours of sleep recovery, the levels of NSE, CK-BB, and LDH-BB were comparable to control (p>0.05).

Discussion

REM sleep deprivation increased serum NSE, CK-BB, and LDH-BB, which might be due to neural damage. However, 24 hours of sleep recovery restored these markers.

Penetrating Traumatic Brain Injury Triggers Dysregulation of Cathepsin B Protein Levels Independent of Cysteine Protease Activity in Brain and Cerebral Spinal Fluid

Cathepsin B (CatB), a lysosomal cysteine protease, is important to brain function and may have dual utility as a peripheral biomarker of moderate-severe traumatic brain injury (TBI). The present study determined levels of pro- and mature (mat) CatB protein as well as cysteine protease activity within the frontal cortex (FC; proximal injury site), hippocampus (HC; distal injury site), and cerebral spinal fluid (CSF) collected 1-7 days after craniotomy and penetrating ballistic-like brain injury (PBBI) in rats. Values were compared with naïve controls. Further, the utility of CatB protein as a translational biomarker was determined in CSF derived from patients with severe TBI. Craniotomy increased matCatB levels in the FC and HC, and led to elevation of HC activity at day 7. PBBI caused an even greater elevation in matCatB within the FC and HC within 3-7 days. After PBBI, cysteine protease activity peaked at 3 days in the FC and was elevated at 1 day and 7 days, but not 3 days, in the HC. In rat CSF, proCatB, matCatB, and cysteine protease activity peaked at 3 days after craniotomy and PBBI. Addition of CA-074, a CatB-specific inhibitor, confirmed that protease activity was due to active matCatB in rat brain tissues and CSF at all time-points. In patients, CatB protein was detectable from 6 h through 10 days after TBI. Notably, CatB levels were significantly higher in CSF collected within 3 days after TBI compared with non-TBI controls. Collectively, this work indicates that CatB and its cysteine protease activity may serve as collective molecular signatures of TBI progression that differentially vary within both proximal and distal brain regions. CatB and its protease activity may have utility as a surrogate, translational biomarker of acute-subacute TBI.

Plasma metabolomic biomarkers accurately classify acute mild traumatic brain injury from controls

Past and recent attempts at devising objective biomarkers for traumatic brain injury (TBI) in both blood and cerebrospinal fluid have focused on abundance measures of time-dependent proteins. Similar independent determinants would be most welcome in diagnosing the most common form of TBI, mild TBI (mTBI), which remains difficult to define and confirm based solely on clinical criteria. There are currently no consensus diagnostic measures that objectively define individuals as having sustained an acute mTBI. Plasma metabolomic analyses have recently evolved to offer an alternative to proteomic analyses, offering an orthogonal diagnostic measure to what is currently available. The purpose of this study was to determine whether a developed set of metabolomic biomarkers is able to objectively classify college athletes sustaining mTBI from non-injured teammates, within 6 hours of trauma and whether such a biomarker panel could be effectively applied to an independent cohort of TBI and control subjects.

A 6-metabolite panel was developed from biomarkers that had their identities confirmed using tandem mass spectrometry (MS/MS) in our Athlete cohort. These biomarkers were defined at ≤6 hours following mTBI and objectively classified mTBI athletes from teammate controls, and provided similar classification of these groups at the 2, 3, and 7 days post-mTBI. The same 6-metabolite panel, when applied to a separate, independent cohort provided statistically similar results despite major differences between the two cohorts. Our confirmed plasma biomarker panel objectively classifies acute mTBI cases from controls within 6 hours of injury in our two independent cohorts. While encouraged by our initial results, we expect future studies to expand on these initial observations.

A blood-based biomarker panel to risk-stratify mild traumatic brain injury

Mild traumatic brain injury (TBI) accounts for the vast majority of the nearly two million brain injuries suffered in the United States each year. Mild TBI is commonly classified as complicated (radiographic evidence of intracranial injury) or uncomplicated (radiographically negative). Such a distinction is important because it helps to determine the need for further neuroimaging, potential admission, or neurosurgical intervention. Unfortunately, imaging modalities such as computed tomography (CT) and magnetic resonance imaging (MRI) are costly and not without some risk. The purpose of this study was to screen 87 serum biomarkers to identify a select panel of biomarkers that would predict the presence of intracranial injury as determined by initial brain CT. Serum was collected from 110 patients who sustained a mild TBI within 24 hours of blood draw. Two models were created. In the broad inclusive model, 72kDa type IV collagenase (MMP-2), C-reactive protein (CRP), creatine kinase B type (CKBB), fatty acid binding protein-heart (hFABP), granulocyte-macrophage colony-stimulating factor (GM-CSF) and malondialdehyde modified low density lipoprotein (MDA-LDL) significantly predicted injury visualized on CT, yielding an overall c-statistic of 0.975 and a negative predictive value (NPV) of 98.6. In the parsimonious model, MMP-2, CRP, and CKBB type significantly predicted injury visualized on CT, yielding an overall c-statistic of 0.964 and a negative predictive value (NPV) of 97.2. These results suggest that a serum based biomarker panel can accurately differentiate patients with complicated mild TBI from those with uncomplicated mild TBI. Such a panel could be useful to guide early triage decisions, including the need for further evaluation or admission, especially in those environments in which resources are limited.

Expression and location of HSP60 and HSP10 in the heart tissue of heat-stressed rats

The present study aimed to analyze the expression levels and localizations of heat shock protein (HSP) 60 and HSP10 in the heart tissue of rats subjected to heat stress (42°C) for 0, 20, 80 and 100 min. Histopathological injuries and increased serum activities of serum lactate dehydrogenase and creatine kinase isoenzyme MB were detected in the heated rat myocardial cells. These results suggested that heat stress-induced acute degeneration may be sufficient to cause sudden death in animals by disrupting the function and permeability of the myocardial cell membrane. In addition, the expression levels of HSP60 were significantly increased following 20 min heat stress, whereas the expression levels of its cofactor HSP10 were not. Furthermore, the location of HSP60, but not of HSP10, was significantly altered during periods of heat stress. These results suggested that HSP60 in myocardial tissue may be more susceptive to the effects of heat stress as compared with HSP10, and that HSP10 is constitutively expressed in the heart of rats. The expression levels and localizations of HSP60 and HSP10 at the different time points of heat stress were not similar, which suggested that HSP60 and HSP10 may not form a complex in the heart tissue of heat-stressed rats.

