Using SWATH-MS to identify new molecular biomarkers in gingival crevicular fluid for detecting periodontitis and its response to treatment.

AIM: To identify new biomarkers to detect untreated and treated periodontitis in gingival crevicular fluid (GCF) using sequential window acquisition of all theoretical mass spectra (SWATH-MS). MATERIALS AND METHODS: GCF samples were collected from 44 periodontally healthy subjects and 40 with periodontitis (Stages III-IV). In the latter, 25 improved clinically 2 months after treatment. Samples were analysed using SWATH-MS, and proteins were identified by the UniProt human-specific database. The diagnostic capability of the proteins was determined with generalized additive models to distinguish the three clinical conditions. RESULTS: In the untreated periodontitis vs. periodontal health modelling, five proteins showed excellent or good bias-corrected (bc)-sensitivity/bc-specificity values of >80%. These were GAPDH, ZG16B, carbonic anhydrase 1, plasma protease inhibitor C1 and haemoglobin subunit beta. GAPDH with MMP-9, MMP-8, zinc-α-2-glycoprotein and neutrophil gelatinase-associated lipocalin and ZG16B with cornulin provided increased bc-sensitivity/bc-specificity of >95%. For distinguishing treated periodontitis vs. periodontal health, most of these proteins and their combinations revealed a predictive ability similar to previous modelling. No model obtained relevant results to differentiate between periodontitis conditions. CONCLUSIONS: New single and dual GCF protein biomarkers showed outstanding results in discriminating untreated and treated periodontitis from periodontal health. Periodontitis conditions were indistinguishable. Future research must validate these findings.

The poor accuracy of D-dimer for the diagnosis of prosthetic joint infection but its potential usefulness in early postoperative infections following revision arthroplasty for aseptic loosening.

BACKGROUND: D-dimer was introduced in 2018 as an alternative biomarker for C-reactive protein (CRP) in the diagnostic of prosthetic joint infection (PJI) criteria of the Musculoskeletal Infection Society. We assessed the accuracy of plasma D-dimer for the diagnosis of early, delayed, and late PJI according to Infectious Diseases Society of America (IDSA) criteria, and whether persistently high levels of D-dimer in cases of aseptic loosening (AL) may be predictive of subsequent implant-related infection. METHODS: A prospective study of a consecutive series of 187 revision arthroplasties was performed at a single institution. Septic (n = 39) and aseptic revisions (n = 141) were classified based on IDSA criteria. Preoperative assessment of CRP, erythrocyte sedimentation rate (ESR) and D-dimer was performed. Receiver operating curves were used to determine maximum sensitivity and specificity of the biomarkers. The natural progress of D-dimer for AL cases was followed up either until the date of implant-related infection at any time during the first year or 1 year after revision in patients without failure. Clinical outcomes for those AL cases included infection-related failure that required a new surgery or need for antibiotic suppression. RESULTS: Preoperative D-dimer level was significantly higher in PJI cases than in AL cases (p = 0.000). The optimal threshold of D-dimer for the diagnosis of PJI was 1167 ng/mL. For overall diagnosis of PJI, C-reactive protein (CRP) achieved the highest sensitivity (84.6%), followed by erythrocyte sedimentation rate (ESR) and D-dimer (82% and 71.8%, respectively). Plasma D-dimer sensitivity was lower for all PJI types. When combinations of 2 tests were studied, the combined use of ESR and CRP achieved the best accuracy for all types of PJI (76.9%). 4.25% of AL cases had implant failure due to implant-related infection during the first year after the index revision arthroplasty, only the cases with early failure maintained high D-dimer levels. CONCLUSIONS: Plasma D-dimer did not offer an improvement over the individual or combined diagnosis for any type of PJI according to IDSA criteria. Persistently raised levels of D-dimer after revision arthroplasty in AL cases might be used to effectively diagnose early postoperative infection.

Plastidial Phosphoglucose Isomerase Is an Important Determinant of Seed Yield through Its Involvement in Gibberellin-Mediated Reproductive Development and Storage Reserve Biosynthesis in Arabidopsis.

