Effect of senescence on the tyrosine hydroxylase and S100B immunoreactivity in the nigrostriatal pathway of the rat.

Senescence is a natural and progressive physiological event that leads to a series of morphophysiological alterations in the organism. The brain is the most vulnerable organ to both structural and functional changes during this process. Dopamine is a key neurotransmitter for the proper functioning of the brain, directly involved in circuitries related with emotions, learning, motivation and reward. One of the main dopamine- producing nuclei is the substantia nigra pars compacta (SNpc), which establish connections with the striatum forming the so-called nigrostriatal pathway. S100B is a calcium binding protein mainly expressed by astrocytes, involved in both intracellular and extracellular processes, and whose expression is increased following injury in the nervous tissue, being a useful marker in altered status of central nervous system. The present study aimed to analyze the impact of senescence on the cells immunoreactive for tyrosine hydroxylase (TH) and S100B along the nigrostriatal pathway of the rat. Our results show an decreased expression of S100B+ cells in SNpc. In addition, there was a significant decrease in TH immunoreactivity in both projection fibers and TH+ cell bodies. In the striatum, a decrease in TH immunoreactivity was also observed, as well as an enlargement of the white matter bundles. Our findings point out that senescence is related to the anatomical and neurochemical changes observed throughout the nigrostriatal pathway.

Lutein levels in arterial cord blood correlate with neurotrophic calcium binding S100B protein in healthy preterm and term newborns.

BACKGROUND: S100B is an established biomarker of brain development and damage. Lutein (LT) is a naturally occurring xanthophyll carotenoid mainly concentrated in the central nervous system (CNS), but its neurotrophic role is still debated. We investigated whether LT cord blood concentrations correlate with S100B in a cohort of preterm and term healthy newborns. METHODS: We conducted a prospective study on the distribution of LT and S100B in arterial cord blood of healthy preterm (n = 50) and term (n = 50) newborns. RESULTS: S100B and LT showed a pattern of concentration characterized by higher levels (P < 0.01, for all) at 33-36 weeks gestation (GA) followed by a progressive decrease (P < 0.01, for all) from 37 onwards with a dip at term. Both S100B and LT were gender-dependent with significantly (P < 0.01, for all) higher levels in females in preterm and term groups. S100B (R = 0.68; P < 0.001) and LT (R = 0.40; P = 0.005) correlated with GA at sampling. A positive significant correlation (R = 0.87; P < 0.001) between S100B and LT was found. CONCLUSIONS: The present data showing a correlation between S100B and LT supports the notion of a LT trophic role in the CNS. Further investigations in high-risk infants are needed to elucidate LT involvement in the pathophysiological cascade of events leading to CNS development and damage.

The Value of the Biomarkers Neuron-Specific Enolase and S100 Calcium-Binding Protein for Prediction of Mortality in Children Resuscitated After Cardiac Arrest.

The aim of the present study was to assess the ability of the biomarkers neuron-specific enolase (NSE) and S100 calcium-binding protein b (S100b) to predict 30 day mortality in children resuscitated from cardiac arrest (CA). It was a prospective observational study at a single tertiary heart centre. Consecutive children were admitted after resuscitated in-hospital and out-of-hospital CA. Levels of NSE and S100b were analyzed from 12 to 24 hours, from 24 to 48 hours, and from 48 to 72 hours after admission. The primary endpoint was 30-day mortality. Differences in biomarker levels between survivors and non-survivors were analyzed with the Mann-Whitney U test. Receiver operating characteristics (ROC) curves were applied to assess the predictive ability of the biomarkers and the areas under the ROC curves (AUC) were presented. A total of 32 resuscitated CA patients were included, and 12 (38%) patients died within 30 days after resuscitation. We observed significantly higher levels of NSE and S100b in non-survivors compared to survivors at all timepoints from 12 to 72 hours after CA. NSE achieved AUCs from 0.91-0.98 for prediction of 30 day mortality, whereas S100b achieved AUCs from 0.93-0.94. An NSE cut-off of 61 µg/L sampled between 12-24 hours from admission achieved a sensitivity of 80% and a specificity of 100% for prediction of 30 day mortality. In children resuscitated from CA, the biomarkers NSE and S100b appear to be solid predictors of mortality after 30 days.

