Cytoplasmic Projections Research Articles

Light and electron microscopy studies of siphon and siphonal sheath formation in the infaunal bivalve Tresus keenae (Bivalvia: Mactridae)

To understand the habitat ecology of Tresus keenae, an infaunal bivalve, the microanatomical structure of the siphon and the method of siphonal sheath formation were described. The diameter of the incurrent siphon was approximately 1.2 times greater than that of the excurrent siphon. Several irregular tentacles developed inside the distal end of the siphon. The tentacles in the incurrent siphon were approximately twice as long as those in the excurrent siphon. The siphon consisted of six tissue layers, which, from the outside inward, were the siphonal sheath, matrix, outer epithelial layer, connective tissue layer, muscular layer, and inner epithelial layer. The siphonal sheath was composed of an outer cuticle and dense microfilament layer and had vertical ducts. The matrix showed a loose microfilament layer. The outer epithelial layer was simple consisting of ciliated columnar epithelia and secretory cells. There were two types of secretory cells: arenophilic cells and proteinous granular cells. These were all unicellular glands, with cytoplasmic projections developing on the free surface and microstructural features of the cytoplasm showing secretory activity. Histochemical analysis indicated that the secretory granules of the secretory cells, the dense microfilament layer, and the matrix were composed of neutral carboxylated mucopolysaccharides. From these characteristics, it was concluded that the siphonal sheath was formed via the transportation of substances secreted by secretory cells of the outer epithelial layer to the outside through the duct. The hemolymph sinus developed in the connective tissue layer. The muscular layer had alternating longitudinal and circular muscle layers. The inner epithelial layer was simple and consisted of ciliated columnar epithelial cells and secretory cells. Secretory cells are goblet-like cells and contain acidic carboxylated substances. The siphonal sheath was identified starting at approximately 3.5 mm in shell length before the infaunal stage; as it grew, the siphonal sheath thickened, reflecting the infaunal habitat.

Antibacterial and Anti-inflammatory Activity of Extracts and Major Constituents Derived from Stachytarpheta indica Linn. Leaves and Their Potential Implications for Wound Healing.

Wounds of various types continue to have a severe socioeconomic impact on the cost of health care. Globally, there has been increased interest surrounding the identification of bioactive compounds that promote or modulate the wound healing process. Stachytarpheta indica Linn. is traditionally used to heal wounds and relieve inflammation; however, the theorised pharmacological properties have not yet been scientifically validated. In this study, dried and ground plant leaves were extracted with water and methanol, which were then subjected to various analyses. The antimicrobial activity of the plant extracts and isolated compounds was determined using well diffusion assays, while the minimum inhibitory concentrations were determined with a colorimetric assay. Morphological changes of human keratinocytes in response to plant extracts were observed with differential interference contrast microscope imaging. Cell viability, proliferation, and migratory effects post-treatment with the plant extracts were also evaluated via colorimetric cytotoxicity assays and a real-time cell analyser protocol. Anti-inflammatory effects of plant extracts and isolated compounds were evaluated by flow cytometry and cyclooxygenase and lipoxygenase enzyme inhibition assays. Three active compounds, i.e. ipolamiide, verbascoside and iso-verbascoside, were isolated from S. indica leaves. Verbascoside demonstrated broad-range antibacterial activity and imposed strong inhibition at 9.77μg/mL against Staphylococci spp. S. indica extracts (0.1-0.2mg/mL) were shown to improve human keratinocyte proliferation up to 60% and induce morphological changes by producing cytoplasmic projections at concentrations higher than 0.4mg/mL. Plant extracts (6.25-100μg/mL) and individual compounds (3.125-50μg/mL) elicited strong anti-inflammatory effects by suppressing the expression of interleukin-8 and inhibiting cyclooxygenase-1 and 5-lipoxygenase enzymes. Collectively, these results indicate that plant extracts and isolated compounds derived from S. indica have the potential to inhibit bacterial growth, promote tissue regeneration and reduce inflammation, hence, potentially providing the basis for a novel therapeutic for the treatment of wounds.

