Short histological kaleidoscope - recent findings in histology. Part III.

The paper provides an overview of the current understanding of different cells' biology (e.g., keratinocytes, Paneth cells, myoepithelial cells, myofibroblasts, chondroclasts, monocytes, atrial cardiomyocytes), including their origin, structure, function, and role in disease pathogenesis, and of the latest findings in the medical literature concerning the brown adipose tissue and the juxtaoral organ of Chievitz.

Short histological kaleidoscope - recent findings in histology. Part II.

This article focuses on the latest histological knowledge in the field regarding the peripheral lymphoid system [mucosa-associated lymphoid tissue (MALT), bronchus-associated lymphoid tissue (BALT), gut-associated lymphoid tissue (GALT)], the thymus stroma, some of the various corpuscles of the human body (Hassall's corpuscles in thymus, arenaceous corpuscles in pineal gland, corpora amylacea in prostate and other locations) and Fañanas glial cells in the cerebellum.

Short histological kaleidoscope - recent findings in histology. Part I.

This article is a review of new advances in histology, concerning either classification or structure of different tissular elements (basement membrane, hemidesmosomes, urothelium, glandular epithelia, adipose tissue, astrocytes), and various organs' constituents (blood-brain barrier, human dental cementum, tubarial salivary glands, hepatic stellate cells, pineal gland, fibroblasts of renal interstitium, Leydig testicular cells, ovarian hilar cells), as well as novel biotechnological techniques (tissue engineering in angiogenesis), recently introduced.

Casting over Metal Method Used in Manufacturing Hybrid Cobalt-Chromium Dental Prosthetic Frameworks Assembles.

Cobalt-chromium (Co-Cr) alloys are the most widely used materials for removable and fixed dental prosthetic frameworks. The fitting accuracy between these components in dental prosthetic frameworks assembles (DPFAs) is largely influenced by the manufacturing method. This study presents a novel manufacturing method that combined two common techniques for obtaining one single framework: casting of Co-Cr inserts on top of parts previously manufactured by selective laser melting (SLM) of Co-Cr powder (CoM). Horizontal (n = 4) and vertical (n = 3) surfaces were microscopically analyzed (n = 770 count sum). The results revealed a high precision of the process and high fitting accuracy between the hybrid frameworks. The average distance measured between the frameworks in joined position was 41.08 ± 7.56 µm. In conclusion, the manufacturing of Co-Cr alloys DPFA using the CoM method reduced the deformation of hybrid frameworks and improved the joining accuracy between them.

The pioneer use of a modified PRGF-Endoret® technique for wound healing in a hemodialyzed diabetic patient in a terminal stage of renal disease.

In the literature, this paper is the first to describe the use of plasma rich in growth factors (PRGF)-Endoret® in hemodialyzed diabetic patients, to promote the healing of after amputation wounds. The PRGF-Endoret® was primarily conceived to be used in maxillofacial surgery, oral implantology, etc., the innovation residing in the blood collection technique (quantity, moment of the week, rhythmicity), which was adapted to the specific conditions of the hemodialyzed patient. Moreover, in the initial phases, the two PRGF fractions were innovatively applied as single alternating layers on the wound surface. Only after the surface of the wound decreased, the two PRGF fractions were applied as overlapping layers. Nevertheless, the paper presents the optimal method to assess the clinical evolution of the wound. Histopathological examination of the biopsy performed during wound preparation for PRGF application brought additional, essential data for orienting the therapeutic approach. The exclusion of calciphylaxis, a disease with high mortality risk, encouraged the application of this method, and also demonstrated the microscopic features in hemodialyzed diabetic patients.

Assessment of mismatch repair deficiency, CDX2, beta-catenin and E-cadherin expression in colon cancer: molecular characteristics and impact on prognosis and survival - an immunohistochemical study.