Central Nervous System and Vertebrae Development in Horses: a Chronological Study with Differential Temporal Expression of Nestin and GFAP

The neural system is one of the earliest systems to develop and the last to be fully developed after birth. This study presents a detailed description of organogenesis of the central nervous system (CNS) at equine embryonic/fetal development between 19 and 115 days of pregnancy. The expression of two important biomarkers in the main structure of the nervous system responsible for neurogenesis in the adult individual, and in the choroid plexus, was demonstrated by Nestin and glial fibrillary acid protein (GFAP) co-labeling. In the 29th day of pregnancy in the undifferentiated lateral ventricle wall, the presence of many cells expressing Nestin and few expressing GFAP was observed. After the differentiation of the lateral ventricle wall zones at 60 days of pregnancy, the subventricular zone, which initially had greater number of Nestin⁺ cells, began to show higher numbers of GFAP⁺ cells at 90 days of pregnancy. A similar pattern was observed for Nestin⁺ and GFAP⁺ cells during development of the choroid plexus. This study demonstrates, for the first time, detailed chronological aspects of the equine central nervous system organogenesis associated with downregulation of Nestin and upregulation of GFAP expression.

Current status of fluid biomarkers in mild traumatic brain injury

Mild traumatic brain injury (mTBI) affects millions of people annually and is difficult to diagnose. Mild injury is insensitive to conventional imaging techniques and diagnoses are often made using subjective criteria such as self-reported symptoms. Many people who sustain a mTBI develop persistent post-concussive symptoms. Athletes and military personnel are at great risk for repeat injury which can result in second impact syndrome or chronic traumatic encephalopathy. An objective and quantifiable measure, such as a serum biomarker, is needed to aid in mTBI diagnosis, prognosis, return to play/duty assessments, and would further elucidate mTBI pathophysiology. The majority of TBI biomarker research focuses on severe TBI with few studies specific to mild injury. Most studies use a hypothesis-driven approach, screening biofluids for markers known to be associated with TBI pathophysiology. This approach has yielded limited success in identifying markers that can be used clinically, additional candidate biomarkers are needed. Innovative and unbiased methods such as proteomics, microRNA arrays, urinary screens, autoantibody identification and phage display would complement more traditional approaches to aid in the discovery of novel mTBI biomarkers.

Biomarkers in traumatic brain injury: a review

Biomarkers allow physiological processes to be monitored, in both health and injury. Multiple attempts have been made to use biomarkers in traumatic brain injury (TBI). Identification of such biomarkers could allow improved understanding of the pathological processes involved in TBI, diagnosis, prognostication and development of novel therapies. This review article aims to cover both established and emerging TBI biomarkers along with their benefits and limitations. It then discusses the potential value of TBI biomarkers to military, civilian and sporting populations and the future hopes for developing a role for biomarkers in head injury management.

Biomarkers of Brain Injury in Cerebral Infections

BACKGROUND

Central nervous system (CNS) infections present a major burden of disease worldwide and are associated with high rates of mortality and morbidity. Swift diagnosis and initiation of appropriate treatment are vital to minimize the risk of poor outcome; however, tools are lacking to accurately diagnose infection, assess injury severity, and predict outcome. Biomarkers of structural neurological injury could provide valuable information in addressing some of these challenges.

CONTENT

In this review, we summarize experimental and clinical research on biomarkers of neurological injury in a range of CNS infectious diseases. Data suggest that in both adults and children, the biomarkers S100B and neuron-specific enlose (NSE), among others, can provide insight into the pathophysiology of CNS infection and injury severity, evolution, and response to treatment. Research into the added utility of combining a panel of biomarkers and in assessing biomarker association with clinical and radiological outcomes warrants further work. Various factors, including age, the establishment of normative values, and comparison of biomarker concentrations across different testing platforms still present challenges in biomarker application.

SUMMARY

Research regarding the value of biomarkers in CNS infections is still in its infancy. However, early evidence supports their utility in diagnosis and prognosis, and potentially as effective surrogate end points in the assessment of novel interventions.

Addressing the needs of traumatic brain injury with clinical proteomics

Background

Neurotrauma or injuries to the central nervous system (CNS) are a serious public health problem worldwide. Approximately 75% of all traumatic brain injuries (TBIs) are concussions or other mild TBI (mTBI) forms. Evaluation of concussion injury today is limited to an assessment of behavioral symptoms, often with delay and subject to motivation. Hence, there is an urgent need for an accurate chemical measure in biofluids to serve as a diagnostic tool for invisible brain wounds, to monitor severe patient trajectories, and to predict survival chances. Although a number of neurotrauma marker candidates have been reported, the broad spectrum of TBI limits the significance of small cohort studies. Specificity and sensitivity issues compound the development of a conclusive diagnostic assay, especially for concussion patients. Thus, the neurotrauma field currently has no diagnostic biofluid test in clinical use.

Content

We discuss the challenges of discovering new and validating identified neurotrauma marker candidates using proteomics-based strategies, including targeting, selection strategies and the application of mass spectrometry (MS) technologies and their potential impact to the neurotrauma field.

Summary

Many studies use TBI marker candidates based on literature reports, yet progress in genomics and proteomics have started to provide neurotrauma protein profiles. Choosing meaningful marker candidates from such ‘long lists’ is still pending, as only few can be taken through the process of preclinical verification and large scale translational validation. Quantitative mass spectrometry targeting specific molecules rather than random sampling of the whole proteome, e.g., multiple reaction monitoring (MRM), offers an efficient and effective means to multiplex the measurement of several candidates in patient samples, thereby omitting the need for antibodies prior to clinical assay design. Sample preparation challenges specific to TBI are addressed. A tailored selection strategy combined with a multiplex screening approach is helping to arrive at diagnostically suitable candidates for clinical assay development. A surrogate marker test will be instrumental for critical decisions of TBI patient care and protection of concussion victims from repeated exposures that could result in lasting neurological deficits.