First study on response of astrocytes in alevines of red-bellied pacu (Piaractus brachypomus) to subchronic exposure to chlorpyrifos and trichlorfon.

Background and Aim:Organophosphate pesticides (OPs) used in agricultural production pose environmental and public health risks whenever non-target organisms are exposed to them. Oxon-type OPs, such as trichlorfon (TCF) and chlorpyrifos (CPF), are frequently used in Colombia and have been detected in water bodies in the vicinity of croplands; however, their effect on aquatic organisms, especially fish, is largely unknown. The neurotoxicity of OPs includes inhibition of esterase enzymes, neuronal damage, and increased glial reactivity. This study aimed to assess the astrocytic response in the brain tissue of juvenile red-bellied pacu (Piaractus brachypomus) exposed to TCF and CPF.Materials and Methods:A 25-day subchronic assay was conducted in which juvenile red-bellied pacu were exposed to CPF and TCF. After 25 days of exposure, the fish were killed and brain samples were collected and processed for immunohistochemistry to assess the morphology and reactivity of astrocytes; glial acidic fibrillary protein was used as a biomarker.Results:The brain samples from animals under subchronic exposure to OPs for 25 days showed higher cellular density as well as changes in astrocyte phenotype characterized by shortening of cytoplasmic projections, hypertrophy, and ameboid morphology compared to those from nonexposed animals. Similarly, astrocyte hyperreactivity was detected in the optic tectum and medial longitudinal fasciculus of the exposed group.Conclusion:Immunoreactivity of brain glial cells under subchronic exposure to OPs measured through immunohistochemical tests as well as OPs-induced neuropathology may be useful as a biomarker for monitoring environmental pollution. The results also indicate that P. brachypomus is a suitable biomonitoring model for studying neurotoxicological and neurodegenerative diseases.

Exploring Honeybee Abdominal Anatomy through Micro-CT and Novel Multi-Staining Approaches.

Simple SummaryApis mellifera or western honeybees are insects belonging to the Order Hymenoptera and the most important pollinators worldwide with great implications in natural biodiversity and agriculture due to their importance in pollination and honey production. The characterization of honeybee anatomy with precise tools will allow a better comprehension of the physiology of these insects under different biological conditions. Here, we employed Micro-computed tomography and novel staining methods to define the morphoanatomical characteristics of the worker honeybee abdomen. We defined the 3D and 2Ds structures of the midgut and hindgut and discovered a new cell type called ventricular telocyte, with possible roles in honeybee epithelium maintenance. Overall, we propose that this method will be useful for further investigation of the structure of the honeybee abdomen under a wide variety of environmental conditions.Continuous improvements in morphological and histochemical analyses of Apis mellifera could improve our understanding of the anatomy and physiology of these insects at both the cellular and tissue level. In this work, two different approaches have been performed to add new data on the abdomen of worker bees: (i) Micro-computed tomography (Micro-CT), which allows the identification of small-scale structures (micrometers) with adequate/optimal resolution and avoids sample damage and, (ii) histochemical multi-staining with Periodic Acid-Schiff-Alcian blue, Lactophenol-Saphranin O and pentachrome staining to precisely characterize the histological structures of the midgut and hindgut. Micro-CT allowed high-resolution imaging of anatomical structures of the honeybee abdomen with particular emphasis on the proventriculus and pyloric valves, as well as the connection of the sting apparatus with the terminal abdominal ganglia. Furthermore, the histochemical analyses have allowed for the first-time description of ventricular telocytes in honeybees, a cell type located underneath the midgut epithelium characterized by thin and long cytoplasmic projections called telopodes. Overall, the analysis of these images could help the detailed anatomical description of the cryptic structures of honeybees and also the characterization of changes due to abiotic or biotic stress conditions.

Pulmonary damage in a patient with hairy cell leukemia - infectious involvement or hematological disease activity? Case report.

