Subtle vascular and astrocytic changes in the brain of coronavirus disease 2019 (COVID-19) patients.

BACKGROUND AND PURPOSE: In the central nervous system, a multitude of changes have been described associated with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection, such as microglial activation, perivascular lymphocyte cuffing, hypoxic-ischaemic changes, microthrombosis, infarcts or haemorrhages. It was sought here to assess the vascular basement membranes (vBMs) and surrounding perivascular astrocytes for any morphological changes in acute respiratory syndrome (coronavirus disease 2019, COVID-19) patients. METHODS: The light microscopy morphology of the vBMs and perivascular astrocytes from brains of 14 patients with confirmed SARS-CoV-2 infection was analysed and compared to four control patients utilizing fluorescent immunohistochemistry for collagen IV and astrocytes (GFAP), endothelia (CD31), tight junction 1 (TJ1) adhesion protein, as well as the aquaporin 4 (AQP4) water channel. On 2D and 3D deconvoluted images from the cortex and white matter, vessel densities, diameters, degree of gliosis, collagen IV/GFAP and GFAP/AQP4 colocalizations were calculated, as well as the fractal dimension of astrocytes and vBMs viewed in tangential planes. RESULTS: Fractal dimension analysis of the GFAP-stained astrocytes revealed lower branching complexities and decreased GFAP/collagen IV colocalization for COVID-19 patients. Interestingly, vBMs showed significantly increased irregularities (fractal dimension values) compared to controls. Vessel diameters were increased in COVID-19 cases, especially for the white matter, TJ1 protein decreased its colocalization with the endothelia, and AQP4 reduced its co-expression in astrocytes. CONCLUSIONS: Our data on the irregularity of the basement membranes, loss of endothelial tight junction, reduction of the astrocyte end-feet and decrease of AQP4 suggest subtle morphological changes of the blood-brain barrier in COVID-19 brains that could be linked with indirect inflammatory signalling or hypoxia/hypercapnia.

Enhanced Internalization of Nanoparticles Following Ionizing Radiation Leads to Mitotic Catastrophe in MG-63 Human Osteosarcoma Cells.

This study aims to investigate whether ionizing radiation combined with doxorubicin-conjugated iron oxide nanoparticles (NP-DOX) improves the internalization and cytotoxic effects of the nano-carrier-mediated drug delivery in MG-63 human osteosarcoma cells. NP-DOX was designed and synthesized using the co-precipitation method. Highly stable and crystalline nanoparticles conjugated with DOX were internalized in MG-63 cells through macropinocytosis and located in the perinuclear area. Higher nanoparticles internalization in MG-63 cells previously exposed to 1 Gy X-rays was correlated with an early accumulation of cells in G2/M, starting at 12 h after treatment. After 48 h, the application of the combined treatment led to higher cytotoxic effects compared to the individual treatment, with a reduction in the metabolic capacity and unrepaired DNA breaks, whilst a low percent of arrested cells, contributing to the commitment of mitotic catastrophe. NP-DOX showed hemocompatibility and no systemic cytotoxicity, nor histopathological alteration of the main organs.

The Effect of Silver Nanoparticles on Antioxidant/Pro-Oxidant Balance in a Murine Model.

This study aimed to evaluate the subacute effect of two types of Ag-NPs(EG-AgNPs and PVP-EG-AgNPs) on antioxidant/pro-oxidant balance in rats. Seventy Wistar rats (35 males and 35 females) were divided in 7 groups and intraperitoneally exposed for 28 days to 0, 1, 2 and 4 mg/kg bw/day EG-Ag-NPs and 1, 2 and 4 mg/kg bw/day PVP- EG-Ag-NPs. After 28 days, the blood was collected, and the total antioxidant capacity (TAC), thiobarbituric reactive species (TBARS),protein carbonyl (PROTC) levels, reduced glutathione (GSH) levels and catalase (CAT) activity were determined. EG-Ag-NPs determined protective antioxidant effects in a dose-dependent manner. The exposure to the 4 mg/kg bw/day EG-Ag-NPs determines both in males and females a significant increase in TAC and CAT and a significant decrease in TBARS and PROTC only in females. The PVP-EG-AgNPs showed a different trend compared to EG-AgNPs. At 4 mg/kg bw/day the PVP-EG-AgNPs induce increased PROTC levels and decreased GSH (males and females) and TAC levels (males). The different mechanisms of EG-AgNPs and PVP-EG-AgNPs on antioxidant-/pro-oxidant balance can be explained by the influence of coating agent used for the preparation of the nanoparticles in the formation and composition of protein corona that influence their pathophysiology in the organism.