Perspectives on molecular biomarkers of oxidative stress and antioxidant strategies in traumatic brain injury

Traumatic brain injury (TBI) is frequently associated with abnormal blood-brain barrier function, resulting in the release of factors that can be used as molecular biomarkers of TBI, among them GFAP, UCH-L1, S100B, and NSE. Although many experimental studies have been conducted, clinical consolidation of these biomarkers is still needed to increase the predictive power and reduce the poor outcome of TBI. Interestingly, several of these TBI biomarkers are oxidatively modified to carbonyl groups, indicating that markers of oxidative stress could be of predictive value for the selection of therapeutic strategies. Some drugs such as corticosteroids and progesterone have already been investigated in TBI neuroprotection but failed to demonstrate clinical applicability in advanced phases of the studies. Dietary antioxidants, such as curcumin, resveratrol, and sulforaphane, have been shown to attenuate TBI-induced damage in preclinical studies. These dietary antioxidants can increase antioxidant defenses via transcriptional activation of NRF2 and are also known as carbonyl scavengers, two potential mechanisms for neuroprotection. This paper reviews the relevance of redox biology in TBI, highlighting perspectives for future studies.

Protective effects of minocycline against short-term ischemia-reperfusion injury in rat brain

The aim of this study was to assess the effects of minocycline on cerebral ischemia-reperfusion (I/R) injury in rats. The study was carried out on 24 male Wistar albino rats, weighing 200-250 g, which were divided into three groups: (i) control (n = 8), (ii) I/R (n = 8) and (iii) I/R + minocycline (n = 8). Minocycline was administrated at a dose of 90 mg/kg p.o. to the I/R group 48, 24 and 1 h before ischemia. Following bilateral exposure of the common carotid arteries by anterior cervical dissection and separation of the vagus nerve, I/R injury was performed by occlusion. Following reperfusion, malondialdehyde (MDA), superoxide dismutase, glutathione peroxidase and catalase levels in the blood and brain tissue, and creatine kinase (CK), CK-BB, lactate dehydrogenase (LDH), neuron-specific enolase (NSE) and protein S100β levels in the blood were measured and the histopathological changes were monitored. Regarding histopathological evaluation, symptoms of degeneration were significantly improved in the I/R + minocycline group compared to the I/R-only group. Statistical analysis of the biochemical parameters revealed significant differences in MDA (p < 0.001), nitric oxide (p < 0.05), CK (p < 0.05) and CK-MB (p < 0.05) levels between the I/R + minocycline group and the I/R group. According to the literature, the effect of minocycline is firstly assessed by LDH, CK-MB, NSE and S-100β analysis in addition to antioxidant status and histopathological analysis.

Predictive biomarkers of recovery in traumatic brain injury

Recent advances in medicine, intensive care and diagnostic imaging modalities have led to a pronounced reduction in deaths and disability resulting from traumatic brain injury. However, there are not sufficient findings to evaluate and quantify the severity of the initial and secondary processes destructive and therefore there are not effective therapeutic measures to effectively predict the outcome. For this reason, in recent decades, researchers and clinicians have focused on specific markers of cellular brain injury to improve the diagnosis and the evaluation of outcome. Many proteins synthesized in the astroglia cells or in the neurons, such as neuron-specific enolase, S100 calcium binding protein B, myelin basic protein, creatine kinase brain isoenzyme, glial fibrillary acidic protein, plasma desoxyribonucleic acid, brain-derived neurotrophic factor, and ubiquitin carboxy-terminal hydrolase-L1, have been proposed as potential markers for cell damage in central nervous system. Usually, the levels of these proteins increase following brain injury and are found in increasing concentrations in the cerebrospinal fluid depending on the injury magnitude, and can also be found in blood stream because of a compromised blood-brain barrier. In this review, we examine the various factors that must be taken into account in the search for a reliable non-invasive biomarkers in traumatic brain injury and their role in the diagnosis and outcome evaluation.

Serum biomarkers of neurologic injury in cardiac operations

Assessment of subtle neurocognitive decline after surgical procedures has been hampered by heterogeneous testing techniques and a lack of reproducibility. This review summarizes the sensitivity and specificity of biomarkers of neurologic injury to determine whether they can be applied in the postoperative period to accurately predict neurocognitive decline. Creatine kinase-brain type, neuron-specific enolase, and S100B can be released into serum during operations by extracranial sources. Glial fibrillary acidic protein is a sensitive marker, and there are extracranial sources that are antigenically different from the brain-derived form. Serum levels of tau protein after acute neurologic injury do not reliability correlate with incidence.

Plasma heart-type fatty acid binding protein level in acute ischemic stroke: comparative analysis with plasma S100B level for diagnosis of stroke and prediction of long-term clinical outcome

OBJECTIVES

Heart-type fatty acid binding protein (H-FABP) is enriched in neuronal cell body as well as myocardium, and is rapidly released from damaged neuron into circulation in cerebral ischemia. We performed a comparative analysis between plasma H-FABP and S100B levels in the acute phase of ischemic stroke.

METHODS

The present study included 111 consecutive patients with acute ischemic stroke and 127 control subjects. Measurement of plasma H-FABP and S100B levels was conducted during acute phase (<24 h) of stroke. Clinical severities were evaluated by the use of NIHSS scores at admission and mRS score at 3 months after symptom onset.

RESULTS

Both the plasma H-FABP and S100B levels were significantly higher in stroke group than control group. In multiple logistic regression analysis, statistical significance of both markers remained significant after adjusting the vascular risk factors. In the receiver operator characteristic (ROC) curve analysis, neither H-FABP (area under curve [AUC]=0.71, P<0.001, sensitivity: 59.5%, specificity: 79.5%) nor S100B (AUC=0.70, P<0.001, sensitivity: 54.0%, specificity: 83.5%) showed a favorable degree of diagnostic value to discriminate stroke from stroke mimic. Plasma H-FABP (r=0.46, P<0.01) and S100B (r=0.45, P<0.01) were correlated with initial NIHSS score, and both marker were significantly higher in patients with poor clinical outcome.

CONCLUSION

Although plasma H-FABP is elevated in the acute phase of ischemic stroke, the diagnostic accuracy of H-FABP as a sole marker is not sufficient to be applied in the clinical setting. Plasma H-FABP can be used as a potential marker for stroke prognosis.

Rapid analytical methods for on-site triage for traumatic brain injury

Traumatic brain injury (TBI) results from an event that causes rapid acceleration and deceleration of the brain or penetration of the skull with an object. Responses to stimuli and questions, loss of consciousness, and altered behavior are symptoms currently used to justify brain imaging for diagnosis and therapeutic guidance. Tests based on such symptoms are susceptible to false-positive and false-negative results due to stress, fatigue, and medications. Biochemical markers of neuronal damage and the physiological response to that damage are being identified. Biosensors capable of rapid measurement of such markers in the circulation offer a solution for on-site triage, as long as three criteria are met: (a) Recognition reagents can be identified that are sufficiently sensitive and specific, (b) the biosensor can provide quantitative assessment of multiple markers rapidly and simultaneously, and (c) both the sensor and reagents are designed for use outside the laboratory.