Hairy cell leukemia (HCL) is a rare indolent lymphoproliferative disease with an accumulation of mature B lymphocytes with fine reticular chromatin and cytoplasm with typical hairy-like cytoplasmic projections. Rarely, hairy cell leukemia manifests as a lung infiltration. The differential diagnosis between infection and malignant involvement with hairy cell leukemia is often challenging in such situations. We present a 53-year-old female with an uncommon pulmonary involvement with hairy cell leukemia. In addition, we discuss the complicated differential diagnosis of pulmonary disease in patients with hairy cell leukemia and the treatment approach to these patients. This case report describes the successful therapy management of a patient with pulmonary involvement by hairy cell leukemia. Therapy with interferon-alfa and cladribine resulted in long-term remission of the underlying disease.

An injury-responsive Rac-to-Rho GTPase switch drives activation of muscle stem cells through rapid cytoskeletal remodeling.

Many tissues harbor quiescent stem cells that are activated upon injury, subsequently proliferating and differentiating to repair tissue damage. Mechanisms by which stem cells sense injury and transition from quiescence to activation, however, remain largely unknown. Resident skeletal muscle stem cells (MuSCs) are essential orchestrators of muscle regeneration and repair. Here, with a combination of invivo and exvivo approaches, we show that quiescent MuSCs have elaborate, Rac GTPase-promoted cytoplasmic projections that respond to injury via the upregulation of Rho/ROCK signaling, facilitating projection retraction and driving downstream activation events. These early events involve rapid cytoskeletal rearrangements and occur independently of exogenous growth factors. This mechanism is conserved across a broad range of MuSC activation models, including injury, disease, and genetic loss of quiescence. Our results redefine MuSC activation and present a central mechanism by which quiescent stem cells initiate responses to injury.

Novel insights into the BAP1-inactivated melanocytic tumor

BAP1-inactivated melanocytic tumor (BIMT) is a group of melanocytic neoplasms with epithelioid cell morphology molecularly characterized by the loss of function of BAP1, a tumor suppressor gene located on chromosome 3p21, and a mutually exclusive mitogenic driver mutation, more commonly BRAF. BIMTs can occur as a sporadic lesion or, less commonly, in the setting of an autosomal dominant cancer susceptibility syndrome caused by a BAP1 germline inactivating mutation. Owing to the frequent identification of remnants of a conventional nevus, BIMTs are currently classified within the group of combined melanocytic nevi. “Pure” lesions can also be observed. We studied 50 BIMTs from 36 patients. Most lesions were composed of epithelioid melanocytes of varying size and shapes, resulting extreme cytomorphological heterogeneity. Several distinctive morphological variants of multinucleated/giant cells were identified. Some hitherto underrecognized microscopic features, especially regarding nuclear characteristics included nuclear blebbing, nuclear budding, micronuclei, shadow nuclei, peculiar cytoplasmic projections (ant-bear cells) often containing micronuclei and cell-in-cell structures (entosis). In addition, there were mixed nests of conventional and BAP1-inactivated melanocytes and squeezed remnants of the original nevus. Of the 26 lesions studied, 24 yielded a BRAF mutation, while in the remaining two cases there was a RAF1 fusion. BAP1 biallelic and singe allele mutations were found in 4/22 and 16/24 neoplasms, respectively. In five patients, there was a BAP1 germline mutation. Six novel, previously unreported BAP1 mutations have been identified. BAP1 heterozygous loss was detected in 11/22 lesions. Fluorescence in situ hybridization for copy number changes revealed a related amplification of both RREB1 and MYC genes in one tumor, whereas the remaining 20 lesions studied were negative; no TERT-p mutation was found in 14 studied neoplasms. Tetraploidy was identified in 5/21 BIMTs. Of the 21 patients with available follow-up, only one child had a locoregional lymph node metastasis. Our results support a progression of BIMTs from a conventional BRAF mutated in which the original nevus is gradually replaced by epithelioid BAP1-inactivated melanocytes. Some features suggest more complex underlying pathophysiological events that need to be elucidated.