TBISTAT: An open-source, wireless portable, electrochemical impedance spectroscopy capable potentiostat for the point-of-care detection of S100B in plasma samples.

Point-of-Care (POC) testing for biomarker detection demands techniques that are easy to use, readily available, low-cost, and with rapid response times. This paper describes the development of a fully open-source, modular, wireless, battery-powered, smartphone-controlled, low-cost potentiostat capable of conducting electrochemical impedance spectroscopy for the electrochemical detection of the S100B protein captured in an ANTI-S100B functionalized thin-film gold interdigitated electrode platform to support traumatic brain injury diagnosis and treatment. EIS results from the developed potentiostat were validated with a commercial benchtop potentiostat by comparing impedance magnitude and phase values along the EIS frequency range. In addition, an experimental design was performed for detecting S100B in spiked human plasma samples with S100B concentrations of clinical utility, and a calibration curve was found for quantifying S100B detection. No statistically significant differences were found between EIS results from the developed potentiostat and the commercial potentiostat. Statistically significant differences in the changes in charge transfer resistance signal between each tested S100B concentration (p < 0.05) were found, with a limit of detection of 35.73 pg/mL. The modularity of the proposed potentiostat allows easier component changes according to the application demands in power, frequency excitation ranges, wireless communication protocol, signal amplification and transduction, precision, and sampling frequency of ADC, among others, when compared to state-of-the-art open-source EIS potentiostats. In addition, the use of minimal, easy acquirable open-source hardware and software, high-level filtering, accurate ADC, Fast Fourier Transform with low spectral leakage, wireless communication, and the simple user interface provides a framework for facilitating EIS analysis and developing new affordable instrumentation for POC biosensors integrated systems.

S100B in maternal circulation of pregnancies complicated by FGR and brain sparing.

OBJECTIVE: To determine whether the presence of brain sparing in fetal growth restricted (FGR) fetuses involves elevation of the cerebral injury biomarker S100B in maternal circulation. METHODS: We included 63 women with suspected small for gestational age (SGA) fetuses between 24 and 35 +6/7 weeks of gestation. Maternal plasma angiogenic factors measurements and sonographic evaluation were performed at recruitment. Next, we subdivided our SGA cohort into three groups: SGA fetuses, FGR fetuses without brain-sparing, and FGR fetuses with brain-sparing (FGR-BS). Serum S100B concentration was calculated as S100B µg/L, S100B MoM, and the ratio S100B/ estimated fetal weight (EFW). We also report one case of S100B concentration surge in maternal serum following the diagnosis of fetal intraventricular hemorrhage (IVH). RESULTS: The FGR-BS group had higher maternal S100B µg/L (p < 0.01, p < 0.05, respectively), S100B MoM (p < 0.001, p < 0.001, respectively), and S100B/EFW (p < 0.001, p < 0.01, respectively), compared to the SGA and FGR groups. In the case report, maternal serum S100B concentrations were 0.0346 µg/L before, and 0.0874 µg/L after IVH occurrence. CONCLUSIONS: S100B concentration in maternal serum increased in pregnancies complicated by FGR and brain sparing. These results may substantiate in-utero cerebral injury and may explain the adverse neurocognitive outcomes reported for this group.

Usability of the Level of the S100B Protein, the Gosling Pulsatility Index, and the Jugular Venous Oxygen Saturation for the Prediction of Mortality and Morbidity in Patients with Severe Traumatic Brain Injury.