Microsatellite instability (MSI) or the deficiency of mismatch repair (MMR) proteins is one of the molecular pathways of colorectal tumorigenesis and may have important clinical implications in predicting the treatment response. We evaluated the relationship between clinicopathological features and MMR proteins [mutL homologue 1 (MLH1), mutS homologue 2 (MSH2), mutS homologue 6 (MSH6), postmeiotic segregation increased 2 (PMS2)], adhesion molecules (E-cadherin, beta-catenin) and caudal-type homeobox 2 (CDX2) in 31 patients with colon adenocarcinoma, using immunohistochemistry. We also aimed to assess the prognostic value of the studied proteins. MLH1 loss was correlated to PMS2 loss (p=0.006) and MSH2 loss (p=0.023); MSH2 loss was significantly associated to MSH6 loss (p=0.011). Tumors with MSH6 loss, together with tumors with PMS2 loss, covered all the patients with MSI status. We found a significant correlation between MSI tumors and mucinous histological type (p=0.03), but no significant associations with other clinicopathological features or with survival rate. There was a significant correlation between E-cadherin expression and differentiation degree (p=0.018) and between beta-catenin expression and lymph node invasion (p=0.046). No significant association between CDX2 loss and any clinical or pathological features was found (p>0.05). No significant differences were identified in overall survival according to E-cadherin, beta-catenin or CDX2 expression (p>0.05). In our study, PMS2 loss was significantly correlated with CDX2 loss (p=0.03). In conclusion, the molecular analysis of biological markers for colon cancer may be important for patient stratification, in order to select the optimal treatment algorithm. Our results suggest that probably the double panel (MSH6 and PMS2) is enough to detect the MSI status, instead of using the quadruple panel.

Successful management of spontaneous bone regeneration after jaws cystectomy using PRGF approach; case series.

In the jaws, the healing process of bone defects occurs differently compared with other anatomical sites where healing is done by the formation of scar tissue. This is due to physiological bone remodeling and continuous bone resorption and apposition. In the case of large cysts, there is an increased risk of postoperative infection due to the retraction of the blood clot on the bony walls. The use of plasma rich in growth factors (PRGF), with or without autologous bone addition, for filling the cystic cavities is beneficial not only for its antimicrobial effect, but also due to simultaneously release of growth factors from platelet alpha granules and adhesive proteins. The aim of our work was to emphasize the spontaneous bone healing of the maxilla and mandible after the enucleation of large and medium-sized cysts in asymptomatic patients of different age. The outcome of three patients who underwent surgery for removal of radicular cysts is presented. Imagistic [cone-beam computed tomography (CBCT)] and histological examination was performed aiming to evaluate the quality of new bone at the site of the bone defect, after different time intervals. By using PRGF approach, the healing of mandibular bone occurred 18 months after cystectomy in a smoker patient, 54-year-old, while the healing of maxillary bone using autologous bone mixed with PRGF occurred after six months in a 63-year-old patient. In a young patient (14 years old), the regeneration period was six months, using PRGF and a fibrin cloth for filling the defect.

State of the art in human adipose stem cells and their role in therapy.

Nowadays, adipose tissue appears to be the most valuable source in regenerative cell therapy, due to the following characteristics: high accessibility, high expression in a large number of individuals, high self-renewal and ability to differentiate, and hematopoietic support to the implant area. Its therapeutic potential has been experimentally observed in a broad spectrum of diseases with high population impact: diabetes, myocardial infarction, Parkinson disease, bone fractures, facial reconstruction or loss of subcutaneous tissue due to congenital abnormalities (e.g., hemifacial microsomy), trauma, burns, and tumors. Over 130 clinical trials using adipose-derived stem cells (ASCs), majority phase I or phase II, have been registered with the National Institutes of Health (NIH), and in the short term no adverse reactions or significant risks were identified. Parallel with regulatory frameworks that control their safety and assess their efficacy, phase III trials are being developed. Although transplantation with adipose tissue is becoming more and more popular, there are still important drawbacks and technical challenges to be addressed, and clinical strategies to be developed. This review explores in a concise manner the present body of knowledge concerning ASCs and their implication in therapy.

Two case reports of vertical and horizontal augmentation with autogenous bone blocks; seven years follow-up.