The Ism between Endothelial Cilia and Endothelial Nanotubules Is an Evolving Concept in the Genesis of the BBB.

The blood–brain barrier (BBB) is fundamental in maintaining central nervous system (CNS) homeostasis by regulating the chemical environment of the underlying brain parenchyma. Brain endothelial cells (BECs) constitute the anatomical and functional basis of the BBB. Communication between adjacent BECs is critical for establishing BBB integrity, and knowledge of its nanoscopic landscape will contribute to our understanding of how juxtaposed zones of tight-junction protein interactions between BECs are aligned. The review discusses and critiques types of nanostructures contributing to the process of BBB genesis. We further critically evaluate earlier findings in light of novel high-resolution electron microscopy descriptions of nanoscopic tubules. One such phenotypic structure is BEC cytoplasmic projections, which, early in the literature, is postulated as brain capillary endothelial cilia, and is evaluated and compared to the recently discovered nanotubules (NTs) formed in the paracellular spaces between BECs during barrier-genesis. The review attempts to elucidate a myriad of unique topographical ultrastructures that have been reported to be associated with the development of the BBB, viz., structures ranging from cilia to BEC tunneling nanotubules (TUNTs) and BEC tethering nanotubules (TENTs).

SARS-CoV-2: Ultrastructural Characterization of Morphogenesis in an In Vitro System.

The pandemic caused by the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has impacted public health and the world economy and fueled a worldwide race to approve therapeutic and prophylactic agents, but so far there are no specific antiviral drugs. Understanding the biology of the virus is the first step in structuring strategies to combat it, and in this context several studies have been conducted with the aim of understanding the replication mechanism of SARS-CoV-2 in vitro systems. In this work, studies using transmission and scanning electron microscopy and 3D electron microscopy modeling were performed with the goal of characterizing the morphogenesis of SARS-CoV-2 in Vero-E6 cells. Several ultrastructural changes were observed—such as syncytia formation, cytoplasmic membrane projections, lipid droplets accumulation, proliferation of double-membrane vesicles derived from the rough endoplasmic reticulum, and alteration of mitochondria. The entry of the virus into cells occurred through endocytosis. Viral particles were observed attached to the cell membrane and in various cellular compartments, and extrusion of viral progeny took place by exocytosis. These findings allow us to infer that Vero-E6 cells are highly susceptible to SARS-CoV-2 infection as described in the literature and their replication cycle is similar to that described with SARS-CoV and MERS-CoV in vitro models.

Why Human Prepuce is a Valuable Resource in Science? Histological, Ultrastructural, Immunohistochemical and Statistical Analysis

This research was to examine the histological and ultrastructural characteristics of prepuce samples, as well as vimentin and S100 protein localization and statistical analysis. Urologists have long struggled with the prepuce, which is used to treat a variety of urethral problems. Skin biopsies were collected from the prepuce at the moment of circumcision and processed for light microscopy, electron microscope examination, immunohistochemical techniques, and statistical analysis in a total of six boys. Histologically, the prepuce epidermis displayed focal spiky ridges, which are saw-toothed interspersed with sulci, slight hyperpigmentation, looser connective tissue and plentiful vascular components. Immunohistochemically, the existence of melanocytes and Langerhans cells in the epidermis, as well as smooth muscles in the dermis, was stained positively for vimentin. Also, there was a positive reactivity of the Langerhans cells in the epidermis and around Meissner's corpuscles in the dermis for S100 protein staining. Ultrastructurally, the prepuce's intercellular gaps were widened, melanocytes rested on a folded basement membrane, and desmosomal content was reduced, with a prominent active euchromatic nucleus. Cytoplasmic projections were distended and elongated, and the interstitial blood vessels were surrounded by endothelial cells and rested on a basement membrane. There were also minimal collagen fibers in the interstitium. The prepuce's histological and ultrastructural features, as well as immunohistological studies using vimentin and S100 protein as intermediate filaments and statistical analysis, all demonstrated that it is a useful scientific resource.