The plastid-localized phosphoglucose isomerase isoform PGI1 is an important determinant of growth in Arabidopsis thaliana, likely due to its involvement in the biosynthesis of plastidial isoprenoid-derived hormones. Here, we investigated whether PGI1 also influences seed yields. PGI1 is strongly expressed in maturing seed embryos and vascular tissues. PGI1-null pgi1-2 plants had ∼60% lower seed yields than wild-type plants, with reduced numbers of inflorescences and thus fewer siliques and seeds per plant. These traits were associated with low bioactive gibberellin (GA) contents. Accordingly, wild-type phenotypes were restored by exogenous GA application. pgi1-2 seeds were lighter and accumulated ∼50% less fatty acids (FAs) and ∼35% less protein than wild-type seeds. Seeds of cytokinin-deficient plants overexpressing CYTOKININ OXIDASE/DEHYDROGENASE1 (35S:AtCKX1) and GA-deficient ga20ox1 ga20ox2 mutants did not accumulate low levels of FAs, and exogenous application of the cytokinin 6-benzylaminopurine and GAs did not rescue the reduced weight and FA content of pgi1-2 seeds. Seeds from reciprocal crosses between pgi1-2 and wild-type plants accumulated wild-type levels of FAs and proteins. Therefore, PGI1 is an important determinant of Arabidopsis seed yield due to its involvement in two processes: GA-mediated reproductive development and the metabolic conversion of plastidial glucose-6-phosphate to storage reserves in the embryo.

Safety and Efficacy of Prolonged Use of Dalbavancin in Bone and Joint Infections.

Dalbavancin is a lipoglycopeptide with potent activity against Gram-positive microorganisms, a long half-life, a favorable safety profile, and a high concentration in bone, which makes it an interesting alternative for treatment of osteoarticular infections. We performed a multicentric retrospective study of all patients with an osteoarticular infection (septic arthritis, spondylodiscitis, osteomyelitis, or orthopedic implant-related infection) treated with at least one dose of dalbavancin between 2016 and 2017 in 30 institutions in Spain. In order to evaluate the response, patients with or without an orthopedic implant were separated. A total of 64 patients were included. Staphylococcus epidermidis and Staphylococcus aureus were the most frequent microorganisms. The reasons for switching to dalbavancin were simplification (53.1%), adverse events (25%), or failure (21.9%). There were 7 adverse events, and no patient had to discontinue dalbavancin. In 45 cases, infection was related to an orthopedic implant. The implant material was retained in 23 cases, including that in 15 (65.2%) patients that were classified as cured and 8 (34.8%) that presented improvement. In 21 cases, the implants were removed, including those in 16 (76.2%) cases that were considered successes, 4 (19%) cases were considered improved, and 1 (4.8%) case that was considered a failure. Among the 19 cases without implants, 14 (73.7%) were considered cured, 3 (15.8%) were considered improved, and 2 (10.5%) were considered failures. The results show that dalbavancin is a well-tolerated antibiotic, even when >2 doses are administered, and is associated with a high cure rate. These are preliminary data with a short follow-up; therefore, it is necessary to gain more experience and, in the future, to establish the most appropriate dose and frequency.

Fusobacterium nucleatum prosthetic hip infection: Case report and review of the literature of unusual anaerobic prosthetic joint infection.

The anaerobic Gram-negative rod Fusobacterium nucleatum is an oral commensal and periodontal pathogen that has been associated with a wide variety of infections, yet it is extremely rare to be associated with prosthetic joint infection. After an exhaustive literature review, only two cases of prosthetic joint infection by F. nucleatum have been previously reported. To our knowledge, the case we report on here is the first combined with periprosthetic abscess and related with hemochromatosis. We therefore sought to provide a comprehensive literature review of case reports or series of less commonly encountered anaerobic microorganisms isolated from prosthetic joint infections.

Accuracy of different diagnostic tests for early, delayed and late prosthetic joint infection.