An Immunohistochemical Study of Gastric Mucosa and Critical Review Indicate that the Subepithelial Telocytes are Prelymphatic Endothelial Cells.

There are only a few studies regarding gut subepithelial telocytes (TCs). The telopodes, namely peculiar TCs' prolongations described on two-dimensional cuts, are not enough to differentiate this specific cell type. Subepithelial TCs were associated with the intestinal stem niche but a proper differential diagnosis with lymphatic endothelial cells (LECs) was not performed. In this study, we will critically review studies suggesting that distinctive TCs could be positioned within the lamina propria. Additionally, we performed an immunohistochemical study of human gastric mucosa to test the expression of D2-40, the lymphatic marker, as well as that of CD31, CD34, CD44, CD117/c-kit, α-smooth muscle actin (α-SMA) and vimentin in the gastric subepithelial niche. The results support the poorly investigated anatomy of intramural gastric lymphatics, with circumferential collectors located on both sides of the muscularis mucosae (mucosal and then submucosal) and myenteric collectors in the muscularis propria. We also found superficial epithelial prelymphatic channels bordered by D2-40+ but CD31-TC-like cells. Deep epithelial lymphatic collectors drain in collectors within the lamina propria. Blood endothelial cells expressed CD31, CD34, CD44, and vimentin. Therefore, the positive diagnosis of TC for subepithelial CD34+ cells should be regarded with caution, as they could also be artefacts, resulting from the two-dimensional examination of three dimensional structures, or as LECs. Lymphatic markers should be routinely used to discriminate TCs from LECs.

Myocardial Telocyte-Like Cells: A Review Including New Evidence.

Telocytes (TCs) are a controversial cell type characterized by the presence of a particular kind of prolongations, known as telopodes, which are long, thin, and moniliform. A number of attempts has been made to establish the molecular phenotype of cardiac TCs (i.e., expression of c-kit, CD34, vimentin, PDGRFα, PDGRFß, etc.). We designed an immunohistochemical study involving cardiac tissue samples obtained from 10 cadavers with the aim of determining whether there are TC-like interstitial cells that populate the interstitial space other than the mural microvascular cells. We applied the markers for CD31, CD34, PDGRFα, CD117/c-kit, and α-smooth muscle actin (α-SMA). We found that, in relation to two-dimensional cuts, the endothelial tubes could be misidentified as TC-like cells, the difference being the positive identification of endothelial lumina. Moreover, we found that cardiac pericytes express PDGRFα, CD117/c-kit, and α-SMA, and that they could also be misidentified as TCs when using light microscopy. We reviewed the respective values of the previously identified markers for achieving a clear-cut identification of cardiac TCs, highlighting the critical lack of specificity.

Inhibition of Aquaporin-4 Improves the Outcome of Ischaemic Stroke and Modulates Brain Paravascular Drainage Pathways.