Telocytes: Active Players in the Rainbow Trout (Oncorhynchus mykiss) Intestinal Stem-Cell Niche.

Simple SummaryAquaculture is expanding due to the high demand of fish for human consumption. However, since carnivorous fish are fed using fish-derived proteins and lipids, the sustainability of this food-producing sector is debated. Therefore, feed industries and academia are dedicating their efforts to the search for suitable raw materials and more sustainable alternative feeds that are able to ensure the health of the fish. To properly evaluate the effect of these feed formulations, extensive knowledge of the intestinal morphology and physiology is required. Moreover, the intestine is a dynamic environment in which homeostasis is controlled by highly specialized intestinal stem-cell niches. These defined functional units consist of epithelial stem cells, the supportive mesenchymal cell population, and acellular components. While they have been widely studied in the mouse intestine, this understanding is almost absent in fish species. We have previously characterized the organization of the stem-cell niche in the rainbow trout intestine; here, we expand that knowledge by examining telocytes as active stromal components of the niche. Our results indicate that this cell type is also present in rainbow trout and that it represents a key mediator of intestinal homeostasis by virtue of its active interaction with the stem cells.In order to improve the sustainability of trout farming, it is essential to develop alternatives to fish-based meals that prevent intestinal disorders and support growth performances. Therefore, an accurate knowledge of intestinal morphology and physiology is desirable. We previously described the epithelial component of the intestinal stem-cell (ISC) niche in rainbow trout (Oncorhynchus mykiss), which is one of the most successfully farmed species and a representative model of the salmonids family. This work aims to expand that knowledge by investigating the niche stromal components that contribute to intestinal homeostasis. We analyzed samples belonging to five individuals collected from a local commercial farm. Histological and ultrastructural studies revealed peculiar mesenchymal cells adjacent to the epithelium that generated an intricate mesh spanning from the folds’ base to their apex. Their voluminous nuclei, limited cytoplasm and long cytoplasmic projections characterized them as telocytes (TCs). TEM analysis showed the secretion of extracellular vesicles, suggesting their functional implication in cell-to-cell communication. Furthermore, we evaluated the localization of well-defined mouse TC markers (pdgfrα and foxl1) and their relationship with the epithelial component of the niche. TCs establish a direct connection with ISCs and provide short-range signaling, which also indicates their key role as the mesenchymal component of the stem-cell niche in this species. Interestingly, the TC distribution and gene-expression pattern in rainbow trout closely overlapped with those observed in mice, indicating that they have the same functions in both species. These results substantially improve our understanding of the mechanisms regulating intestinal homeostasis and will enable a more detailed evaluation of innovative feed effects.

BRAF V600E Positive Hairy Plasma Cell Leukemia; Are the Cytoplasmic Projections in Plasma Cells Predictive of a Particular Molecular Characterization?

Introduction: Plasma cell leukemia (PCL) is a rare and clinically aggressive form of plasma cell dyscrasia. Despite the significant role of BRAF mutation in plasma cell neoplasms, this mutation has been rarely considered in these cases. Finding evidence guiding us toward assessing the BRAF mutation in patients with plasma cell neoplasms could help make the suitable decision for targeted therapy. Case Presentation: A 79-year-old man presented with leukocytosis. Peripheral blood smear exhibited marked lymphocytosis and infiltration of about 50% abnormal lymphoid cells with slender cell-surface projections and oval shape nucleus. These findings raised the provisional diagnosis of hairy cell leukemia (HCL) or HCL variants (HCL-v). Molecular analysis confirmed the presence of BRAFV600E mutation, which was in agreement with HCL diagnosis, albeit the flow cytometric assessment of abnormal lymphocytes corroborated PCL. Conclusions: Together with the previous comprehensive analysis regarding the association of cytoplasmic projections and BRAF mutations, our findings could suggest this morphological characteristic in plasma cells (PCs) as an indication for the assessment of BRAF V600E mutation in PC dyscrasias.