BACKGROUND: A combination of laboratory, histopathological and microbiological tests for diagnosis of prosthetic joint infection (PJI) have been strongly recommended. This study aims to characterize the accuracy of individual or group tests, such as culture of sonicate fluid, synovial fluid and peri-implant tissue, C-reactive protein (CRP) and histopathology for detection of early, delayed and late PJI. METHODS: A prospective study of patients undergoing hip or knee arthroplasty from February 2009 to February 2014 was performed in a Spanish tertiary health care hospital. The diagnostic accuracy of the different methods was evaluated constructing receiver-operating-characteristic (ROC) curve areas. RESULTS: One hundred thirty consecutive patients were included: 18 (13.8%) early PJI, 35 (27%) delayed PJI and 77 (59.2%) late PJI. For individual parameters, the area under the ROC curve for peri-implant tissue culture was larger for early (0.917) than for delayed (0.829) and late PJI (0.778), p = 0.033. There was a significantly larger difference for ROC area in the synovial fluid culture for delayed (0.803) than for early (0.781) and late infections (0.679), p = 0.039. The comparison of the areas under the ROC curves for the two microbiological tests showed that sonicate fluid was significantly different from peri-implant tissue in delayed (0.951 vs 0.829, p = 0.005) and late PJI (0.901 vs 0.778, p = 0.000). The conjunction of preoperative parameters, synovial fluid culture and CRP, improved the accuracy for late PJI (p = 0.01). The conjunction of histopathology and sonicate fluid culture increased the area under ROC curve of sonication in early (0.917 vs 1.000); p = 0.06 and late cases (0.901 vs 0.999); p < 0.001. CONCLUSION: For early PJI, sonicate fluid and peri-implant tissue cultures achieve the same best sensitivity. For delayed and late PJI, sonicate fluid culture is the most sensitive individual diagnostic method. By combining histopathology and peri-implant tissue, all early, 97% of delayed and 94.8% of late cases are diagnosed. The conjunction of histopathology and sonicate fluid culture yields a sensitivity of 100% for all types of infection.

Cross-sectional study about impact of parental smoking on rhinitis symptoms in children.

OBJECTIVE: Assess the prevalence of rhinitis and exposure to environmental tobacco smoke (ETS) of children in our community and its relationship with symptoms of rhinitis METHODS (DESIGN, SETTING, PARTICIPANTS, MAIN OUTCOME MEASURES): Cross-sectional study using questionnaire on rhinitis of the International Study of Asthma and Allergies in Childhood, in children (6-7 years) and adolescents (13-14 years). Categories: "rhinitis ever", "recent rhinitis", "recent rhinoconjunctivitis", "severe rhinoconjunctivitis". Parental smoking: (i) neither parent smokes; (ii) only the mother smokes; (iii) only the father smokes; and (iv) both parents smoke. Odds ratio of the prevalence of symptoms of rhinitis according to ETS exposure was calculated using logistic regression. RESULTS: 10 690 children and 10 730 adolescents. The prevalence of "rhinitis ever" in children: 29.4%, "recent rhinitis" 24%, "recent rhinoconjunctivitis" 11.5% and "severe rhinoconjunctivitis" 0.1%. In adolescents: 46.2%, 34.5%, 16.2% and 0.2%, respectively. Environmental tobacco smoke exposure in the home occurred in 51% of cases. Parental smoking was associated with a higher prevalence of forms of rhinitis in adolescents when only the mother was a smoker. In children when both parents were smokers. CONCLUSION: Rhinitis is highly prevalent in our community. Environmental tobacco smoke exposure is still very common. The relationship between ETS and rhinitis symptoms in children of this community is not as robust as that found for asthma.

[Proposing a workload indicator for hospital at home patients in Osakidetza - Basque Public Health Service]. / Propuesta de un indicador de cargas de trabajo en la atención de pacientes en hospitalización a domicilio de Osakidetza ­ Servicio Vasco de Salud.

INTRODUCTION AND OBJECTIVES: The Hospital at Home (HaH) setting currently lacks adequate workload indicators. This study suggests an indicator that can help in improving professional resources allocation. MATERIALS AND METHODS: Prospective data was collected during May 2021 from patients treated in nine HaH units of Osakidetza-Basque Health Service (North of Spain). Direct care and travel times of healthcare staff was recorded. Data on inpatient days, number of visits, sociodemographic variables, health status, and patient pathologies, among others, were collected. The proposed indicator encompasses both the average visit time and the visit rates. It is called intensity and represents the average daily workload time per patient. RESULTS: A total of n = 1,171 users were included in the analyses. Their mean age was 69.8 years, 45.5% were women and 25% lived more than 12 km away from the corresponding HaH unit. Workload variations were observed for nursing-only and medical-nursing teams, depending on the type of day and patient classification group. The average nursing-only teams workload time on working days was 10.82 min and on non-working days it was 14.78 min. The average workload time for medical-nursing teams, during the same days, was 20.40 min and 4.59 min, respectively. It was observed that certain patient types, like those in palliative care, represented a high workload for medical-nursing teams on working days. CONCLUSIONS: The intensity indicator can help answering the question of how many patients can be assigned to a professional. It can also be used to adjust the staffing needs of the HaH units.

