Peripheral Cell Layers Research Articles

Machine learning for classification of cutaneous sebaceous neoplasms: implementing decision tree model using cytological and architectural features

BackgroundThis observational study aims to describe and compare histopathological, architectural, and nuclear characteristics of sebaceous lesions and utilized these characteristics to develop a predictive classification approach using machine learning algorithms.MethodsThis cross-sectional study was conducted on Iranian patients with sebaceous tumors from two hospitals between March 2015 and March 2019. Pathology slides were reviewed by two pathologists and the architectural and cytological attributes were recorded. Multiple decision tree models were trained using 5-fold cross validation to determine the most important predictor variables and to develop a simple prediction model.ResultsThis study assessed the characteristics of 123 sebaceous tumors. Histopathological findings, including pagetoid appearance, neurovascular invasion, atypical mitosis, extensive necrotic area, poor cell differentiation, and non-lobular tumor growth pattern, as well as nuclear features, including highly irregular nuclear contour, and large nuclear size were exclusively observed in carcinomatous tumors. Among non-carcinomatous lesions, some sebaceoma and sebaceous adenoma cases had features like high mitotic activity, which can be misleading and complicate diagnosis. Based on multiple decision tree models, the five most critical variables for lesion categorization were identified as: basaloid cell count, peripheral basaloid cell layers, tumor margin, nuclear size, and chromatin.ConclusionsThis study implemented a machine learning modeling approach to help optimally categorize sebaceous lesions based on architectural and nuclear features. However, studies of larger sample sizes are needed to ensure the accuracy of our suggested predictive model.

Visible Light Optical Coherence Tomography Reveals the Relationship of the Myoid and Ellipsoid to Band 2 in Humans.

PurposeWe employ visible light optical coherence tomography (OCT) to investigate the relationship between the myoid, ellipsoid, and band 2 in the living human retina. Rather than refute existing theories, we aim to reveal new bands and better delineate the structures at hand.MethodsAn upgraded spectral/Fourier domain visible light OCT prototype, with 1.0-µm axial resolution, imaged 13 eyes of 13 young adult human subjects (23–40 years old) without a history of ocular pathology. The external limiting membrane (band 1) and band 2 edges were segmented. Reflectivity was examined along the inner segment (IS), defined as extending from band 1 to the band 2 center, and within band 2 itself.ResultsImages highlight a nearly continuously resolved extrafoveal internal limiting membrane, the peripheral single-cell thick ganglion cell layer, and the peripheral photoreceptor axonal fiber layer, a peripheral division of band 2 into bands 2a and 2b, and a reflectivity-based division of the IS into “m” and “e” zones.DiscussionTopography and transverse intensity variations of the outermost band 2b suggest an association with rods. The “m” and “e” zone border is consistent with the myoid–ellipsoid boundary, even recapitulating the well-documented distribution of mitochondria throughout the IS at the foveal center. Theories of outer retinal reflectivity in OCT must adequately explain these observations.Translational RelevanceFindings support that band 2 does partially overlap with the ellipsoid in transversally averaged OCT images due to photoreceptor IS length dispersion but argue that the inner ellipsoid must be inner to band 2, as suggested by prior quantitative measurements.

Potassium transporter TRH1/KUP4 contributes to distinct auxin-mediated root system architecture responses.

In plants, auxin transport and development are tightly coupled, just as hormone and growth responses are intimately linked in multicellular systems. Here we provide insights into uncoupling this tight control by specifically targeting the expression of TINY ROOT HAIR 1 (TRH1), a member of plant high-affinity potassium (K+)/K+ uptake/K+ transporter (HAK/KUP/KT) transporters that facilitate K+ uptake by co-transporting protons, in Arabidopsis root cell files. Use of this system pinpointed specific root developmental responses to acropetal versus basipetal auxin transport. Loss of TRH1 function shows TRHs and defective root gravitropism, associated with auxin imbalance in the root apex. Cell file-specific expression of TRH1 in the central cylinder rescued trh1 root agravitropism, whereas positional TRH1 expression in peripheral cell layers, including epidermis and cortex, restored trh1 defects. Applying a system-level approach, the role of RAP2.11 and ROOT HAIR DEFECTIVE-LIKE 5 transcription factors (TFs) in root hair development was verified. Furthermore, ERF53 and WRKY51 TFs were overrepresented upon restoration of root gravitropism supporting involvement in gravitropic control. Auxin has a central role in shaping root system architecture by regulating multiple developmental processes. We reveal that TRH1 jointly modulates intracellular ionic gradients and cell-to-cell polar auxin transport to drive root epidermal cell differentiation and gravitropic response. Our results indicate the developmental importance of HAK/KUP/KT proton-coupled K+ transporters.