Aquaporin-4 (AQP4) is the most abundant water channel in the brain, and its inhibition before inducing focal ischemia, using the AQP4 inhibitor TGN-020, has been showed to reduce oedema in imaging studies. Here, we aimed to evaluate, for the first time, the histopathological effects of a single dose of TGN-020 administered after the occlusion of the medial cerebral artery (MCAO). On a rat model of non-reperfusion ischemia, we have assessed vascular densities, albumin extravasation, gliosis, and apoptosis at 3 and 7 days after MCAO. TGN-020 significantly reduced oedema, glial scar, albumin effusion, and apoptosis, at both 3 and 7 days after MCAO. The area of GFAP-positive gliotic rim decreased, and 3D fractal analysis of astrocytic processes revealed a less complex architecture, possibly indicating water accumulating in the cytoplasm. Evaluation of the blood vessels revealed thicker basement membranes colocalizing with exudated albumin in the treated animals, suggesting that inhibition of AQP4 blocks fluid flow towards the parenchyma in the paravascular drainage pathways of the interstitial fluid. These findings suggest that a single dose of an AQP4 inhibitor can reduce brain oedema, even if administered after the onset of ischemia, and AQP4 agonists/antagonists might be effective modulators of the paravascular drainage flow.

Bioactive ZnO Coatings Deposited by MAPLE-An Appropriate Strategy to Produce Efficient Anti-Biofilm Surfaces.

Deposition of bioactive coatings composed of zinc oxide, cyclodextrin and cefepime (ZnO/CD/Cfp) was performed by the Matrix Assisted Pulsed Laser Evaporation (MAPLE) technique. The obtained nanostructures were characterized by X-ray diffraction, IR microscopy and scanning electron microscopy. The efficient release of cefepime was correlated with an increased anti-biofilm activity of ZnO/CD/Cfp composites. In vitro and in vivo tests have revealed a good biocompatibility of ZnO/CD/Cfp coatings, which recommend them as competitive candidates for the development of antimicrobial surfaces with biomedical applications. The release of the fourth generation cephalosporin Cfp in a biologically active form from the ZnO matrix could help preventing the bacterial adhesion and the subsequent colonization and biofilm development on various surfaces, and thus decreasing the risk of biofilm-related infections.

Fractal Analysis in Neurodegenerative Diseases.

Neurodegenerative diseases are defined by progressive nervous system dysfunction and death of neurons. The abnormal conformation and assembly of proteins is suggested to be the most probable cause for many of these neurodegenerative disorders, leading to the accumulation of abnormally aggregated proteins, for example, amyloid ß (Aß) (Alzheimer's disease and vascular dementia), tau protein (Alzheimer's disease and frontotemporal lobar degeneration), α-synuclein (Parkinson's disease and Lewy body dementia), polyglutamine expansion diseases (Huntington disease), or prion proteins (Creutzfeldt-Jakob disease). An aberrant gain-of-function mechanism toward excessive intraparenchymal accumulation thus represents a common pathogenic denominator in all these proteinopathies. Moreover, depending upon the predominant brain area involvement, these different neurodegenerative diseases lead to either movement disorders or dementia syndromes, although the underlying mechanism(s) can sometimes be very similar, and on other occasions, clinically similar syndromes can have quite distinct pathologies. Non-Euclidean image analysis approaches such as fractal dimension (FD) analysis have been applied extensively in quantifying highly variable morphopathological patterns, as well as many other connected biological processes; however, their application to understand and link abnormal proteinaceous depositions to other clinical and pathological features composing these syndromes is yet to be clarified. Thus, this short review aims to present the most important applications of FD in investigating the clinical-pathological spectrum of neurodegenerative diseases.

Clinical and Morphological Study of Cervical Squamous Intraepithelial Lesions.

Squamous intraepithelial lesions (SILs) are cancer precursors targeted by secondary prevention of cervical cancer programs that are sometimes difficult to grade accurately. Mena is an actin regulatory protein involved in membrane protrusion, cell motility, in tumor invasion and metastasis. We studied retrospectively 68 cases of patients diagnosed with squamous intraepithelial lesions that received expedited treatment (treatment without colposcopic biopsy). We analyzed demographic, behavioral data, obstetrical and medical history, from the patients' medical charts and we studied the cervical fragments or cones harvested after the excisional procedure. Our study failed to identify a correlation between SILs and risk factors such as low socioeconomic status, combined oral contraceptive use, intrauterine device use, parity, gravity, except for the tobacco smoking habit that proved to be related to the cervical lesions' development. Mena was expressed in most of the analyzed SILs and its expression was correlated with lesions' grade in terms of both area and intensity, suggesting that Mena stains especially abnormal cells and that its expression intensity correlates with the risk of malignant transformation. Further studies are needed to validate Mena as an early stage of cervical carcinogenesis marker.