Obesity and asthma: an association modified by age.

BACKGROUND: Some studies indicate some causal relationship between obesity and asthma, while others show inconsistent results. Our objective was to evaluate the prevalence of asthma according to obesity in children. METHODS: A cross-sectional study, following the ISAAC study methodology, was conducted on two randomly selected groups consisting of 6-7 year-old children (n=7485) and 13-14 year-old adolescents (n=8496). The asthma symptoms and potential risk factors were determined from the questionnaire. Overweight and obesity were defined based on the body mass index. Multiple logistic regression was used to obtain adjusted prevalence odds ratios (OR) and 95% confidence intervals. RESULTS: Obesity was associated with an increase in wheezing ever (OR: 1.35) and exercise-induced asthma (OR: 1.62) in the 6-7 year-old group. No significant relationship was observed in the adolescent population. CONCLUSION: Obesity was associated with a higher prevalence of asthma in young children, but not in adolescents.

Truck traffic related air pollution associated with asthma symptoms in young boys: a cross-sectional study.

OBJECTIVES: The aim of this study was to evaluate the influence of intensity of truck traffic on asthma symptomatology, and its relationship with age and gender. STUDY DESIGN: A cross-sectional study was conducted on children and adolescents from Galicia (North-West Spain). METHODS: Following the methodology of the International Study of Asthma and Allergies in Childhood (ISAAC): children from schools randomly selected, answered a self-administered questionnaire included questions on asthma symptoms and some risk factors. The association between self-reported truck traffic on the street of residence and symptoms of asthma were investigated by logistic regression adjusted for body mass index, maternal education and parental smoking. RESULTS: Almost 40% of children in Galicia are exposed to the frequent and constant passing of heavy goods vehicles. The odds of 6-7 year-old boys having severe or exercise induced asthma is tripled when they live in streets with the constant passing of heavy goods vehicles, compared with those living in streets where these vehicles never pass. In adolescents and 6-7 year-old girls, no relationship was observed between truck traffic and asthma symptoms. CONCLUSIONS: The results of this study appear to support a distinct effect of truck traffic on asthma symptoms depending on the age and sex of the exposed population, being more harmful for young males.

[Factors associated with the hospital at home workload: A Delphi consensus study]. / Factores relacionados con la carga de trabajo en hospitalización a domicilio: estudio de consenso Delphi.

OBJECTIVES: To identify and prioritize a list of factors that contribute to the workload of the hospital at home (HaH) professionals. MATERIAL AND METHODS: A qualitative methodology study performed between January and December 2019 in the 10 HAH units of the Basque Country. The data were obtained in 4phases: 1. Systematic literature search and review; 2. Expert group meeting; 3. Consensus method: Delphi technique (2 survey rounds) and nominal group meeting; 4. Meeting of the research team. RESULTS: In the systematic literature search and review 85 factors were initially identified. These were reduced to 38 after the 8-person expert group meeting, in which 10 new factors were added. After the 2 Delphi rounds (106 and 57 professionals, respectively), 17 factors were maintained and 12 remained in doubt. The latter were evaluated at the nominal group meeting, consisting of 13 professionals who decided to eliminate 5 factors, include 3, and keep 3 as doubt. After the 8-person research team meeting, 14 potential factors were finally selected. They are related to the place of residence, the health state and social situation of the patients, as well as the health care provided at home. CONCLUSIONS: The identified factors could serve for improving the organization and optimize the daily word of the HaH professionals.

PM-Scl and Th/To in systemic sclerosis: a comparison of different autoantibody assays.