The high frequency of traumatic brain injury imposes severe economic stress on health and insurance services. The objective of this study was to analyze the association between the serum S100B protein, the Gosling pulsatility index (PI), and the level of oxygen saturation at the tip of the internal jugular vein (SjVO2%) in patients diagnosed with severe TBI. The severity of TBI was assessed by a GCS score ≤ 8 stratified by Glasgow outcome scale (GOS) measured on the day of discharge from the hospital. Two groups were included: GOS < 4 (unfavorable group (UG)) and GOS ≥ 4 (favorable group (UG)). S100B levels were higher in the UG than in the FG. PI levels in the UG were also substantially higher than in the FG. There were similar levels of SjVO2 in the two groups. This study confirmed that serum S100B levels were higher in patients with unfavorable outcomes than in those with favorable outcomes. Moreover, a clear demarcation in PI between unfavorable and FGs was observed. This report shows that mortality and morbidity rates in patients with traumatic brain injury can be assessed within the first 4 days of hospitalization using the S100B protein, PI values, and SjVO2.

New insights into the role and origin of pituitary S100ß-positive cells.

In the anterior pituitary, S100ß protein (S100ß) has been assumed to be a marker of folliculo-stellate cells, which are one of the non-hormone-producing cells existing in the parenchyma of the adult anterior lobe and are composed of subpopulations with various functions. However, recent accumulating studies on S100ß-positive cells, including non-folliculo-stellate cells lining the marginal cell layer (MCL), have shown the novel aspect that most S100ß-positive cells in the MCL and parenchyma of the adult anterior lobe are positive for sex determining region Y-box 2 (SOX2), a marker of pituitary stem/progenitor cells. From the viewpoint of SOX2-positive cells, the majority of these cells in the MCL and in the parenchyma are positive for S100ß, suggesting that S100ß plays a role in the large population of stem/progenitor cells in the anterior lobe of the adult pituitary. Reportedly, S100ß/SOX2-double positive cells are able to differentiate into hormone-producing cells and various types of non-hormone-producing cells. Intriguingly, it has been demonstrated that extra-pituitary lineage cells invade the pituitary gland during prenatal pituitary organogenesis. Among them, two S100ß-positive populations have been identified: one is SOX2-positive population which invades at the late embryonic period through the pituitary stalk and another is a SOX2-negative population that invades at the middle embryonic period through Atwell's recess. These two populations are likely the substantive origin of S100ß-positive cells in the postnatal anterior pituitary, while S100ß-positive cells emerging from oral ectoderm-derived cells remain unclear.

S100B protein level for the detection of clinically significant intracranial haemorrhage in patients with mild traumatic brain injury: a subanalysis of a prospective cohort study.

BACKGROUND: Clinical assessment of patients with mild traumatic brain injury (mTBI) is challenging and overuse of head CT in the ED is a major problem. Several studies have attempted to reduce unnecessary head CTs following a mTBI by identifying new tools aiming to predict intracranial bleeding. Higher levels of S100B protein have been associated with intracranial haemorrhage following a mTBI in previous literature. The main objective of this study is to assess whether plasma S100B protein level is associated with clinically significant brain injury and could be used to reduce the number of head CT post-mTBI. METHODS: Study design: secondary analysis of a prospective multicentre cohort study conducted between 2013 and 2016 in five Canadian EDs. Inclusion criteria: non-hospitalised patients with mTBI with a GCS score of 13-15 in the ED and a blood sample drawn within 24 hours after the injury. Data collected: sociodemographic and clinical data were collected in the ED. S100B protein was analysed using ELISA. All CT scans were reviewed by a radiologist blinded to the biomarker results. Main outcome: the presence of clinically important brain injury. RESULTS: 476 patients were included. Mean age was 41±18 years old and 150 (31.5%) were women. Twenty-four (5.0%) patients had a clinically significant intracranial haemorrhage. Thirteen patients (2.7%) presented a non-clinically significant brain injury. A total of 37 (7.8%) brain injured patients were included in our study. S100B median value (Q1-Q3) was: 0.043 µg/L (0.008-0.080) for patients with clinically important brain injury versus 0.039 µg/L (0.023-0.059) for patients without clinically important brain injury. Sensitivity and specificity of the S100B protein level, if used alone to detect clinically important brain injury, were 16.7% (95% CI 4.7% to 37.4%) and 88.5% (95% CI 85.2% to 91.3%), respectively. CONCLUSION: Plasma S100B protein level was not associated with clinically significant intracranial lesion in patients with mTBI.