Assessment of tumoral and peritumoral inflammatory reaction in cutaneous malignant melanomas.

Skin cancer is one of the most common types of cancer, with an increasing worldwide incidence in recent decades. The main risk factor for increasing the skin cancer incidence is ultraviolet (UV) radiation. Of the two major forms of skin cancer (melanomas and non-melanotic cancers), the cutaneous melanoma (CM) is the most aggressive form, causing about 80% of the deaths resulted from this type of tumor. Malignant melanoma develops through malignant transformation of melanocytes in the skin because of prolonged exposure to solar or artificial UV. The malignant transformation of the melanocytes in the skin is accompanied by the presence of a local inflammatory reaction that, in the initial stages of carcinogenesis, would oppose to tumor development. Chronic exposure to UV or other etiopathogenic factors induces chronic inflammation, which, by producing inflammatory molecules (cytokines, chemokines, prostaglandins), constitutes a tumoral microenvironment that favors carcinogenesis, tumor invasion, metastasis, and the presence of neoplastic "mutant cells" that avoid the protective action of the immune system. Using immunohistochemistry techniques, we assessed the intra- and peritumoral inflammatory infiltrate cells in CM. The chronic inflammatory infiltrate presented more intense in the peritumoral stroma compared to the intratumoral one, heterogenous, more intensely composed of lymphocytes, plasma cells, macrophages, and mast cells (MCs), the most numerous cells in the inflammatory infiltrate being T-lymphocytes, plasma cells and macrophages; B-lymphocytes and MCs were in a small number, especially intratumorally. Inflammatory cells had a direct contact with tumor cells, blood vessels, connective matrix, suggesting that the inflammatory microenvironment plays an important role in carcinogenesis, tumor invasion, local angiogenesis, and tumor metastasis.

Histopathological lesions induced by stroke in the encephalon.

Strokes are conditions with a high degree of morbidity and mortality worldwide. These conditions profoundly affect the quality of life of patients; in addition to physical disabilities, patients present various mental disorders, such as mood disorders, anxiety, depression, behavioral disorders, fatigue, etc. Microscopic lesions of the brain parenchyma explain the clinical symptoms and correlate with the severity of the stroke. Our study consisted of the histopathological (HP) and immunohistochemical analysis of brain fragments, collected from 23 patients, with a clinical and imagistic diagnosis of stroke, who died during hospital admission. The microscopic analysis showed that both neurons and glial cells are affected in the ischemic focus. Neuronal death in the ischemic focus was mostly caused by cell necrosis and only about 10% by apoptosis. Regarding vascular lesions, it was observed that the most frequent HP lesion of intracerebral arterioles was arteriosclerosis. The lumen of the arterioles was reduced, and the vascular endothelium had a discontinuous aspect, which indicates a change in the blood-brain barrier. Sometimes the arteriole lumen was completely obstructed, with fibrinoid necrosis in the internal and middle tunic, or with the proliferation of fibroblasts and the formation of young intraluminal connective tissue. Intraparenchymal blood capillaries in the ischemic area showed endothelium discontinuities, lumen collapse, and sometimes massive perivascular edema. As for neuroinflammation, the presence of numerous neutrophils, lymphocytes, plasma cells and macrophages was found in the ischemic focus, forming a complex and inhomogeneous cellular mixture. Of the inflammatory cells present in the ischemic focus and in the ischemic penumbra area, the most numerous were the macrophages. The HP analysis showed that neuroinflammation is very complex and different in intensity from one patient to another, most likely due to associated comorbidities, age, treatment administered until death, etc.

Assessment of tumor microenvironment in gastric adenocarcinoma.