The current very high success rate of dental implants osseointegration has led to patients having increasingly high expectations in regards to aesthetic outcomes; therefore, effective management of soft tissues and healing of attached gingiva and papillae are essential in the effort to obtain satisfying aesthetic results for the patient. Obtaining papillae to address aesthetic requirements cannot be accomplished without bone reconstruction; an adequate volume of bone is essential in providing necessary long-term dimensional stability. The aim of this work was to highlight the advantages of autogenous bone grafting combined with plasma rich in growth factors (PRGF) in order to improve healing and reduce dehiscence risks. Two clinical cases were presented, both with important (horizontal and vertical) bone loss: in the first case, bone augmentation was performed at the same time as tooth extraction with no surgery needed for reconstruction of dental papillae, keratinized and attached mucosa; in the second case, vertical augmentation was performed by placing the bone graft in contact with an uninfected tooth. In both cases, aesthetic outcomes were as desired at the completion of treatment and also satisfactory at seven years follow-up.

Diagnostic and therapeutic approaches in oral cavity granulomas based on new data concerning their origin and pathogenesis.

Giant cell granulomas in the oral cavity are reactive hyperplastic lesions that arise either peripherally in the mucoperiosteum or centrally in the bone. The peripheral giant cell granuloma (PGCG) is a benign lesion induced by local chronic irritation. It may develop at any age, and tends to be more frequent in females. Central giant cell granuloma (CGCG) is a reactive lesion of unknown etiology. It commonly occurs in children and young adults. It is also predominant in females and frequently located in the anterior part of the mandible. Histologically, PGCG and CGCG have similar features. The lesions are non-encapsulated proliferations of oval and spindle-shaped mononuclear cells (MCs) and multiple multinucleated giant cells (MGCs) in a vascular supporting stromal tissue, associated with foci of hemorrhage. Despite the similar microscopic features, PGCG and CGCG have different clinical behavior. PGCG is usually reduced in size and asymptomatic. It grows locally, as an exophytic lesion on the alveolar mucosa, but may become slightly infiltrative in the underlying periosteum and bone. After complete excision and curettage, it has a low recurrence rate. Contrarily, CGCG has an aggressive behavior, with rapid growth and intense osteolytic activity causing perforation of the cortical plate, teeth malposition and pain. Moreover, it is characterized by a high recurrence rate. This review focuses on the origin and activating pathways of MCs and MGCs, discusses the mechanisms underlying their biological activity, tries to explain the variable clinical behavior and proposes therapeutic approaches for the granulomas associated with the jaw bones.

Vascular endothelial growth factor (VEGF) - key factor in normal and pathological angiogenesis.

Vascular endothelial growth factor (VEGF) represents a growth factor with important pro-angiogenic activity, having a mitogenic and an anti-apoptotic effect on endothelial cells, increasing the vascular permeability, promoting cell migration, etc. Due to these effects, it actively contributes in regulating the normal and pathological angiogenic processes. In humans, the VEGF family is composed of several members: VEGF-A (which has different isoforms), VEGF-B, VEGF-C, VEGF-D, VEGF-E (viral VEGF), VEGF-F (snake venom VEGF), placenta growth factor (PlGF), and, recently, to this family has been added endocrine gland-derived vascular endothelial growth factor (EG-VEGF). VEGF binds to tyrosine kinase cell receptors (VEGFRs): VEGFR-1 [Fms-like tyrosine kinase 1 (Flt-1)], VEGFR-2 [kinase insert domain receptor (KDR) in human; fetal liver kinase 1 (Flk-1) in mouse] and VEGFR-3 [Fms-like tyrosine kinase 4 (Flt-4)]. While VEGFR-1 and VEGFR-2 are expressed predominantly on vascular endothelial cells, VEGFR-3 is expressed especially on lymphatic endothelial cells. VEGFR-2 has the strongest pro-angiogenic activity and a higher tyrosine kinase activity than VEGFR-1. Endothelial cells also express co-receptors, such as neuropilin-1 (NP-1) and neuropilin-2 (NP-2), which modulate tyrosine kinase receptor activity. Both VEGF and VEGFRs are expressed not only on endothelial cells, but also on non-endothelial cells. This article aims to highlight the most recent data referring to the VEGF family and its receptors, as well as its implications in the angiogenesis process. At present, blocking angiogenesis in cancer or in other pathological processes, using anti-VEGF and anti-VEGFRs therapies, is considered to be extremely important.

The effect of plasma rich in growth factors in bone augmentation after sinus lift complications: a case report.

