SERS characterization of aggregated and isolated bacteria deposited on silver-based substrates.

Surface-enhanced Raman scattering (SERS), based on the enhancement of the Raman signal of molecules positioned within a few nanometres from a structured metal surface, is ideally suited to provide bacterial-specific molecular fingerprints which can be used for analytical purposes. However, for some complex structures such as bacteria, the generation of reproducible SERS spectra is still a challenging task. Among the various factors influencing the SERS variability (such as the nature of SERS-active substrate, Raman parameters and bacterial specificity), we demonstrate in this study that the environment of Gram-positive and Gram-negative bacteria deposited on ultra-thin silver films also impacts the origin of the SERS spectra. In the case of densely packed bacteria, the obtained SERS signatures were either characteristic of the secretion of adenosine triphosphate for Staphylococcus aureus (S. aureus) or the cell wall and the pili/flagella for Escherichia coli (E. coli), allowing for an easy discrimination between the various strains. In the case of isolated bacteria, SERS mapping together with principal component analysis revealed some variabilities of the spectra as a function of the bacteria environment and the bactericidal effect of the silver. However, the variability does not preclude the SERS signatures of various E. coli strains to be discriminated.

Rapid and sensitive identification of uropathogenic Escherichia coli using a surface-enhanced-Raman-scattering-based biochip.

Rapid, selective and sensitive sensing of bacteria remains challenging. We report on a highly sensitive and reproducible surface-enhanced Raman spectroscopy (SERS)-based sensing approach for the detection of uropathogenic Escherichia coli (E. coli) bacteria in urine. The assay is based on the specific capture of the bacteria followed by interaction with cetyltrimethylammonium bromide (CTAB)-stabilised gold nanorods (Au NRS) as SERS markers. High sensitivity up to 10 CFU mL-1 is achieved by optimizing the capture interface based on hydrogenated amorphous silicon a-Si:H thin films. The integration of CH3O-PEG750 onto a-Si:H gives the sensing interface an efficient anti-fouling character, while covalent linkage of antibodies directed against the major type-1 fimbrial pilin FimA of the human pathogen E. coli results in the specific trapping of fimbriated E. coli onto the SERS substrate and their spectral fingerprint identification.

Advancements on phenotypic and functional characterization of non-antigen-specific CD8+CD28- regulatory T cells.

Among the different regulatory T lymphocyte (Treg) subpopulations, non-antigen-specific CD8+CD28- Treg (CD8+CD28- Treg) have been characterized for being involved in the pathogenesis of autoimmune diseases and cancer. A better phenotypic and functional characterization of this regulatory T-cell subset could help in identifying modulators of their activity with therapeutic finalities. The results of the present work show that Foxp3, a transcriptional marker of natural CD4+CD25+ Treg, is not expressed by CD8+CD28- Treg, thus indicating different origin and pathways of function for the latter with respect to the former regulatory cell type. Moreover, the results underline that the glucocorticoid induced TNF receptor is involved in generation processes but not in suppressor function of CD8+CD28- Treg. Phenotypic analyses demonstrate that, during their commitment from circulating nonregulatory CD8+CD28- T lymphocytes to Treg (an interleukin-10-dependent process), these cells downmodulate the IL7-receptor, thus differentiating them from long-lived, memory CD8+ T lymphocytes. Interestingly, CD8+CD28- Treg have been found to be resistant to the inhibitory effects of methylprednisolone, one of the most frequently administered corticosteroid drug used in therapy for immunosuppressive purposes.

The prevalence of crown injuries to frontal teeth at schoolchildren aged 6 to 14 and their effects on the periodontal tissue.

The research aims at emphasizing the interrelation between the social impact and the self-esteem of schoolchildren with dental crown fractures in the frontal group. Dental traumatic injuries are frequently met to schoolchildren, therefore, the prevention and interception of traumatic pathology within parents, teachers and children is more than necessary. Our statistical study intends to determine the prevalence of dental trauma to southwestern Romanian schoolchildren aged 6 to 14. The survey included a number of 1684 schoolchildren attending public schools, randomly chosen. Data were collected from October 2012 to December 2013. Clinical examination was conducted to assess the dental traumatic injuries. Age and gender distribution, etiological factors, risk factors and the cause of injuries were the parameters taken into consideration. The data collected was processed and analyzed using the SPSS (Statistical Package for the Social Sciences) statistical software. The overall prevalence of dental trauma was 4.63% amongst the subjects examined. The maxillary central incisor was the most commonly affected tooth (85.19% in boys and 97.87% in girls). We observed a significant statistical difference in the number of children with one, two or three fractured teeth from the urban and rural areas. The percentage of schoolchildren with crown fractures that we examined was of 3.09% in the urban area and 1.54% in the rural area. The traumatic injuries of the maxillary upper teeth were most prevalent. Since the dental trauma of incisors has a strong impact on the quality of life of children and their families, health preventive policies are needed in order to avoid psychological implications on the lifelong existence of children affected.

Clinico-statistical and morphological aspects of severe traumatic brain injuries.