Gastric cancer (GC), despite the current possibilities of early diagnosis and curative treatment, remains a major public health problem, being one of the main causes of cancer, due to its detection in advanced stages. Screening programs applied in Western countries led to low incidence rates in these countries. Helicobacter pylori bacterial infection is considered to be the highest risk factor for the onset of GC because it causes chronic inflammation of the gastric mucosa and damages hydrochloric acid secretory glands, eventually leading to atrophic gastritis, which has a potential to progress to GC. In our study, we aimed at assessing the tumor microenvironment in gastric adenocarcinomas as approximately 90% of GCs are adenocarcinomas. Our study showed that the tumor microenvironment has an extremely complex morphological structure, totally different from the microscopic structure of the gastric wall, consisting of stromal cells, lymphocytes, plasma cells, macrophages, blood vessels, collagen fibers, extracellular connective matrix, other cells. The tumor microenvironment presents phenotypic, cellular and molecular heterogeneity; therefore, the microscopic aspect differs from one tumor to another and even from one region to another in the same tumor. Poorly or moderately differentiated adenocarcinomas show a more intense desmoplastic reaction than well-differentiated ones. Alpha-smooth muscle actin (α-SMA)-positive stromal cells (tumor-associated fibroblasts) and tumor macrophages were the most numerous cells of the tumor microenvironment. The tumor microenvironment is the result of cooperation between tumor cells, cancer-associated fibroblasts, immune system cells and blood vessels. It allows tumor cells to multiply, grow and metastasize.

Confirmation of Heart Malformations in Fetuses in the First Trimester Using Three-Dimensional Histologic Autopsy.

BACKGROUND: We aimed to evaluate the usefulness of three-dimensional (3D) reconstruction of histology slides to confirm congenital heart disease (CHD) detected by first-trimester fetal cardiac ultrasonography. Conventional autopsy is hindered by the small size of the first-trimester fetal heart, and current CHD confirmation studies employ the use of highly specialized and expensive methods. TECHNIQUE: An extended first-trimester ultrasound examination protocol was used to diagnose fetal heart anomalies. Medical termination of pregnancies was followed by fetal heart extraction. The specimens were sliced, and the histology slides were stained and scanned. The resulting images were processed, and volume rendering was performed using 3D reconstruction software. The volumes were analyzed by a multidisciplinary team of maternal-fetal medicine subspecialists and pathologists and compared with ultrasound examination findings. EXPERIENCE: Six fetuses with heart malformations were evaluated using histologic 3D imaging: two with hypoplastic left heart syndrome, two with atrioventricular septal defects, one with an isolated ventricular septal defect, and one with transposition of the great arteries. The technique allowed us to confirm ultrasound-detected anomalies and also identified additional malformations. CONCLUSION: After pregnancy termination or loss, histologic 3D imaging can be used to confirm the presence of fetal cardiac malformations detected during first-trimester ultrasound examination. Additionally, this technique has the potential to refine the diagnosis for counseling regarding recurrence risk and retains the advantages of standard histology.

The influence of SARS-CoV-2 on the immune system elements and on the placental structure. Clinical, histological and immunohistochemical study.

BACKGROUND: The effects of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection during pregnancy remain relatively unknown. AIM: We present this original paper where we analyzed 60 parturients, at term, 30 without associated infection (C-) and 30 with associated infection (C+), present at birth. METHODS: We analyzed the blood count and placental microscopic structure through classical and immunohistochemical staining and observed the placental areas affected by the presence of SARS-CoV-2. RESULTS: SARS-CoV-2 infection was accompanied by a decrease in the number of lymphocytes, the number of platelets and the presence of placental structural changes, identifying extensive areas of amyloid deposits, placental infarcts, vascular thrombosis, syncytial knots, with a decrease in placental vascular density and the presence of infection in the cells located at decidual level, at syncytiotrophoblast level and at the level of the cells of the chorionic plate, still without overcoming this barrier and without causing any fetal infection in the analyzed cases. CONCLUSIONS: This study shows that the invasion of SARS-CoV-2 in the placenta can produce significant structural changes, with a decrease in placental vascular density that can have significant implications on proper fetal perfusion. Also, the presence of immunoreactivity at the level of decidua, the placental villi, as well as the chorionic plate proves that the virus can overcome the maternal-fetal barrier. However, in the analyzed cases there were no fetal infections at birth, which may show that local placental factors can be a protective filter for the fetus.