Enzyme-based NAND gate for rapid electrochemical screening of traumatic brain injury in serum

We report on the development of a rapid enzyme logic gate-based electrochemical assay for the assessment of traumatic brain injury (TBI). The concept harnesses a biocatalytic cascade that emulates the functionality of a Boolean NAND gate in order to process relevant physiological parameters in the biochemical domain. The enzymatic backbone ensures that a high-fidelity diagnosis of traumatic brain injury can be tendered in a rapid fashion when the concentrations of key serum-based biomarkers reach pathological levels. The excitatory neurotransmitter glutamate and the enzyme lactate dehydrogenase were used here as clinically-relevant input TBI biomarkers, in connection to the low-potential detection of the NADH product in the presence of methylene green at a glassy carbon electrode. A systematic optimization of the gate and the entire protocol has resulted in the effective discrimination between the physiological and pathological logic levels. Owing to its robust design, the enzyme-based logic gate mitigates potential interferences from both physiological and electroactive sources and is able to perform direct measurements in human serum samples. Granted further detailed clinical validation, this proof-of-concept study demonstrates the potential of the electrochemical assay to aid in the rapid and decentralized diagnosis of TBI.

Time-dependent changes in serum biomarker levels after blast traumatic brain injury

Neuronal and glial proteins detected in the peripheral circulating blood after injury can reflect the extent of the damage caused by blast traumatic brain injury (bTBI). The temporal pattern of their serum levels can further predict the severity and outcome of the injury. As part of characterizing a large-animal model of bTBI, we determined the changes in the serum levels of S100B, neuron-specific enolase (NSE), myelin basic protein (MBP), and neurofilament heavy chain (NF-H). Blood samples were obtained prior to injury and at 6, 24, 72 h, and 2 weeks post-injury from animals with different severities of bTBI; protein levels were determined using reverse phase protein microarray (RPPM) technology. Serum levels of S100B, MBP, and NF-H, but not NSE, showed a time-dependent increase following injury. The detected changes in S100B and MBP levels showed no correlation with the severity of the injury. However, serum NF-H levels increased in a unique, rapid manner, peaking at 6 h post-injury only in animals exposed to severe blast with poor clinical and pathological outcomes. We conclude that the sudden increase in serum NF-H levels following bTBI may be a useful indicator of injury severity. If additional studies verify our findings, the observed early peak of serum NF-H levels can be developed into a useful diagnostic tool for predicting the extent of damage following bTBI.

Clinical applications of biomarkers in pediatric traumatic brain injury

INTRODUCTION

The diagnosis, treatment, and prediction of outcome in pediatric traumatic brain injury (TBI) present significant challenges to the treating clinician. Clinical and radiological tools for assessing injury severity and predicting outcome, in particular, lack sensitivity and specificity. In patients with mild TBI, often there is uncertainty about which patients should undergo radiological imaging and who is at risk for long term neurological sequelae. In severe TBI, often there is uncertainty about which patients will experience secondary insults and what the outcome for individual patients will be. In several other clinical specialties, biomarkers are used to diagnose disease, direct treatment, and prognosticate. However, an ideal biomarker for brain injury has not been found.

METHODS

In this review, we examine the various factors that must be taken into account in the search for a reliable biomarker in brain injury. We review the important studies that have investigated common biomarkers of structural brain injury, in particular S100B, neuron-specific enolase, myelin basic protein, and glial fibrillary acid protein.

DISCUSSION

The potential uses and limitations of these biomarkers in the context of TBI are discussed.

[Influence of age, gender, and severity on recovery of patients with brain injury]

PURPOSE

This study was conducted to investigate the individual and cross influences of age, gender, and severity on recovery of patients with brain injury.

METHODS

For the purpose of the study, traumatic or spontaneous brain injury patients admitted to the intensive care unit (ICU) were conveniently selected. The data regarding outcomes were collected 3 months after admission.

RESULTS

Individual influences of the study variables on patients' recovery were significant, except for gender. But while the individual influence of gender on recovery was not significant, cross influence of gender and age was significant, but only for the sub-dimension of 'arousalbility and awareness'. The study results also showed that 3-way cross influence of gender, age, and severity was only significant on the sub-dimension of 'arousalbility and awareness'.

CONCLUSION

The sub-dimension of recovery cross influenced by the demographic factors of gender and age, and severity was 'arousalbility and awareness'. This might indicate that the study variables that cross influencing recovery had more influence on consciousness compared to physical function and psycho-social adaptation.

Cerebrospinal creatinine kinase level in children with meningitis

BACKGROUND

The aim of this study is to evaluate the diagnostic value of the enzyme creatine kinase (CK) in the cerebrospinal fluid (CSF) of children with meningitis.

METHOD

CSF samples were collected from seventy one children suspected of having meningitis. The levels of total CK, CK-BB, Glucose, total protein, WBC counts, and culture were determined in the CSF. The cutoff value for total CK in the CSF was defined as 18 U/L.

RESULTS

Three cases (4%) of bacterial meningitis and 11 cases (15%) of aseptic meningitis were confirmed by culture. The sensitivity and specificity of total CK CSF level alone to diagnose bacterial meningitis were found to be 33% and 91% respectively. The positive and negative predictive values were found to be 14% and 98% respectively. On the other hand, the sensitivity and specificity of total CK level in aseptic meningitis were found to be 40% and 98% respectively and the positive and negative predictive values were 86% and 94% respectively. The sensitivity and specificity of total protein and glucose in CSF were also calculated. Streptococcus pneumonia and homophiles influenza were the main types identified in our cases.

DISCUSSION AND CONCLUSION

Measuring the total CK level in the CSF may be very useful in diagnosis of meningitis if only combined with other CSF markers. It is not of any much benefit if it is used solely.

The CSF creatine kinase-BB isoenzyme activity in experimental lumbar spinal stenosis model

STUDY DESIGN

An investigation of creatine kinase (CK)-BB isoenzyme activity in cerebrospinal fluid (CSF) of the rabbits after experimentally induced spinal stenosis.