The case report describes a sinus membrane elevation procedure, where the augmentation was performed exclusively with plasma rich in growth factors (PRGF) and fibrin clot, followed by osseous regeneration at eight months. The patient exhibited a marked osseous atrophy in the premolar-molar area of the left superior alveolar process. Initially, we performed a sinus membrane elevation, with autologous bone on the sinus floor and bovine bone, followed by horizontal augmentation with autologous bone harvested from the mandibular ramus. The fragments were covered with PRGF and fibrin clot. Implants were inserted six months post-intervention, but due to the insertion high speed, a vestibular abscess occurred three months later. The implants and sinus graft were removed; after curettage, the sinus was filled with PRGF and fibrin clot. Eight months later, we observed the bone regeneration and the implants were reinserted. Along with implant insertion, bone was harvested for histological examination. Microscopically, the bone formation was revealed in the sinus, with differences between crestal and apical zones. The bone remodeling process was more advanced in the crestal zone compared with the apical zone. Bone regeneration was complete, and the bone density allowed the implant insertion with appropriate primary stability. Four months after implant insertion, the panoramic radiography and cone-beam computed tomography (CBCT) confirmed the implant osseointegration. Results obtained after using PRGF and fibrin clot alone as osseous addition materials in sinus lifting are highly promising, but in order to draw scientifically reasoned conclusions, further clinical studies are required.

Could oral cytomorphometry be of value in distinguishing diabetes mellitus?

The present study refers to a quantitative, morphometric analysis of exfoliative cytology smears collected from diabetes mellitus (DM) patients, in order to distinguish subtle changes in cellular and nuclear parameters. The study was carried out on 30 adult subjects: a control group of 10 healthy subjects and a study group of 20 diabetic subjects (type 1 and type 2 DM). Another factor that was taken into consideration was the abundance of the microbial flora. The oral smears were stained using Hematoxylin and Eosin and several parameters were measured (nuclear diameter, perimeter and area, cell large diameter and area), and calculated: nuclear/cytoplasmic ratio and nuclear roundness factor. We found out that the cells collected from DM patients had higher values of the nuclear parameters (the nuclei were larger) and lower cell dimensions. The nuclear to cytoplasmic ratio was increased in these patients, but the nuclear roundness factor was closer to one in the study group. Also, an increased number of bacteria, often seen in DM patients, decreased the nuclear parameters. Our findings complete recently descriptive cytology studies with the morphological measurements in case of bacterial abundance and sustain the possible value as screening method for morphometry.

Assessment of the correlations between nicotine dependence, exhaled carbon monoxide levels and oral hygiene status: an observational study.

BACKGROUND AND AIM: Cigarette smoking has negative effects on general health, including oral health. The aim of our study was to assess the correlations between nicotine dependence, exhaled carbon monoxide levels and oral hygiene status. METHODS: Smoker and non-smoker participants were enrolled in this observational study. The Fagerström test was used to classify nicotine dependences: low (score: 0-3), medium (score: 4-6) or high (score: 7-10). The oral hygiene status was classified according to the oral hygiene indices of plaque, calculus and gingival inflammation. Lastly, the exhaled carbon monoxide levels were measured with a MicroSmokelyzer (Bedfont Scientific Ltd., Kent, United Kingdom). RESULTS: Sixty five participants (50 smokers in the study group and 15 non-smokers in the control group) were enrolled between 11th and 29th of January 2016. No statistical differences were observed between the study group and the control group in terms of age (mean age±SD 23.5±1.9 and 24.0±1.5, respectively) or gender (50% and 26.6%, respectively). A statistically significant difference was observed between the 2 groups in terms of plaque, (p=0.036), calculus (p=0.001) and gingival indices (p<0.001). A positive correlation was found between the exhaled levels of carbon monoxide and the general Fagerström score (r=0.97, p<0.001) or the Fagerström score in smokers (r=0.93, p<0.001); a negative correlation was observed between the exhaled carbon monoxide levels and the number of tooth brushings daily (r=-0.41, p=0.001). The plaque index was statistically significantly associated with the exhaled carbon monoxide levels (p=0.008), general Fagerström score (p=0.016) and number of tooth brushings daily (p<0.001). The calculus and gingival indices were statistically significantly associated with the exhaled carbon monoxide levels (p<0.001), general Fagerström score (p<0.001) and score in smoker participants (p=0.029 and p=0.001, respectively) as well as the number of tooth brushings daily (p<0.001). CONCLUSION: Our study found a significant association between the plaque, calculus and gingival indices and smoking. Moreover, nicotine dependence was significantly associated with the number of daily tooth brushings and the gingival index.