Neuroinflammatory Biomarkers Associated With Mild Traumatic Brain Injury History in Special Operations Forces Combat Soldiers.

BACKGROUND: Special Operations Forces (SOF) combat soldiers are frequently exposed to blast and blunt neurotrauma, most often classified as mild traumatic brain injury (mTBI). Repetitive mTBI may increase the risk of developing long-term neurological sequelae. Identifying changes in neuroinflammatory biomarkers before chronic conditions emerge could serve as preliminary evidence of developing neuropathology. OBJECTIVE: To determine the effects of mTBI history, lifetime mTBI incidence, and recency on blood biomarker concentrations of axonal protein neurofilament light (NfL), glycolytic enzyme neuron-specific enolase (NSE), astrocyte-expressed S100 calcium-binding protein B (S100B), and neurotrophic cytokine interleukin-6 (IL-6) in healthy, active duty SOF combat soldiers. METHODS: Self-reported mTBI history/recency and fasted blood samples were collected in this cross-sectional study of 104 asymptomatic SOF combat soldiers. Biomarker concentrations were quantified using commercial enzyme-linked immunosorbent assays. Mann-Whitney U and Kruskal-Wallis tests were used to compare groups. Post hoc tests with appropriate corrections were conducted as warranted. RESULTS: Soldiers with mTBI history had higher NSE concentrations than those without (z = -2.60, P = .01). We also observed significant main effects of lifetime mTBI incidence on NSE (χ(3) = 9.52, P = .02) and S100B (χ(3) = 8.21, P = .04) concentrations and a significant main effect of mTBI recency on NfL concentration (χ(2) = 6.02, P = .049). CONCLUSION: The SOF combat soldiers with mTBI history had increased NSE. Longitudinal studies in this population are needed due to between-subject heterogeneity in biomarker concentrations. The NfL concentrations in our SOF combat soldiers-regardless of mTBI history or recency-were similar to values previously reported in civilian acute TBI patients.

Association of S100B 3'UTR polymorphism with risk of chronic heart failure in a Chinese Han population.

To study the correlation between single nucleotide polymorphism (SNP) of the 3' untranslated region (UTR) rs9722 locus in S100B and the risk of chronic heart failure (CHF), plasma levels of S100B protein as well as has-miR-340-3p in a Chinese Han population.A total of 215 patients with CHF (124 ischemic cardiomyopathy (ICM) and 91 dilated cardiomyopathy (DCM)) and 215 healthy controls were recruited to analyze the S100B rs9722 genotype by Sanger sequencing. The levels of hsa-miR-340-3p in the plasma were detected by RT-PCR, and S100B levels were detected by ELISA.The risk of CHF in S100B rs9722 locus T allele carriers was 4.24 times higher than that in those with the C allele (95% CI: 2.84-6.33, P < .001). The association of S100B rs9722 locus SNP with ICM and DCM risk was not affected by factors such as age, gender, and body mass index (BMI). The levels of plasma S100B and hsa-miR-340-3p in patients with ICM and DCM were significantly higher than those in the control group (P < .001). There was no significant difference in plasma S100B levels between patients with ICM and DCM (P > .05). Among ICM, DCM, and control subjects, TT genotype carriers had the highest levels of plasma S100B and hsa-miR-340-3p, followed by the CT genotype and TT genotype, and the difference was statistically significant (P < .05). Plasma hsa-miR-340-3p levels were positively correlated with S100B levels in the control subjects and patients with ICM and DCM.The S100B rs9722 locus SNP is associated with CHF risk in a Chinese Han population.

S100B outperforms clinical decision rules for the identification of intracranial injury on head CT scan after mild traumatic brain injury.