The ultrastructure of spermatogenic cells and morphological evaluation of testicular development in the silver pomfret (Pampus argenteus).

The silver pomfret (Pampus argenteus) is a widely distributed and economically important marine fish in the Indo-Pacific. In this study, we acquired the second generation of wild P.argenteus by artificial breeding and further studied the testicular development and ultrastructure of spermatogenesis. The results of gonadosomatic index (GSI) showed the spawning period of this marine fish was from April to June. Besides, through morphological analysis, we found that P.argenteus had an anastomosing tubular testis surrounded by a layer of tunica albuginea, in which spermatogenesis occurred in cysts where the synchronous germ cells were completely surrounded by the cytoplasmic projection of Sertoli cells. Meanwhile, based on submicroscopic characteristics, the germ cells are classified into nine different types. During the ontogenesis of testis, both the early stage of spermatogenesis and sperm were observed in P.argenteus. At sperm maturation stage, different types of spermatozoa and activation of sperms occurred non-synchronously in the tubules. Cytoplasmic bridges also were observed among synchronous germ cells within the cysts, suggesting an interrelated and differentiated relationship among these germ cells.

Cardiac Telocytes 16 Years on-What Have We Learned So Far, and How Close Are We to Routine Application of the Knowledge in Cardiovascular Regenerative Medicine?

The regeneration of a diseased heart is one of the principal challenges of modern cardiovascular medicine. There has been ongoing research on stem-cell-based therapeutic approaches. A cell population called telocytes (TCs) described only 16 years ago largely contributed to the research area of cardiovascular regeneration. TCs are cells with small bodies and extremely long cytoplasmic projections called telopodes, described in all layers of the heart wall. Their functions include cell-to-cell signaling, stem-cell nursing, mechanical support, and immunoregulation, to name but a few. The functional derangement or quantitative loss of TCs has been implicated in the pathogenesis of myocardial infarction, heart failure, arrhythmias, and many other conditions. The exact pathomechanisms are still unknown, but the loss of regulative, integrative, and nursing functions of TCs may provide important clues. Therefore, a viable avenue in the future modern management of these conditions is TC-based cell therapy. TCs have been previously transplanted into a mouse model of myocardial infarction with promising results. Tandem transplantation with stem cells may provide additional benefit; however, many underresearched areas need to be addressed in future research before routine application of TC-based cell therapy in human subjects. These include the standardization of protocols for isolation, cultivation, and transplantation, quantitative optimization of TC transplants, cost-effectivity analysis, and many others.

Seminoma e sertolioma em cão não criptorquida – relato de caso

The most common testicular neoplasms in dogs are seminoma, leydigocytoma and sertolioma, affecting middle--aged and elderly dogs, where cryptorchidism is a predisposing factor, as well as some breeds. It can occur alone or, less fren-quently, concurrently, generally affecting the same testicle. This study aimed to report the case of a non-cryptorchid 14-year--old mixed breed dog diagnosed with seminoma and sertolioma, each in a testicle. The animal showed an increase in scrotal volume, with no changes in other clinical parameters on physical examination. On ultrasound examination, it was possible to observe alterations suggestive of neoplasia in both testicles and prostatic alteration suggestive of benign prostatic hyperplasia. Complementary blood count and biochemical tests were performed and, as treatment, orchiectomy was performed. Fragments were collected from both testicles and sent for histopathological examination. Microscopy of the left testicle showed the presence of round cells, multiple and evident nucleoli, cells in different phases of mitosis and binucleation, these changes being compa-tible with seminoma. In contrast, in the right testicle, spindle and elongated cells (pseudo-lobular) were observed, presence of long cytoplasmic projections with rounded ovoid nucleus, spindle cells and degeneration of seminiferous tubules, compatible with sertolioma. It was observed that physical examination associated with ultrasound was efficient to detect the presence of neoplasms, being validated by histopathological examination. Orchiectomy was an assertive treatment indicated for this case.