Diagnostic reevaluation of 17 cases of pheochromocytoma - a retrospective study.

A rare neuroendocrine tumor, the pheochromocytoma (PCC) raises problems due both the limited experience of the researchers in this field and its pathogenic mechanisms, still not fully elucidated. The malignant potential of this tumor cannot be predicted based on its macro- or microscopic aspects, but on the presence of metastases. The aims of this study were: (1) the reevaluation of data for a pertinent and complete tumor diagnostic and prognostic pattern; (2) the statistical correlation of all investigated parameters with the malignant form and the survival rate in order to obtain a possible predictor of malignancy; (3) the potential identification of initially diagnosed benign tumors that become malignant in time. The retrospective study was conducted on 17 patients diagnosed with pheochromocytoma. We investigated: the personal data, the associated neuroendocrine syndromes, the clinical, the laboratory, the macro- and microscopic data [location, size, Hematoxylin-Eosin (HE) pheochromocytoma of the adrenal gland scaled score (PASS score), and immunohistochemical aspects] and the survival rate (analyzed by Kaplan-Meier method and Log-Rank test). The influence of diagnostic parameters on malignancy was calculated taking into consideration the survival rate. By reevaluation of the 17 cases, we tried to emphasize the value of a complex diagnosis pattern for PCCs, based on the correlation between clinical data, laboratory findings and microscopic features. A significant statistical difference between benign and malignant forms was not registered, but there were parameters as age, association with neuroendocrine syndromes, PASS score and specifically Ki-67 mitotic index that had a powerful impact on the survival rate and could be consider as possible predictors of malignancy. The potential of PCC malignant transformation was revealed in our study, by two cases that have metastasized in time.

The prognostic significance of p53, Bax, Bcl-2 and cyclin E protein overexpression in colon cancer - an immunohistochemical study using the tissue microarray technique.

In colon cancer, biological markers continue to have a limited prognostic value, the results being controversial. Studies of cell-cycle regulatory proteins and anti-apoptotic proteins aim to identify groups of patients that develop more aggressive tumors and might benefit from an individualized therapy management. The present study evaluates the prognostic role of the p53, Bax, Bcl-2 and cyclin E immunoexpression in colon cancer, using the tissue microarray (TMA) method. Tissue samples were obtained from 31 patients operated for colon cancer, embedded in TMA paraffin blocks and immunohistochemically stained for p53, Bax, Bcl-2 and cyclin E. We evaluated the relationship between the overexpression of these proteins and the clinico-pathological parameters, as well as the effect of these molecular markers on the survival rate. 65.22% of the patients were p53 positive, 39.13% Bcl-2 positive, 78.26% Bax positive and 34.78% cyclin E positive. Bcl-2(+) patients had significantly better differentiated tumors (p=0.043). Significantly poorly differentiated tumors were: Bax(+) patients (p=0.031), Bcl-2(-)÷p53(-) patients (p=0.042), Bcl-2(-)÷Bax(+) patients (p=0.029), and Bcl-2(-)÷p53(-)÷Bax(+) patients (p=0.016). The individual expression of the studied proteins did not influence the survival rate. A significantly lower survival rate was found in the following groups of patients: Bcl-2(-)÷p53(-) (40% vs. 83.3%, p=0.027), p53(-)÷Bax(+) (40% vs. 83.3%, p=0.027), Bcl-2(-)÷p53(-)÷Bax(+) (25% vs. 84.2%, p=0.003). The current study identified groups of patients with a significantly lower survival rate, which consequently are at an increased risk to develop tumors with a more aggressive biological behavior.

Role of nitro-oxidative stress in the pathogenesis of experimental rat periodontitis.