Objective: To compare the classification accuracy of S100B to two clinical decision rules- Canadian CT Head Rule (CCHR) and New Orleans Criteria (NOC)-for predicting traumatic intracranial injuries (ICI) after mild traumatic brain injury (mild TBI).Methods: A secondary analysis of a prospective observational study of mild TBI patients was performed. The diagnostic performance of S100B for predicting ICI on head CT was compared to both the CHRR and NOC. Area under receiver operator characteristic (AUC) curves were used and multivariable analysis was used to create a new decision rule based on a combination of S100B and decision rule-related variables.Results: S100B had the highest negative predictive value (97.3%), positive predictive value (7.21%), specificity (33.6%) and positive likelihood ratio (1.3), and the lowest negative likelihood ratio (0.5). The proportion of mild TBI subjects with potentially avoidable head CT scans was highest using S100B (37.7%). The addition of S100B to both clinical decision rules significantly increased AUC. A novel decision rule adding S100B to three decision rule-related variables significantly improved prediction (p < 0.05).Conclusion: Serum S100B outperformed clinical decision rules for identifying mild TBI patients with ICI. Incorporating clinical variables with S100B maximized ICI prediction, but requires validation in an independent cohort.

PTSD Susceptibility and Challenges: Pathophysiological Consequences of Behavioral Symptoms.

INTRODUCTION: Posttraumatic stress disorder (PTSD) can develop during the aftermath of traumatic events. Although many are impacted by several stressors, nearly 3.6% suffer from PTSD in the United States with higher incidence reported in military service personnel. Any injury to the blood-brain barrier can ignite an array of biological signaling molecules in the immune-privileged brain parenchyma, which can disrupt the synaptic neural network, resulting in altered behavior. MATERIALS AND METHODS: In this preliminary study, we compared 20 PTSD veterans with age-matched healthy veterans to identify plasma levels of brain-specific protein markers using enzyme-linked immunosorbent assay/immunofluorometric sandwich assay for neurotrophic factors and neuropoietic cytokines, and catalytic activity of matrix metalloproteinase (MMP) by zymography. RESULTS: We observed an increased level of glial fibrillary acidic protein, tumor necrosis factor-alpha, interleukin 6, and MMP2 and MMP9 but decreased level of brain-derived neurotrophic factor, nerve growth factor-beta, and negligible difference in astroglial marker S100 calcium-binding protein B compared to controls. CONCLUSION: Identification of neural biomarkers is essential to understand the subclinical symptoms for the diagnosis PTSD, which may not be visible by magnetic resonance imaging (MRI/fMRI) and may take years to clinically manifest.

Monitoring from Battlefield to Bedside: Serum Repositories Help Identify Biomarkers, Perspectives on Mild Traumatic Brain Injury.

OBJECTIVES: Serum repositories are foundations for seroepidemiological data, revealing targeted information about morbidities and existing heterogeneity in human populations. With the recent technological advances, we can perform high-throughput screening at an affordable cost using minimal plasma. Monitoring brain health after an injury is critical since mild Traumatic Brain Injury (mTBI) and other neurological symptoms are under-diagnosed. Our objective in this study is to present our preliminary serological data from one of our ongoing studies on mTBI. METHODS: In this retrospective study, we used stored plasma samples to understand biomarkers of mTBI. We compared plasma samples from five patients with mTBI following their first concussive episode to five gender and age-matched healthy controls. We assessed multiple biomarkers to show the importance of biorepositories. RESULTS: Most of the estimated plasma factors in mTBI subjects at baseline were comparable to normal healthy individuals except for the astroglial markers S100B and glial fibrillary acidic protein. Fluctuations of these biomarkers can affect the homeostasis of brain parenchyma by altering the neural network signaling, which in turn may result in intermittent behavioral symptoms. CONCLUSION: Biorepositories are powerful resources for understanding the spectrum of morbidity. Biomarkers serve as a valuable diagnostic and therapeutic tool.

S100B as a new fecal biomarker of inflammatory bowel diseases.