Traumatic brain injuries (TBIs) represent a problem of public health all over the world if we consider its incidence, mortality and the big social costs. The increase of road and train traffic, the development of industry, the growth of alcohol consumption, the emergence and increase of terrorist attacks have led to more frequent and severe TBIs. There were registered 3260 deaths at the Institute of Forensic Medicine in Craiova, Romania, between 2010 and 2014; they were the result of severe traumas, 622 (19.07%) being caused by TBIs. The most affected by TBIs were men (the men÷women ratio was of 3÷1) and the elderly, mainly in the rural area. The main risk factor was alcohol intake; about 44% of the deceased people were under alcohol influence. The forensic examination highlighted the severity of cerebral meningeal lesions, the most frequent being cerebral and vascular lesions. The histopathological and immunohistochemical examinations emphasized various microscopic changes in accordance with the severity of the trauma and the time passed from impact until death.

Cytokines and fever.

Cytokines are highly inducible, secreted proteins mediating intercellular communication in the nervous and immune system. Fever is the multiphasic response of elevation and decline of the body core temperature regulated by central thermoregulatory mechanisms localized in the preoptic area of the hypothalamus. The discovery that several proinflammatory cytokines act as endogenous pyrogens and that other cytokines can act as antipyretic agents provided a link between the immune and the central nervous systems and stimulated the study of the central actions of cytokines. The proinflammatory cytokines interleukin 1 (IL-1), interleukin 6 (IL-6) and the tumor necrosis factor alpha (TNF) as well as the antiinflammatory cytokines interleukin 1 receptor antagonist (IL-1ra) and interleukin 10 (IL-10) have been most investigated for their pyrogenic or antipyretic action. The experimental evidence demonstrating the role of these secreted proteins in modulating the fever response is as follows: 1) association between cytokine levels in serum and CSF and fever; 2) finding of the presence of cytokine receptors on various cell types in the brain and demonstration of the effects of pharmacological application of cytokines and of their neutralizing antibodies on the fever response; 3) fever studies on cytokine- and cytokine receptor- transgenic models. Studies on the peripheral and the central action of cytokines demonstrated that peripheral cytokines can communicate with the brain in several ways including stimulation of afferent neuronal pathways and induction of the synthesis of a non cytokine pyrogen, i.e. PGE2, in endothelial cells in the periphery and in the brain. Cytokines synthesized in the periphery may act by crossing the blood brain barrier and acting directly via neuronal cytokine receptors. The mechanisms that ultimately mediate the central action of cytokines and of LPS on the temperature-sensitive neurons in the preoptic hypothalamic region involved in thermoregulation, directly or via second mediators, remain to be fully elucidated.

Phospholipases C and A2 control lysosome-mediated IL-1 beta secretion: Implications for inflammatory processes.

Blocking the activity of IL-1 beta has entered the clinical arena of treating autoimmune diseases. However, a successful outcome of this approach requires a clear definition of the mechanisms controlling IL-1 beta release. These are still unclear as IL-1 beta, lacking a secretory signal peptide, follows a nonclassical pathway of secretion. Here, we analyze the molecular mechanism(s) undergoing IL-1 beta processing and release in human monocytes and provide a unifying model for the regulated secretion of the cytokine. Our data show that in a first step, pro-caspase-1 and endotoxin-induced pro-IL-1 beta are targeted in part to specialized secretory lysosomes, where they colocalize with other lysosomal proteins. Externalization of mature IL-1 beta and caspase-1 together with lysosomal proteins is then facilitated by extracellular ATP. ATP triggers the efflux of K(+) from the cell, followed by Ca(2+) influx and activation of three phospholipases: phosphatidylcholine-specific phospholipase C and calcium-independent and -dependent phospholipase A(2). Whereas calcium-independent phospholipase A(2) is involved in processing, phosphatidylcholine-specific phospholipase C and calcium-dependent phospholipase A(2) are required for secretion. Dissection of the events that follow ATP triggering allowed to demonstrate that K(+) efflux is responsible for phosphatidylcholine-specific phospholipase C induction, which in turn allows the rise in intracellular free calcium concentration required for activation of phospholipase A(2). This activation is ultimately responsible for lysosome exocytosis and IL-1 beta secretion.

The nuclear protein HMGB1 is secreted by monocytes via a non-classical, vesicle-mediated secretory pathway.

HMGB1, a non-histone nuclear factor, acts extracellularly as a mediator of delayed endotoxin lethality, which raises the question of how a nuclear protein can reach the extracellular space. We show that activation of monocytes results in the redistribution of HMGB1 from the nucleus to cytoplasmic organelles, which display ultrastructural features of endolysosomes. HMGB1 secretion is induced by stimuli triggering lysosome exocytosis. The early mediator of inflammation interleukin (IL)-1beta is also secreted by monocytes through a non-classical pathway involving exocytosis of secretory lysosomes. However, in keeping with their respective role of early and late inflammatory factors, IL-1beta and HMGB1 respond at different times to different stimuli: IL-1beta secretion is induced earlier by ATP, autocrinally released by monocytes soon after activation; HMGB1 secretion is triggered by lysophosphatidylcholine, generated later in the inflammation site. Thus, in monocytes, non-classical secretion can occur through vescicle compartments that are at least partially distinct.