BACKGROUND AND AIMS: Periodontitis is a common chronic adult condition that implicates oxidative damage to gingival tissue, periodontal ligament and alveolar bone. This study aimed at assessing the association between the nitro-oxidative stress and the periodontal tissues destructions in experimental rat periodontitis. METHODS: Periodontitis was induced in 15 male albino rats by repetitive lesions to the gingiva adjacent to the inferior incisors, performed daily, for 16 days. On D1, D3, D6, D8, and D16 the onset and evolution of periodontitis were monitored by clinical and histopathological examinations; blood was collected and serum nitro-oxidative stress was evaluated through total nitrites and nitrates, total oxidative status, total antioxidant capacity, and oxidative stress index. RESULTS: The results demonstrated that there was a graded and continuous increase in serum levels of total nitrites and nitrates, total oxidative status and oxidative stress index, which was consistent with the severity of periodontal destructions during periodontitis progression. However, total antioxidant capacity was not significantly influenced by the disease progression. CONCLUSIONS: In experimental rat periodontitis, the systemic nitro-oxidative stress was associated with the severity of periodontal destructions assessed clinically and histopathologically. Therefore, systemic nitro-oxidative stress parameters might be used as diagnostic tools in periodontitis.

Orthodontic tooth movement following analgesic treatment with Aspirin and Algocalmin. An experimental study.

The objective of this study was the tracing of the effect of Aspirin and Algocalmin, two of the most frequently used analgesics after the application of orthodontic appliances, on the dental displacements, starting from the hypothesis according to whom any substance that inhibits prostaglandins' production will have as result the inhibition of the osteoclasts' activity and of the orthodontic tooth movements implicit. Twenty-four male Wistar rats, separated into three groups were used. Group I (control) included eight rats in which the orthodontic device was applied, without a subsequent administration of any analgesic; Group II - eight rats in which after the device application Aspirin was administrated; and Group III - eight animals in which Algocalmin was administrated. A histological study was completed in order to establish the size of bone areola. Average mesial displacement of the first left inferior maxillary molar 28 days after applying the orthodontic device was of 3.61±0.29 mm for the control group. The average displacement in the group in which Aspirin was administrated was 0.03 mm. In the group treated with Algocalmin, the dental displacement was of 0.19±0.08 mm. Histological examination revealed the presence of large sizes bone areola in control group (244 µm), more reduced in the group treated with Aspirin (74 µm), and intermediate in that treated with Algocalmin (127 µm). Treatments with Aspirin and Algocalmin in experimental groups, immediately after the orthodontic device application, induced a decreased dental displacement rate.

Microglia--performers of the 21st century.

At the frontier between immunology and neuroscience, microglia, the enigmatic macrophages of the brain, have generated, in recent years, increasing interest. In response to even minor pathological changes in the brain, these extremely versatile glial cells occasionally enter in an over-activating state and produce pro-inflammatory cytokines and free radicals, thereby contributing directly to neuroinflammation and various brain disorders. This review provides an analysis of the latest developments in the microglia field, considering the important new research that illustrate their involvement in brain related diseases.

The diagnostic value of immunohistochemistry and silver impregnation techniques for characterization of normal, reactive and tumoral astrocytes.

Astrocytes represent a heterogeneous population of specialized glial cells responsible not only for accomplishing various important functions in the healthy nervous tissue, but also for reacting to all types of the central nervous system diseases and trauma. GFAP immunostaining is considered to be the most accurate of the routine techniques used for identifying astrocytes; however, silver impregnation techniques, which are inexpensive and approachable, might be a reliable alternative. The present research has brought into question and tried to assess the sensitivity and specificity of these classical methods for identifying and differentiating normal and reactive from tumoral astrocytes. Our study included 10 supratentorial gliomas specimens of various grade and two normal brain samples. We performed a histological study on consecutive seriated sections labeled using four methods: the immunostaining for GFAP (glial fibrillary acidic protein) and the three silver impregnation techniques: Ramón y Cajal, Bielschowsky-Cajal and Gömöri. For each tumoral case, two areas were examined: the tumoral parenchyma and the tumor borders (considered as reactive gliosis) and were both compared to healthy brain parenchyma; for each area, three microscopic fields were assessed and two parameters were recorded: a semi-quantitative score (the astrocytes' density) and a qualitative score (the color intensity). We used a complex statistical analysis in order to process the data and to compare the diagnostic value of silver impregnation techniques versus GFAP immunostaining (the reference method) in terms of tumoral grading and differentiating tumoral from normal and reactive astrocytes. Our results indicated that there data provided by both GFAP immunostaining and silver impregnation techniques were comparable.