OBJECTIVES

To create a lumbar spinal stenosis (LSS) model at conus medullaris level without laminectomy in rabbits and to investigate the importance of CK-BB isoenzyme activity in CSF associated with electrophysiologic and histopathologic changes in the spinal cord.

SUMMARY OF BACKGROUND DATA

LSS is a disorder characterized by leg pain and difficulty of walking. Narrowing of the spinal canal and compression on the spinal cord and nerves are the main features of spinal stenosis.

METHODS

Fifteen male albino rabbits were used in this study. A reproducible, subacute LSS model was created in all rabbits, and CSF CK-BB activity was measured above and below the stenosis level. The electrophysiologic evaluation and the histopathologic examination of the conus medullaris were also performed in each rabbit.

RESULTS

The CK-BB activity was 71.5% in CSF samples that were obtained below the stenosis. The activity was 44.5% in samples obtained above the stenosis and 43.6% in nonstenotic rabbits. In the electrophysiologic studies, the mean amplitudes were decreased and the latency values were lengthened in all ascending and descending nerve potentials at both sides of the stenosis. The number of the neural cells was decreased and imperception of the nucleolus of neural cells and vacuolar degeneration were observed in the histopathologic examination of conus medullaris.

CONCLUSIONS

The activity of CK-BB isoenzyme was increased in CSF of which the circulation was disturbed as a result of neural ischemia, which was accepted in the pathophysiology of LSS.

Relative quantification of proteins in human cerebrospinal fluids by MS/MS using 6-plex isobaric tags

A new 6-plex isobaric mass tagging technology is presented, and proof of principle studies are carried out using standard protein mixtures and human cerebrospinal fluid (CSF) samples. The Tandem Mass Tags (TMT) comprise a set of structurally identical tags which label peptides on free amino-terminus and epsilon-amino functions of lysine residues. During MS/MS fragmentation, quantification information is obtained through the losses of the reporter ions. After evaluation of the relative quantification with the 6-plex version of the TMT on a model protein mixture at various concentrations, the quantification of proteins in CSF samples was performed using shotgun methods. Human postmortem (PM) CSF was taken as a model of massive brain injury and comparison was carried out with antemortem (AM) CSF. After immunoaffinity depletion, triplicates of AM and PM CSF pooled samples were reduced, alkylated, digested by trypsin, and labeled, respectively, with the six isobaric variants of the TMT (with reporter ions from m/z = 126.1 to 131.1 Th). The samples were pooled and fractionated by SCX chromatography. After RP-LC separation, peptides were identified and quantified by MS/MS analysis with MALDI TOF/TOF and ESI-Q-TOF. The concentration of 78 identified proteins was shown to be clearly increased in PM CSF samples compared to AM. Some of these proteins, like GFAP, protein S100B, and PARK7, have been previously described as brain damage biomarkers, supporting the PM CSF as a valid model of brain insult. ELISA for these proteins confirmed their elevated concentration in PM CSF. This work demonstrates the validity and robustness of the tandem mass tag (TMT) approach for quantitative MS-based proteomics.

Reliability of S100B in predicting severity of central nervous system injury

S100B is a protein biomarker that reflects CNS injury. It can be measured in the CSF or serum with readily available immunoassay kits. The excellent sensitivity of S100B has enabled it to confirm the existence of subtle brain injury in patients with mild head trauma, strokes, and after successful resuscitation from cardiopulmonary arrest. The extent of S100B elevation has been found to be useful in predicting clinical outcome after brain injury. Elevations of S100B above certain threshold levels might be able to reliably predict brain death or mortality. A normal S100B level reliably predicts the absence of significant CNS injury. The specificity of S100B levels as a reflection of CNS injury is compromised by the findings that extra-cranial injuries can lead to elevations in the absence of brain injury. This potential problem can most likely be avoided by measuring serial S100B levels along with other biomarkers and carefully noting peripheral injuries. Serum markers GFAP and NSE are both more specific for CNS injury and have little to no extra-cranial sources. Sustained elevations of S100B over 24 h along with elevations of GFAP and NSE can more reliably predict the extent of brain injury and clinical outcomes. In the future, S100B measurements might reliably predict secondary brain injury and enable physicians to initiate therapeutic interventions in a timelier manner. S100B levels have been shown to rise hours to days before changes in ICP, neurological examinations, and neuroimaging tests. S100B levels may also be used to monitor the efficacy of treatments.

Head injury outcome prediction: a role for protein S-100B?

INTRODUCTION

Prediction of the likely outcome of head injury from the outset would allow early rehabilitation to be targeted at those with most to gain. Clinical evaluation of a head injured patient may be confounded by intoxicants such as alcohol. Imaging modalities are insensitive (CT) or impractical (MR) for screening populations of such patients. A peripheral marker that reflected the extent of brain injury might offer an objective indication of likely adverse sequelae. This review evaluates the evidence for Protein S-100B as such a marker.

METHODS

A search of published literature revealed 18 studies designed to evaluate the relation between serum S-100B and measures of outcome after head injury.

RESULTS

A cut-off point of 2.5microg/L is related to dependent disability in those presenting with low conscious level, and may be a specific test for this. There appears to be a relation between initial serum S-100B concentration and measures of disability as well as post-concussion symptoms for those with seemingly mild injuries. There does not appear to be a relation between S-100B and measures of neuropsychological performance.

CONCLUSION

Patients with high levels of S-100B at initial assessment (>2.5microg/L) may represent a high risk group for disability after head trauma.

Serologic markers of brain injury and cognitive function after cardiopulmonary bypass

OBJECTIVE

To examine the association between biochemical markers of brain injury (MBI) and the inflammatory response in relation to neurocognitive deficiency (NCD) after cardiopulmonary bypass (CPB).

SUMMARY BACKGROUND DATA

In cardiac surgery, NCD is a common but underdiagnosed complication with an unclear pathophysiology leading to significant morbidity. Despite extensive investigation, identification of a MBI for clinical use and clarifying the pathophysiology of NCD have not been achieved.

METHODS

Forty patients undergoing CABG and/or valve procedures using CPB were administered a validated neurocognitive battery preoperatively and postoperatively at day 4 and 3 months. S-100b, neuron specific enolase (NSE), and tau protein were assayed as MBIs preoperatively and postoperatively at 6 hours and day 4. C-reactive protein (CRP), interleukin (IL)-6, C3a, and total peroxide levels were also quantified from serum. Impact of cardiotomy suction and antifibrinolytics on markers of brain injury was assessed.