Zinc-Boron-PLGA biocomposite material: preparation, structural characterization, and in vitro assessment.

Nowadays, the state-of-the-art discoveries in the field of delivery systems for therapeutic purposes have redefined the importance of biocompatible and biodegradable poly(lactic-co-glycolic acid (PLGA) nanocomposites. The study aimed to obtain a biocomposite material, with improved properties of its constituents [zinc-boron (Zn-B) complex and PLGA], by a simple, cost-effective method. The water∕oil∕water double emulsion technique allowed the adjustment of the synthesis parameters, to maximize the degree of Zn-B complex encapsulation. The morphological aspects of the samples were established by scanning electron microscopy (SEM). Particle size distribution was determined by dynamic light scattering (DLS). Morphology was typical for PLGA, spherical one. Depending on the synthesis conditions, the obtained particles have diameters between 10-450 nm. Zeta potential (ZP) showed that the particles have electronegative surface charge, offering a favorable perspective on aggregation, flocculation, and dispersion phenomena. It was observed, applying the design of experiments, that the particles size increased with increasing amounts of PLGA and polyvinyl alcohol (PVA), while ZP increased with higher PLGA and smaller PVA amounts in the formulation. The encapsulation efficiency was determined by ultra-high performance liquid chromatography∕mass spectrometry (UHPLC∕MS). The in vitro assessment was performed using Vero CCL-81 epithelial cell line and the 3-(4,5-Dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) test. Zn-B-PLGA biocomposite has promising characteristics and can be used for future biomedical applications.

Matrix metalloproteinase-9 expression in the nuclear compartment of neurons and glial cells in aging and stroke.

Matrix metalloproteinases (MMPs) are well-recognized denominators for extracellular matrix remodeling in the pathology of both ischemic and hemorrhagic strokes. Recent data on non-nervous system tissue showed intracellular and even intranuclear localizations for different MMPs, and together with this, a plethora of new functions have been proposed for these intracellular active enzymes, but are mostly related to apoptosis induction and malign transformation. In neurons and glial cells, on human tissue, animal models and cell cultures, different active MMPs have been also proven to be located in the intra-cytoplasmic or intra-nuclear compartments, with no clear-cut function. In the present study we show for the first time on human tissue the nuclear expression of MMP-9, mainly in neurons and to a lesser extent in astrocytes. We have studied ischemic and hemorrhagic stroke patients, as well as aged control patients. Age and ischemic suffering seemed to be the best predictors for an elevated MMP-9 nuclear expression, and there was no evidence of a clear-cut extracellular proteolytic activity for this compartment, as revealed by intact vascular basement membranes and assessment of vascular densities. More, the majority of the cells expressing MMP-9 in the nuclear compartment also co-expressed activated-caspase 3, indicating a possible link between nuclear MMP-9 localization and apoptosis in neuronal and glial cells following an ischemic or hemorrhagic event. These results, besides showing for the first time the nuclear localization of MMP-9 on a large series of human stroke and aged brain tissues, raise new questions regarding the unknown spectrum of the functions MMPs in human CNS pathology.

Influence of Polymer Shell Molecular Weight on Functionalized Iron Oxide Nanoparticles Morphology and In Vivo Biodistribution.

Iron oxide nanoparticles (IONPs) have been extensively used in different biomedical applications due to their biocompatibility and magnetic properties. However, different functionalization approaches have been developed to improve their time-life in the systemic circulation. Here, we have synthesized IONPs using a modified Massart method and functionalized them in situ with polyethylene glycol with different molecular weights (20 K and 35 K). The resulting nanoparticles were characterized in terms of morphology, structure, and composition using transmission electron microscopy (TEM) and selected area electron diffraction (SAED). In vivo biodistribution was evaluated in Balb/c mice, the presence of IONP being evidenced through histopathological investigations. IONP morphological characterization showed a change in shape (from spherical to rhombic) and size with molecular weight, while structural characterization proved the obtaining of highly crystalline samples of spinel structured cubic face-centered magnetite. In vivo biodistribution in a mice model proved the biocompatibility of all of the IONP samples. All NPs were cleared through the liver, spleen, and lungs, while bare IONPs were also evidenced in kidneys.