OBJECTIVE: To compare test characteristics of the Euroimmun line blot assay with other assays for two uncommon autoantibody specificities in systemic sclerosis (SSc). METHODS: Patients from the Johns Hopkins Scleroderma Center were assayed routinely using the Euroimmun platform. Patients positive for anti-Th/To (N = 73) and anti-PM-Scl (PM75 and/or PM100; N = 290) by Euroimmun were compared with SSc patients negative for these autoantibodies. For Th/To antibodies, the comparison assay was immunoprecipitation (IP), performed using 4 Th/To complex components: POP1, RPP40, RPP30, and RPP25. For anti-PM-Scl, IPs were performed with PM100 and PM75. Different Euroimmun cut-offs for assigning antibody positive status (≥ 15/+, ≥ 36/++, ≥ 71/+++) were examined. Kappa statistics were calculated to determine agreement between assays. RESULTS: The best performing thresholds for defining anti-PM-Scl positivity were both PM75 and PM100 ≥ 15/+ on Euroimmun, corresponding to a kappa statistic of 0.79, sensitivity 72% and specificity 100%. For anti-Th/To, kappa values were lower for all comparisons (κ < 0.5). Given the high sensitivity of defining anti-Th/To by ≥ 15/+ (91-95%), a potential approach is to use Euroimmun screening (15/+ cut-off), followed by confirmatory IP. CONCLUSION: Given the increasing utilization of Euroimmun and the importance of comparing data across cohorts, continued use of this platform is warranted, acknowledging discordance with IP for some specificities. For these, using a two-step approach (Euroimmun to maximize sensitivity, confirmatory assay to increase specificity) is suggested. KEY POINTS: • For less common SSc autoantibody specificities, some discordances exist between IP and Euroimmun LIA. • The best performing thresholds for defining anti-PM-Scl positivity were both PM75 and PM100 ≥ 15/+ on Euroimmun. • For Th/To, a two-step approach (Euroimmun to maximize sensitivity, confirmatory assay to increase specificity) is suggested.

Inhibition of proliferation of normal and transformed neural cells by blood group-related oligosaccharides.

A synthetic tetrasaccharide structurally related to blood groups and selectin ligands inhibited division of astrocytes, gliomas, and neuroblastomas at micromolar concentrations. The compound was cytostatic for primary astrocytes in culture, but cytotoxic for fast proliferating cell lines.

Mediterranean diet and asthma in Spanish schoolchildren.

There is still debate on the effect of dietetic factors on the prevalence or severity of asthma, as well as the interaction with other factors. We have analysed the prevalence and severity of asthma according to adherence to the Mediterranean diet (MD), its association with obesity and family life style. We performed a cross-sectional study on 14,700 children and adolescents in six health areas in our region. We used the International Study of Asthma and Allergies in Childhood questionnaire to collect asthma symptoms, dietary habits, anthropometric parameters, parental smoking habits and maternal education level. The diet pattern was analysed using a Mediterranean Diet Score. In the logistic regression we analysed the influence of adhering to the MD on the prevalence and severity of asthma, adjusted for the other parameters included. Greater adherence to the MD is associated with a higher risk of severe asthma (odds ratios = 2.26, 95% CI: 1.21-4.22) in girls of 6-7 yr. There was no significant relationship for the other asthma categories in the population studied. The results of our study do not support a protective effect of the MD on the prevalence or severity of asthma.

Interplay between 1-aminocyclopropane-1-carboxylic acid, γ-aminobutyrate and D-glucose in the regulation of high nitrate-induced root growth inhibition in maize.

Nitrogen is one of the main factors that affect plant growth and development. However, high nitrogen concentrations can inhibit both shoot and root growth, even though the processes involved in this inhibition are still unknown. The aim of this work was to identify the metabolic alterations that induce the inhibition of root growth caused by high nitrate supply, when the whole plant growth is also reduced. High nitrate altered nitrogen and carbon metabolism, reducing the content of sugars and inducing the accumulation of Ca2+ and amino acids, such as glutamate, alanine and γ-aminobutyrate (GABA), that could act to replenish the succinate pool in the tricarboxylic acid cycle and maintain its activity. Other metabolic alterations found were the accumulation of the polyamines spermidine and spermine, and the reduction of jasmonic acid (JA) and the ethylene precursor aminocyclopropane-1-carboxylic acid (ACC). These results indicate that the growth root inhibition by high NO3- is a complex metabolic response that involves GABA as a key link between C and N metabolism which, together with plant growth regulators such as auxins, cytokinins, abscisic acid, JA, and the ethylene precursor ACC, is able to regulate the metabolic response of root grown under high nitrate concentrations.

Particle Analysis for the Detection of Gunshot Residue (GSR) in Nasal Samples Using Scanning Laser Ablation and Inductively Coupled Plasma-Mass Spectrometry (SLA-ICPMS).