RESULTS

The incidence of early NCD was 40% (16 of 40). NSE and tau protein at the 6-hour time point were both significantly elevated in the presence of NCD (NCD group) compared with those without NCD (NORM group) (8.69 +/- 0.82 vs. 5.98 +/- 0.61; P = 0.018 and 68.8 vs. 29.2%; P = 0.015; respectively). S-100b increase was not different between the NCD and NORM groups. Cardiotomy suction significantly elevated S-100b levels, whereas NSE and tau were not significantly influenced. Aprotinin did not have an effect on NCD or levels of MBIs. Also, the NCD group had significantly elevated CRP and peroxide levels compared with the NORM group at postoperative day 4 while C3a was significantly elevated at 6 hours.

CONCLUSION

NSE and tau are better associated with NCD and less influenced by cardiotomy suction compared with S-100beta. Inflammatory and oxidative stress is associated with NCD post-CPB.

Bench to bedside: evidence for brain injury after concussion--looking beyond the computed tomography scan

The emergency management of cerebral concussion typically centers on the decision to perform a head computed tomography (CT) scan, which only rarely detects hemorrhagic lesions requiring neurosurgery. The absence of hemorrhage on CT scan often is equated with a lack of brain injury. However, observational studies revealing poor long-term cognitive outcome after concussion suggest that brain injury may be present despite a normal CT scan. To explore this idea further, the authors reviewed the evidence for objective neurologic injury in humans after concussion, with particular emphasis on those with a normal brain CT. This evidence comes from studies involving brain tissue pathology, CT scanning, magnetic resonance image (MRI) scanning, serum biomarkers, formal cognitive and balance tests, functional MRI, positron emission tomography, and single-photon emission computed tomography scanning. Each section is accompanied by technical information to help the reader understand what these tests are, not to endorse their use clinically. The authors discuss the strengths and weaknesses of the evidence in each case. These reports make a compelling case for the existence of concussion as a clinically relevant disease with demonstrable neurologic pathology. Areas for future emergency medicine research are suggested.

Glial fibrillary acidic protein in serum after traumatic brain injury and multiple trauma

BACKGROUND

This study aimed to determine whether glial fibrillary acidic protein (GFAP) is released after traumatic brain injury (TBI), whether GFAP is related to brain injury severity and outcome after TBI, and whether GFAP is released after multiple trauma without TBI.

METHODS

This prospective study enrolled 114 patients who had TBI with or without multiple trauma (n = 101) or multiple trauma without TBI (n = 13), as verified by computerized tomography. Daily GFAP measurement began at admission (<12 hours after trauma) and continued for the duration of intensive care (1-22 days). Documentation included categorization of computerized tomography according to Marshall classification, based on daily highest intracranial pressure (ICP), lowest cerebral perfusion pressure (CPP), lowest mean arterial pressure (MAP), and 3-month Glasgow Outcome Score (GOS).

RESULTS

The GFAP concentration was lower for diffuse injury 2 than for diffuse injury 4 (p < 0.0005) or nonevacuated mass lesions larger than than 25 mL (p < 0.005), lower for a ICP less than 25 mm Hg than for a ICP of 25 mm Hg or more, lower for a CPP of 60 mm Hg or more than for a CPP of 60 mm Hg or less, lower for a MAP of 60 mm Hg or more than for a MAP less than 60 mm Hg (all p < 0.0005), and lower for a GOS of 1 or 2 than for a GOS of 3, 4 (p < 0.05), or 5 (p < 0.0005). After TBI, GFAP was higher in nonsurvivors (n = 39) than in survivors (n = 62) (p < 0.005). After multiple trauma without TBI, GFAP remained normal.

CONCLUSIONS

The findings showed that GFAP is released after TBI, that GFAP is related to brain injury severity and outcome after TBI, and that GFAP is not released after multiple trauma without brain injury.

Serum S 100 B: a marker of brain damage in traumatic brain injury with and without multiple trauma

This prospective clinical study was conducted to determine whether S 100 B is a reliable serum marker for traumatic brain injury (TBI) with and without multiple trauma. Fifty-five trauma patients (Injury Severity Score [ISS] > or = 24 and Glasgow Coma Score [GCS] < or = 8) were classified by radiography, computer tomography, ultrasound, and neurology as TBI without multiple trauma (n = 23), TBI with multiple trauma (n = 23), or multiple trauma without TBI (n = 9). S 100 B was measured initially after trauma and daily for a maximum of 21 days. Both survivors and nonsurvivors had markedly increased S 100 B initially. All survivors returned to normal or moderately increased S 100 B levels within the first 48 h after trauma. In contrast, all nonsurvivors of isolated TBI had S 100 B values that either increased consistently or dropped and then increased again 48 h after the initial increase after trauma. There was no relationship between localization, extent, or severity of TBI and S 100 B. According to receiver operating characteristic curve analysis and calculation of the area under the curve (AUC), S 100 B is equally accurate for mortality prediction at 24, 48, and 72 h after trauma and is most accurate >84 h after trauma. Sensitivity/specificity for mortality prediction are more accurate in TBI without multiple trauma (AUC 0.802-0.971) than in TBI with multiple trauma (AUC 0.693-0.783). Thus, though S 100 B may be a reliable marker of brain damage in TBI without multiple trauma 24 h after trauma and thereafter, it appears to be less reliable in TBI with multiple trauma.

Serum S-100B protein in severe head injury

OBJECTIVE

Despite the significant recent progress in cerebral monitoring, it is still difficult to quantify the extent of primary brain injury and ongoing secondary damage after head injury. The objective of our study was to investigate S-100B protein as a serum marker of brain damage after severe head injury.

METHODS

Eighty-four patients with severe head injury (Glasgow Coma Scale score < or =8) were included in this prospective study. Venous blood samples for S-100B protein were obtained as soon as possible after admission and every 24 hours thereafter, for a maximum of 10 consecutive days. Serum levels of S-100B protein were compared with outcome after 6 months, clinical variables, and the category of the Marshall classification of initial computed tomographic findings.