Hairy Cell Leukemia (Morphologic and Immunophenotypic Profile)

Hairy Cell Leukemia (HCL) is a lymphoproliferative B cell abnormality dominated by mature lymphocytes with cytoplasmic projections and often misunderstood as Chronic Lymphocytic Leukemia (CLL). Misdiagnosis can be caused by errors in the preparation of peripheral Blood Smear Evaluation (BSE). Immunophenotyping is an option to differentiate HCL from CLL. A 56-year-old female presented with complaints of weakness. Physical examination showed conjunctival anemia 3 3 and hepatosplenomegaly. Hematological test results were as follows: Hb 7.4 g/dL; WBC 131.24x10 /uL; and Plt 61x10 /uL. BSE And Bone Marrow Aspiration (BMA) showed predominantly mature lymphocytes with cytoplasmic projections and suspected CLL with HCL as the differential diagnosis. Immunophenotyping with peripheral blood samples showed CD19+, CD20+, CD79a+, HLA-DR+, CD5-, and CD7- suggesting an increasing mature lymphocytes population (74.16%) that expressed B lymphoid lineage. White Precursor Cell (WPC) channel test showed an abnormal lymphocytes population. The differential diagnosis of patients with dominant mature lymphocytes BSE with cytoplasmic projections was CLL and HCL. Immunophenotyping of CLL showed positive results on B cell markers (CD19, CD20, CD79a, and HLA-DR) with aberrant CD5. However, in such an HCL case like this, there were strongly positive results on B cell markers but the absence of aberrant CD5. This study was supported by the presence of abnormal lymphocytes population in the WPC test. The diagnosis of HCL in this patient was based on interpretation of BSE and immunophenotyping, supported by the WPC test.

Age-related Histological Changes in the Renal Telocytes in Male Albino Rats

Background:Many researches on telocytes (TCs) have proved its exis­tence, structure and specific immune markers expression in many normal organs and in different species. Multiple physiologic functions have been suggested for these cells. Objectives: This study is designed to evaluate age-related changes ofTCs in different age groups in the renal tissue. Materials and Methods: 18 male Sprague- Dawley rats were used in this study and divided equally into 3 groups (each consists of 6 rats); Group I (rats aged 3 weeks), Group II (rats aged 3 months, adult) and Group III (rats aged one year). All rats of group I, II and III were sacrificed and each group was divided into two subgroups. The first subgroup was processed for light microscopic and immunohistochemical staining. The second subgroup was processed for electron microscopy. Morphometric and statistical studies were conducted. Results: TCs with their characteristic long and thin cytoplasmic projections (telopodes, Tps) are detected in each of H&E stained and CD34 immunostained sections. In group III, there is a significant reduction of the TCs count. TEM examination of the ultrathin sections revealed shrinkage of TCs with disintegration and fragmentation of the Tps with a significant reduction of the number of Tps arising from each TC in group III. In all groups of the study, homocellular and heterocellular junctions are observed. Conclusion: On comparison of the age groups in the study, it is proved that TCs decrease in number with degenerative changes observed with aging.

Biological effects of sodium fluoride varnishes used in remineralisation of enamel: An in vitro study.

During the last three decades, fluoride varnishes have been recognised as effective strategies for caries prevention in the young-child population and have contributed to a decrease in its prevalence worldwide. The present study aimed to assess in vitro the level of cytotoxicity and genotoxicity in human primary pulp fibroblasts (DPFs) of two NaF varnishes. Four experimental assays were carried out (MTS, Mitotracker® system [mitochondrial function and morphology], Live/Dead®, and Comet) to assess the morphology, viability, and genotoxicity of two NaF varnishes (Duraphat® and Clinpro White®, both at two different concentrations). The essays were conducted on cultured pulp fibroblasts, grouped in four experimental and two control groups. Collected data were analysed by one-way ANOVA followed by the post hoc Bonferroni test. Some morphological changes of DPFs could be detected after the NaFVs stimulation. Most DPFs incubated in Duraphat (22.6 mg/L) maintained their morphological characteristics, except for a small decrease in cell size and shorter cytoplasmic projections (filopodia); DPFs treated with Clinpro White Varnish (22.6 mg/L) presented a morphology and size similar to the control group. DPFs exposed to Duraphat (113 mg/L) exhibited significant morphological alterations with considerable cell size increases and DPFs treated with Clinpro White Varnish (113 mg/L) showed a slight cell size increase without noticeable morphological anomalies. The Duraphat (22.6 mg/L) and Clinpro White Varnish (22.6 mg/L) groups promoted 31% and 35% cell proliferation, respectively, whereas DPFs proliferation with Duraphat (113 mg/L) decreased up to 59%, and cell proliferation with Clinpro White Varnish (113 mg/L) was similar to that of control. All tested varnishes induced changes in the fibroblastic mitochondria. In general, Duraphat was less biocompatible and caused a change in the number of mitochondria compared to Clinpro White Varnish.