Histological and immunohistochemical study of brain damage in traumatic brain injuries in children, depending on the survival period.

Numerous studies showed that, at present, traumatic brain injury (TBI) is one of the main causes of death in young adults, but also a main cause of disabilities at all ages. For these reasons, TBI are continuously investigated. In our study, we evaluated the histopathological (HP) and immunohistochemical (IHC) changes that occurred in the brain in underage patients after a severe TBI depending on the survival period. We histopathologically and immunohistochemically analyzed a number of 22 cases of children, deceased in Dolj County, Romania, following some severe TBI, undergoing autopsy within the Institute of Forensic Medicine in Craiova between 2015-2020. Patients were divided into three groups depending on the survival period, namely: (i) patients who died during the first 24 hours of the accident; (ii) patients who died after seven days of survival; (iii) patients who died after 15 days of survival. Microscopic examinations of the brain fragments, collected during the necropsy examination, showed that the traumatic agent caused primary injuries in all brain structures (cerebral parenchyma, meninges, blood vessels). However, HP injuries ranged in size and intensity from one area to another of the brain. In patients with a longer survival period, there was observed the presence of smaller primary injuries and larger secondary injuries. There was also observed a growth in the number of meningo-cerebral microscopic injuries, depending on the increase of the survival period.

Boron-containing compounds in Dentistry: a narrative review.

Research on the use of boron (B) in the field of oral health has gained momentum in recent years, with various studies on the possibilities of using various B-containing compounds (BCCs). A multitude of applications have been discovered, from cariostatic activity to anti-inflammatory and antifungal activity, paving the way for other new research directions. B is a microelement that is commonly found in the human diet, and present throughout the body, with the highest concentration in the structure of bones, teeth, and gastrointestinal mucus gel layer. Multiple studies have demonstrated that B plays some important roles, especially in bone development and recently has been proposed to have an essential role in the healthy symbiosis. In addition, B has also attracted the interest of researchers, as various studies used BCCs in conventional or modern biomaterials. In this review, we have brought together the information we have found about B updates in the dental field and analyzing its future perspectives and potential for further studies.

Macroscopic Changes in Oral Mucosa and Hygiene Indicators in Smokers.

Smoking is the most important factor affecting the oral cavity by components born in the tobacco combustion process and acting directly on the oral mucous membranes, dental arch and indirectly on the teeth support. Recent studies show the tobacco action on the oral cavity, manifestations in the form of gingivitis, bacterial plaque, dental plaque, papillary bleeding at drilling, periodontitis. PURPOSE OF THE STUDY: In this study, we have set out to assess the macroscopic modifications of oral cavity on smokers. MATERIALS AND METHODS: The participants in the study were divided into two groups, the first group of smokers with a smoking period over 5 years and the control group of nonsmokers. The patients in the two groups underwent a physical examination and an objective clinical examination, the resulting data being compared with the control group. RESULTS: For the bacterial plaque indicatorin the smoker group there was obtained a mean value of 35.68±12.45, compared to a mean value of 16.32±6.61 for the nonsmoker group, the dental plaque indicatorfor the smoker group had a mean value of 2.24±1.02, higher than the one in the nonsmoker group, namely 0.94±0.68, and for the drilling bleeding indicator we obtained a mean value of 19.54±7.89 in the nonsmoker group, which is lower than that in the smoker group, namely 42.86±14.93. CONCLUSIONS: Smoking is a cause that maintains and aggravates the periodontal disease, including the risk of periodontitis, allowing the aggravation of gingivitis, considered a reversible surface inflammation of the gum mucosa which, by accumulation of dental plaque, the dental plaque accompanied by incorrect oral hygiene, favors the progression to periodontitis.