RESULTS

Patients who died had significantly higher serum S-100B values compared with those who survived (median, 2.7 microg/L versus 0.54 microg/L; P < 0.0001, Mann-Whitney U test). Nineteen (58%) of 33 patients who died had peak S-100B values of 2 microg/L or higher, compared with 4 (8%) of the 51 surviving patients (P < 0.0005, Fisher's exact test). There was also a strong correlation between S-100B values and computed tomographic findings. Logistic regression analysis in a model with age, Glasgow Coma Scale score, intracranial pressure, and computed tomographic findings revealed S-100B as an independent predictor of outcome. Persistent elevation of S-100B levels for 2 to 6 days, even in patients with favorable outcome, may reflect ongoing secondary damage after severe head injury.

CONCLUSION

S-100B may be a promising serum marker for assessing the extent of primary injury and the time course of secondary damage after severe head injury.

Traumatic brain damage in minor head injury: relation of serum S-100 protein measurements to magnetic resonance imaging and neurobehavioral outcome

OBJECTIVE

The present study was conducted to validate S-100 protein as a marker of brain damage after minor head injury.

METHODS

We studied 50 patients with minor head injuries and Glasgow Coma Scale scores of 13 to 15 in whom computed tomographic scans of the brain revealed no abnormalities. Serum levels of S-100 protein were measured at admittance and hourly thereafter until 12 hours after injury. Magnetic resonance imaging and baseline neuropsychological examinations were performed within 48 hours, and neuropsychological follow-up was conducted at 3 months postinjury.

RESULTS

Fourteen patients (28%) had detectable serum levels of S-100 protein (mean peak value, 0.4 microg/L [standard deviation, +/- 0.3]). The S-100 protein levels were highest immediately after the trauma, and they declined each hour thereafter. At 6 hours postinjury, the serum level was below the detection limit (0.2 microg/L) in five (36%) of the patients with initially detectable levels. Magnetic resonance imaging revealed brain contusions in five patients, four of whom demonstrated detectable levels of S-100 protein in serum. The proportion of patients with detectable serum levels was significantly higher when magnetic resonance imaging revealed a brain contusion. In patients with detectable serum levels, we observed a trend toward impaired neuropsychological functioning on measures of attention, memory, and information processing speed.

CONCLUSION

Determination of S-100 protein levels in serum provides a valid measure of the presence and severity of traumatic brain damage if performed within the first hours after minor head injury.

The Glasgow Coma Scale: a critical appraisal of its clinimetric properties

The Glasgow Coma Scale is a commonly used instrument in clinical practice. This article examines the published evidence to assess whether the scale possesses the requisite clinimetric properties. Articles describing and using the scale were located through a MEDLINE search. The clinimetric properties of the scale were appraised using the methodological principles of sensibility, reliability, validity, and responsiveness. The scale has a good sensibility and reliability (intraclass correlation coefficient, 0.8 to 1 for trained users). It has a well-established cross-sectional construct validity. Its predictive validity in traumatic coma, when combined with age and brainstem reflexes, is good in the generating sample (sensitivity, 79 to 97%; specificity, 84-97%) but has not been tested in an external validation sample. Its longitudinal construct validity has not been studied adequately. Thus, the scale is an established discriminative instrument but its validity as a predictive and an evaluative instrument has not yet been studied adequately.

Increased creatine kinase brain isoenzyme concentration in cerebrospinal fluid with meningitis

CPK-BB (CK-BB) isoenzyme is an intracellular enzyme released in various neurologic conditions, including central nervous system (CNS) infections. Activity of CK-BB in cerebrospinal fluid (CSF) was determined in 80 children by electrophoresis and densitometry. The possible correlation between CNS infection and CK concentrations was assessed. Significantly elevated concentrations of CK activity (P < 0.01) in the CSF were found in children with bacterial meningitis as compared with children with either aseptic meningitis or normal CSF findings. The data suggest the possibility of utilizing CSF CK activity to differentiate between bacterial and viral meningitis in situations where a routine CSF examination is inconclusive.

Serum S100 protein: a potential marker for cerebral events during cardiopulmonary bypass

BACKGROUND

There is no simple method to determine the incidence or severity of brain injury after a cardiac operation. A serum marker equivalent to cardiac enzymes is required. S100 protein leaks from the cerebrospinal fluid to blood after cerebral injury. We sought to determine the pattern of release after extracorporeal circulation (ECC).

METHODS

Thirty-four patients without neurologic problems underwent coronary bypass using ECC. Four had carotid stenoses. Nine others underwent coronary bypass without ECC. Serum S100 levels were measured before, during, and after the operation.

RESULTS

S100 was not detected before sternotomy. Postoperative levels of S100 were related to duration of perfusion (r = 0.89, p < 0.001). Patients who did not have ECC had undetectable or fractionally raised levels except in 1 who suffered a stroke. No patient in whom ECC was used suffered an event, but those with carotid stenosis had greater S100 levels.

CONCLUSIONS

S100 protein leaks into blood during ECC and may reflect both cerebral injury and increased permeability of the blood brain barrier. S100 is a promising marker for cerebral injury in cardiac surgery if elevated levels can be linked with clinical outcome.

Markers of cerebral ischemia after cardiac surgery

The objective of this review is to provide an overview of the use of biochemical markers for the detection of Central Nervous System (CNS) complications after cardiac surgery and extracorporeal circulation (ECC). A computerized literature search in MEDLINE from 1966 onward was the basis for the references. The literature covering the following biochemical markers is reviewed: adenylkinase, creatine phosphokinase isoenzyme BB (CK-BB), lactate, neuron-specific enolase (NSE), S-100 protein, myelin basic protein, lactate dehydrogenase, aspartate aminotransferase, glutathione, vasointestinal neuropeptide, and 7B2-specific neuropeptide. For clinical purposes, it is necessary to have a biochemical marker that can be measured in blood. Lactate, although a primary marker of anaerobic metabolism, and CK-BB values, calculated from the arterio-internal jugular venous difference, appear to correlate with periods of ischemia during ECC. S-100 protein levels have been shown to correlate with duration of ECC, and when combined with NSE values, could be used to identify patients with CNS dysfunction after cardiac surgery. The use of NSE may be limited by its presence in erythrocytes and platelets because the high levels that can result from hemolysis can render it less specific. Although recently introduced, S-100 protein may have the potential to be a valuable marker for CNS dysfunction after ECC.