Comparative evaluation of osteogenic differentiation potential of stem cells derived from dental pulp and exfoliated deciduous teeth cultured over granular hydroxyapatite based scaffold

BackgroundMesenchymal stem cells isolated from the dental pulp of primary and permanent teeth can be differentiated into different cell types including osteoblasts. This study was conducted to compare the morphology and osteogenic potential of stem cells from exfoliated deciduous teeth (SHED) and dental pulp stem cells (DPSC) in granular hydroxyapatite scaffold (gHA). Preosteoblast cells (MC3T3-E1) were used as a control group.MethodologyThe expression of stemness markers for DPSC and SHED was evaluated using reverse transcriptase-polymerase chain reaction (RT-PCR). Alkaline phosphatase assay was used to compare the osteoblastic differentiation of these cells (2D culture). Then, cells were seeded on the scaffold and incubated for 21 days. Morphology assessment using field emission scanning electron microscopy (FESEM) was done while osteogenic differentiation was detected using ALP assay (3D culture).ResultsThe morphology of cells was mononucleated, fibroblast-like shaped cells with extended cytoplasmic projection. In RT-PCR study, DPSC and SHED expressed GAPDH, CD73, CD105, and CD146 while negatively expressed CD11b, CD34 and CD45. FESEM results showed that by day 21, dental stem cells have a round like morphology which is the morphology of osteoblast as compared to day 7. The osteogenic potential using ALP assay was significantly increased (p < 0.01) in SHED as compared to DPSC and MC3T3-E1 in 2D and 3D cultures.ConclusiongHA scaffold is an optimal scaffold as it induced osteogenesis in vitro. Besides, SHED had the highest osteogenic potential making them a preferred candidate for tissue engineering in comparison with DPSC.

A Tug-of-War Model Explains the Saltatory Sperm Cell Movement in Arabidopsis thaliana Pollen Tubes by Kinesins With Calponin Homology Domain.

Upon pollination, two sperm cells are transported inside the growing pollen tube toward the apex. One sperm cell fertilizes the egg cell to form the zygote, while the other fuses with the two polar nuclei to form the triploid endosperm. In Arabidopsis thaliana, the transport of the two sperm cells is characterized by sequential forward and backward movements with intermediate pauses. Until now, it is under debate which components of the plant cytoskeleton govern this mechanism. The sperm cells are interconnected and linked to the vegetative nucleus via a cytoplasmic projection, thus forming the male germ unit. This led to the common hypothesis that the vegetative nucleus is actively transported via myosin motors along actin cables while pulling along the sperm cells as passive cargo. In this study, however, we show that upon occasional germ unit disassembly, the sperm cells are transported independently and still follow the same bidirectional movement pattern. Moreover, we found that the net movement of sperm cells results from a combination of both longer and faster runs toward the pollen tube apex. We propose that the observed saltatory movement can be explained by the function of kinesins with calponin homology domain (KCH). This subgroup of the kinesin-14 family actively links actin filaments and microtubules. Based on KCH's specific properties derived from in vitro experiments, we built a tug-of-war model that could reproduce the characteristic sperm cell movement in pollen tubes.