OBJECTIVE: S100 proteins are demonstrated to exert a protective role in the gastrointestinal tract. In the present study, we investigated whether S100B protein, that is typically expressed by enteroglial cells, is detectable in feces and could be a useful noninvasive indicator of gut chronic inflammation. PATIENTS AND METHODS: This clinical prospective study included n=48 patients suffering Crohn's disease (CD) or ulcerative colitis (UC) and non IBD-controls. The clinical disease activity was evaluated using Harvey-Bradshaw or Mayo Score Index while the diagnosis of IBD was defined based on standard endoscopic and histological criteria. S100B and calprotectin were extracted and analyzed using commercial enzyme-linked immunosorbent assay (ELISA) kits. RESULTS: Unlike calprotectin, S100B was significantly decreased in both CD and UC compared to non IBD-patients. The strongest quantitative alterations of S100B were detected concomitantly with signs of active or quiescent disease, including high/normal expression of fecal calprotectin, mucosal damage/cryptitis, mucin depletion and inflammatory infiltrate, as defined by endoscopic evaluation and histological analysis. At the onset of disease and under no Infliximab-based therapy, the lowest was detected suggesting that S100B in feces could have a potential diagnostic value for IBD. CONCLUSIONS: Testing for S100B and calprotectin could be a useful screening tool to better predict IBD activity.

The utility of S100B level in detecting mild traumatic brain injury in intoxicated patients.

BACKGROUND: S100B is a serum protein known to elevate in patients with brain injury, but it is unknown whether it can predict intracranial pathology in intoxicated patients following mild traumatic brain injury (MTBI). We performed a systematic review and meta-analysis of the English language literature to address this question. MAIN OUTCOMES AND RESULTS: Four prospective cohort trials of serum S100B levels on acutely intoxicated patients with MTBI were included in this meta-analysis. Prevalence of intracranial pathology in the pooled cohort of the intoxicated MTBI patients was 10%, lower than the 15-30% reported in the literature for the general MTBI population. Standard mean difference of serum S100B levels between patients with and without intracranial pathology on CT was 0.73 µg/L (Z = 18.33, P < 0.001). Following sensitivity analysis and hierarchical summary receiver-operating characteristic models, three remaining articles were used for pooled estimates that found that S100B had a sensitivity of 0.96 (95% CI: 0.84-1.00, I2 = 0%) and specificity of 0.63 (95% CI: 0.58-0.68, I2 = 86.8%) with a high negative predictive value (100%, 95% CI: 95.14-100, I2 = 0%) and a negative LR of 0.06 (95% CI: 0.01-0.31). CONCLUSIONS: Serum S100B levels may have utility in ruling out intracranial pathology in intoxicated patients, however more study and comparison with other serum biomarkers of brain injury are necessary before this becomes the accepted standard of care.

NSE & S100B protein blood level assessment during a long-distance trail race.

The acute and chronic consequences of long-distance running on brain function have received little attention. The impact of such a hard-physical burden associated with sleep privation during such events such has never been explored in terms of neuropsychological function and brain damage. METHODS: Blood samples were collected from 4 athletes before, during and at the end of one of two races: Grand Raid de la Réunion 2017 (GRR: 165 km, elevation gain: 9529 m, 2 runners) and Trail de la Bourbon 2017 (TB: 111 km, elevation gain: 6433 m, 2 runners). Serum S100B and NSE levels were measured for each runner before, during and after the race. RESULTS: Serum S100B levels (normal range: < 0.15 µg/L) increased early during the race and remained high up to the end of the race in all 4 runners (range: 0.17-0.59 µg/L). NSE level (normal range: < 15 µg/L) increased in 3 of the 4 runners (range: 16.8-39.2 µg/L). CONCLUSIONS: This preliminary study shows the potential interest of S100B and NSE serum assessment during long-distance races. Further studies are needed to confirm these results and to investigate the origins and significance of this increase in brain injury markers.

A SERS-based lateral flow assay for the stroke biomarker S100-ß.