Increased serum creatine kinase BB and neuron specific enolase following head injury indicates brain damage

The aim of this study was to examine whether an increase in the serum concentrations of the two brain enzymes creatine kinase BB (CK-BB) and neuron specific enolase (NSE) can be demonstrated in patients with acute head injury and whether such an increase reflects release from damaged brain tissue. In 60 patients who had suffered minor to severe head injury, serial blood samples were drawn during the first hours after impact, and CK-BB and NSE were measured by radioimmunoassay. Computed tomography (CT) was also performed shortly after admission to hospital, and was repeated 1-3 days later in selected patients. Increased serum concentrations of both CK-BB and NSE were found in 88% of the patients with moderate to severe head injury (group 1, n = 18) and in 23% of the patients with minor head injury (group 2, n = 42), whereas CT showed contusion in only 41% and 2% of the group 1 and 2 patients, respectively. The following findings suggest that the enzymes had been released from brain tissue: 1) The maximum concentrations of CK-BB and NSE correlated with the severity of injury as assessed clinically and with the volume of contusion as estimated from CT (r = 0.79 with CK-BB, r = 0.72 with NSE). 2) The maximum concentrations of CK-BB and NSE were closely correlated (r = 0.87).(ABSTRACT TRUNCATED AT 250 WORDS)

Efficacy of cerebro-spinal fluid biochemistry in the diagnosis of brain insult

Postmortem biochemical indices may provide a useful adjunct to morphological studies in the identification of antemortem brain insult. We studied 34 routine medico-legal cases categorising them into one of four diagnostic groups. There were 11 cases of head trauma, 7 of 'hypoxia' (3 hangings and 4 carbon monoxide or drug poisonings), 7 sudden cardiac deaths and 9 miscellaneous cases. Survival time and postmortem interval was known for each case. The degree of cranio-cerebral trauma was graded. Cerebro-spinal fluid (CSF) and vitreous humour were analysed for calcium, glucose, total proteins, aldolase, aspartate transaminase (AST), alanine transaminase (ALT), gamma glutamyltransferase (GGT), lactate dehydrogenase (LDH), creatine kinase (CK) and creatine kinase BB isoenzyme (CK-BB). CK-BB was also measured in superior vena cava serum. In CSF there was a significant correlation between the severity of cranio-cerebral trauma and levels of aldolase, CK-BB, AST, ALT and total proteins. CSF CK-BB, median units/l (range), for the groupings of head trauma, hypoxia, sudden cardiac death and miscellaneous were respectively 823 (2-3431); 96 (2-187); 4 (2-25); 5 (1-69). Corresponding serum CK-BB levels were 240 (28-322); 390 (26-411); 180 (20-482); 79 (18-530).

Serum aldolase isozyme levels in patients with cerebrovascular diseases

A subunit specific radioimmunoassay was developed for the quantification of human aldolase A, B, and C. The method used was a double antibody radioimmunoassay using radioiodinated purified aldolase A, B, or C subunits as the ligand, specific chicken antibodies to aldolase isozymes and rabbit antibodies to chicken IgG. The Iodogen method was used for iodination of the purified isozyme subunits in this study. Human brain tissue contained similar concentrations of aldolase A and aldolase C, and a smaller amount of aldolase B, which was the main isozyme of liver tissue. Levels of serum aldolase A were greater than 203 ng/ml, the upper limit of normal, in six of 24 patients with cerebral infarction and in 11 of 31 patients with cerebral hemorrhage. Nine of 24 patients with cerebral infarction and 16 of 31 patients with cerebral hemorrhage had serum aldolase C levels greater than 4.1 ng/ml, the upper limit in normal sera. These data suggest that serum aldolase C may be a more specific and sensitive marker of cerebrovascular diseases than aldolase A. We also demonstrated that serial measurement of serum aldolase C in patients with cerebrovascular diseases might be useful in estimating prognosis, since serially increasing serum aldolase C levels during the course of these diseases were correlated with a high mortality rate.

Creatine-kinase-BB after severe head-injury as an index of prognosis in relation to nature of trauma and patients age

Creatine-Kinase-BB (CK-BB) is a brain specific enzyme, with a prognostic value for the patient's outcome after head-injury. We have investigated 76 brain injured patients and attempted to show a correlation of the concentrations of CK-BB and the Glasgow-Outcome-Scale (GOS). Patients with a CK-BB concentration of more than 50 ng/ml died. Patients, who had a CK-BB concentration less than 25 ng/ml showed only minimal neurological deficits. Intracerebral contusions and acute subdural haematomas showed the highest CK-BB concentration, indicating a high degree of braintissue-damage. CK-BB seems to have no correlation with the age of patients. Normalisation of elevated CK-BB levels do not correlate with recovery from neurological deficit.

Relationship between CT attenuation changes and post-traumatic CSF-CKBB-activity after severe head injury in man

In order to evaluate if it is practically possible to assess the volume of contused brain tissue from the CT pictures, a comparison has been carried out between the size of the cerebral contusion(s)--as estimated from the CT scans--and the post-traumatic CSF-CKBB activity, in a series of 29 patients with severe head injury. A clearance curve for the elimination of CKBB from the CSF was constructed. The relation between contusion volume and CSF-CKBB-activity was not statistically significant, while the relationships between contusion volume and outcome, and between CSF-CKBB, as estimated at 6 hours after from the clearance curve, and outcome, were.

Improved outcome prediction based on CSF extrapolated creatine kinase BB isoenzyme activity and other risk factors in severe head injury

The present study of 43 patients with severe head injury shows that outcome prediction can be markedly improved by combining an appropriate marker of the degree of initial brain damage and other risk factors. The patients were classified into three groups according to their actual outcome after 6 months: death (22 patients); persistent vegetative state or severe disability (eight patients); and moderate disability or good recovery (13 patients). By applying stepwise logistic discriminant analysis to the patients' data, five significant risk factors were selected: degree of neurological damage assessed by cerebrospinal fluid (CSF) extrapolated creatine kinase BB isoenzyme activity, Glasgow-Liège Coma Scale score, age, incidence of thoracic injury, and intracranial pressure (ICP). Extrapolated creatine kinase BB activity had the highest prognostic ability (67%). Uncontrollable elevated ICP proved to be systematically associated with death, whereas its absence was not necessarily indicative of a favorable outcome. The combination of the five variables yielded a total prognostic efficiency of 91%. The percentages of correctly predicted patients for the three outcome groups were, respectively, 100%, 50%, and 100%. Thus, half of the persistently vegetative and severely disabled patients were identified by the selected factors.