Currently, aluminum stub with carbon adhesive devices are used to collect inorganic gunshot residues (GSR) from the hands of a shooter. In an ideal shooting case, the gunshot particles do not persist for more than 2 h in the hands of the shooter, provided that the hands have not been washed. However, for forensic analysis and inference, the extended persistence of GSR would be desirable. This study investigates a novel GSR sampling and detection protocol. Sampling was performed in the nostrils using swab devices impregnated in ethylenediaminetetraacetic acid (EDTA). The GSRs persisted for longer periods in nasal mucus than on the hands, and particles were detected 6 h after shooting occurred. The analytical determination was conducted by scanning laser ablation-inductively coupled plasma-mass spectrometry (SLA-ICPMS) which enable the identification of the number of particles and their elemental composition. Seventeen isotope signals corresponding to 13 C, 205 Tl and 15 analytes that are usually associated with the composition of GSR residues were monitored: 27 Al, 29 Si, 31 P, 33 S, 35 Cl, 39 K, 44 Ca, 57 Fe, 60 Ni, 63 Cu, 66 Zn, 118 Sn, 121 Sb, 137 Ba, and 208 Pb. The SLA technique enabled the reduction of the swab analysis time to 40 min. The effectiveness of this methodology was evaluated with two types of firearms: a pistol and a shotgun. The results indicated that the methodology proposed for the analysis of the nasal GSR was effective and that it can improve or complement the forensic analyses and inferences presented in a court.

Postsynaptic density antigens: preparation and characterization of an antiserum against postsynaptic densities.

Long-term immunization of rabbits with postsynaptic densities (PSD) from bovine brain produced an antiserum specific for PSD as judged by binding to subcellular fractions and immunohistochemical location at the light and electron microscope levels. (a) The major antigens of bovine PSD preparations were three polypeptides of molecular weight 95,000 (PSD-95), 82,000 (PSD-82), and 72,000 (PSD-72), respectively. Antigen PSD-95, also present in mouse and rat PSDs was virtually absent from cytoplasm, myelin, mitochondria, and microsomes from rodent or bovine brain. Antigens PSD-82 and PSD-72 were present in all subcellular fractions from bovine brain, especially in mitochondria, but were almost absent from rodent brain. The antiserum also contained low-affinity antibodies against tubulin. (b)Immunohistochemical studies were performed in mouse and rat brain, where antigen PSD-95 accounted for 90 percent of the antiserum binding after adsorption with purified brain tubulin. At the light microscope level, antibody binding was observed only in those regions of the brain where synapses are known to be present. No reaction was observed in myelinated tracts, in the neuronal cytoplasm, or in nonneuronal cells. Strong reactivity was observed in the molecular layer of the dentate gyrus, stratum oriens and stratum radiatum of the hippocampus, and the molecular layer of the cerebellum. Experimental lesions, such as ablation of the rat entorhinal cortex or intraventricular injection of kainic acid, which led to a major loss of PSD in well- defined areas of the hippocampal formation, caused a correlative decrease in immunoreactivity in these areas. Abnormal patterns of immunohistochemical staining correlated with abnormal synaptic patterns in the cerebella of reeler and staggerer mouse mutants. (c) At the electron microscopic level, immunoreactivity was detectable only in PSD. The antibody did not bind to myelin, mitochondria or plasma membranes. (d) The results indicate that antigen PSD-95 is located predominantly or exclusively in PSD and can be used as a marker during subcellular fractionation. Other potential uses include the study of synaptogenesis, and the detection of changes in synapse number after experimental perturbations of the nervous system.

Astrocyte mitogen inhibitor related to epidermal growth factor receptor.

Epidermal growth factor (EGF) is a well-characterized polypeptide hormone with diverse biological activities, including stimulation of astrocyte division. A soluble astrocyte mitogen inhibitor, immunologically related to the EGF receptor, is present in rat brain. Injury to the brain causes a time-dependent reduction in the levels of this inhibitor and the concomitant appearance of EGF receptor on the astrocyte surface. Intracerebral injection of antibody capable of binding the inhibitor caused the appearance of numerous reactive astrocytes. EGF receptor-related inhibitors may play a key role in the control of glial cell division in both normal and injured brain.