A surface-enhanced Raman scattering (SERS)-based lateral flow assay (LFA) is described for the quantitative analysis of the proteinic stroke biomarker S100-ß that has to be detected at very low concentration levels. The Raman reporter 5,5'-dithiobis-2-nitrobenzoic acid (DTNB) on gold nanoparticles (GNPs) was employed as the SERS tags. They are shown to perform much better than bare GNPs in LF strips. The S100-ß protein can be detected by this method with very low detection limits by monitoring the intensity of the characteristic Raman peak of the S100-ß protein-conjugated GNPs at 1332 cm-1. Under optimized conditions, the assay works in the 1 pg·mL-1 to 40 ng·mL-1 S100-ß concentration range, and the detection limit is as low as 0.14 pg·mL-1. This is lower by a factor of 3 compared to colorimetric or fluorimetric methods. Graphical abstract Schematic illustration of the configuration (A) and the principle of the SERS-based lateral flow assay for quantification of S100-ß (B).

A photoelectrochemical sandwich immunoassay for protein S100ß, a biomarker for Alzheimer's disease, using an ITO electrode modified with a reduced graphene oxide-gold conjugate and CdS-labeled secondary antibody.

A sandwich-type photoelectrochemical immunoassay is described for the protein S100ß which is an Alzheimer's disease biomarker found in the astrocytes of the brain. Antibody against S100ß (anti-S100ß) was labeled with CdS quantum dots and then acted as a secondary antibody. The labeled antibody was characterized by FTIR, ultraviolet-visible and fluorescence spectroscopy. An indium-tin oxide (ITO) electrode was modified with a nanocomposite prepared from reduced graphene oxide and gold nanoparticles. Then, a sol-gel film containing isocyanate functional groups (-N=C=O) was cast on the surface of the electrode. The NCO group reacts with amino groups of the labeled antibody to covalently bind them to the surface. The S100ß was bound by the primary immobilized antibody on the rGO-Au/ITO electrode and then sandwiched with the labeled secondary antibody. Cyclic voltammetry and electrochemical impedance spectroscopy were applied to confirm the stepwise changes in the electrochemical properties of the electrode surface. The photoelectrochemical immunoassay, typically operated at a potential of +0.2 V (vs. Ag|AgClsat) gives a signal that is related to the logarithm of the S100ß concentration in the range from 0.25 to 10 ng·mL-1 with a lower detection limit of 0.15 pg·mL-1. The method was successfully applied to the determination of S100ß in human serum samples. Graphical abstract Schematic presentation of an immunosensor which is based on an indium tin oxide modified with reduced graphene oxide decorated with gold nanocomposite and antibody. The immunosensor was applied for the determination of S100ß biomarker by using in the labeled antibody.

Regional Cerebral Oxygen Saturation Decreases During Primary Hip Arthroplasty: An Analysis of Perioperative Regional Cerebral Oxygenation (rSO2), S100 Calcium-Binding Protein B (S100B) and Glial Fibrillary Acidic Protein (GFAP) Values. A Pilot Study.

BACKGROUND The incidence of postoperative cognitive dysfunction (POCD) after major joint arthroplasty is high. In the etiology of POCD, many factors have been cited, including thromboembolic complications. The incidence of cerebral embolization after lower extremity arthroplasty may be as high as 40-60%. The potential events of cerebral embolization could lead to a decrease in the regional cerebral oxygenation (rSO2) and increased serum levels of biochemical markers of brain damage. The objective of the study was to test whether there are any changes in the rSO2 values and serum markers of brain damage in patients who underwent total hip arthroplasty. MATERIAL AND METHODS Fifteen patients who underwent primary hip arthroplasty under spinal anesthesia were analyzed. The rSO2 was monitored using infrared spectroscopy. Biochemical analyses of S100 calcium-binding protein B (S100B) protein and fibrillary acidic protein (GFAP) serum concentrations were performed using immunoassay methods. RESULTS The values of rSO2 decreased during the surgery, but this was not related to mean arterial pressure variations or hemoglobin saturation. The concentration of S100B was increased compared to its preoperative values, and there were no changes in GFAP values. The changes in rSO2 readings correlated with the biomarkers' levels just after the surgery. CONCLUSIONS Our results suggest that S100B may be a more specific marker of astroglial damage in patients after primary total hip arthroplasty. The decrease in rSO2 readings may be due to micro-thromboembolic events that occurred during the surgery. However, the results of this study are preliminary, and further studies are needed to establish its clinical efficacy.