High-resolution spatiotemporal transcriptome analyses during cellularization of rice endosperm unveil the earliest gene regulation critical for aleurone and starchy endosperm cell fate specification

The major tissues of the cereal endosperm are the starchy endosperm (SE) in the inner and the aleurone layer (AL) at the outer periphery. The fates of the cells that comprise these tissues are determined according to positional information; however, our understanding of the underlying molecular mechanisms remains limited. Here, we conducted a high-resolution spatiotemporal analysis of the rice endosperm transcriptome during early cellularization. In rice, endosperm cellularization proceeds in a concentric pattern from a primary alveolus cell layer, such that developmental progression can be defined by the number of cell layers. Using laser-capture microdissection to obtain precise tissue sections, transcriptomic changes were followed through five histologically defined stages of cellularization from the syncytial to 3-cell layer (3L) stage. In addition, transcriptomes were compared between the inner and the outermost peripheral cell layers. Large differences in the transcriptomes between stages and between the inner and the peripheral cells were found. SE attributes were expressed at the alveolus-cell-layer stage but were preferentially activated in the inner cell layers that resulted from periclinal division of the alveolus cell layer. Similarly, AL attributes started to be expressed only after the 2L stage and were localized to the outermost peripheral cell layer. These results indicate that the first periclinal division of the alveolus cell layer is asymmetric at the transcriptome level, and that the cell-fate-specifying positional cues and their perception system are already operating before the first periclinal division. Several genes related to epidermal identity (i.e., type IV homeodomain-leucine zipper genes and wax biosynthetic genes) were also found to be expressed at the syncytial stage, but their expression was localized to the outermost peripheral cell layer from the 2L stage onward. We believe that our findings significantly enhance our knowledge of the mechanisms underlying cell fate specification in rice endosperm.

Imaging Calcium Dynamics in Subpopulations of Mouse Pancreatic Islet Cells.

Pancreatic islet hormones regulate blood glucose homeostasis. Changes in blood glucose induce oscillations of cytosolic calcium in pancreatic islet cells that trigger secretion of three main hormones: insulin (from β-cells), glucagon (α-cells) and somatostatin (δ-cells). β-Cells, which make up the majority of islet cells and are electrically coupled to each other, respond to the glucose stimulus as one single entity. The excitability of the minor subpopulations, α-cells and δ-cells (making up around 20% (30%) and 4% (10%) of the total rodent1 (human2) islet cell numbers, respectively) is less predictable and is therefore of special interest. Calcium sensors are delivered into the peripheral layer of cells within the isolated islet. The islet or a group of islets is then immobilized and imaged using a fluorescence microscope. The choice of the imaging mode is between higher throughput (wide-field) and better spatial resolution (confocal). Conventionally, laser scanning confocal microscopy is used for imaging tissue, as it provides the best separation of the signal between the neighboring cells. A wide-field system can be utilized too, if the contaminating signal from the dominating population of β-cells is minimized. Once calcium dynamics in response to specific stimuli have been recorded, data are expressed in numerical form as fluorescence intensity vs. time, normalized to the initial fluorescence and baseline-corrected, to remove the effects linked to bleaching of the fluorophore. Changes in the spike frequency or partial area under the curve (pAUC) are computed vs. time, to quantify the observed effects. pAUC is more sensitive and quite robust whereas spiking frequency provides more information on the mechanism of calcium increase. Minor cell subpopulations can be identified using functional responses to marker compounds, such as adrenaline and ghrelin, that induce changes in cytosolic calcium in a specific populations of islet cells.

Low Density Granulocytes in ANCA Vasculitis Are Heterogenous and Hypo-Responsive to Anti-Myeloperoxidase Antibodies.

Low Density Granulocytes (LDGs), which appear in the peripheral blood mononuclear cell layer of density-separated blood, are seen in cancer, sepsis, autoimmunity, and pregnancy. Their significance in ANCA vasculitis (AAV) is little understood. As these cells bear the autoantigens associated with this condition and have been found to undergo spontaneous NETosis in other diseases, we hypothesized that they were key drivers of vascular inflammation. We found that LDGs comprise a 3-fold higher fraction of total granulocytes in active vs. remission AAV and disease controls. They are heterogeneous, split between cells displaying mature (75%), and immature (25%) phenotypes. Surprisingly, LDGs (unlike normal density granulocytes) are hyporesponsive to anti-myeloperoxidase antibody stimulation, despite expressing myeloperoxidase on their surface. They are characterized by reduced CD16, CD88, and CD10 expression, higher LOX-1 expression and immature nuclear morphology. Reduced CD16 expression is like that observed in the LDG population in umbilical cord blood and in granulocytes of humanized mice treated with G-CSF. LDGs in AAV are thus a mixed population of mature and immature neutrophils. Their poor response to anti-MPO stimulation suggests that, rather than being a primary driver of AAV pathogenesis, LDGs display characteristics consistent with generic emergency granulopoiesis responders in the context of acute inflammation.

Optic nerve thinning and neurosensory retinal degeneration in the rTg4510 mouse model of frontotemporal dementia

Visual impairments, such as difficulties in reading and finding objects, perceiving depth and structure from motion, and impaired stereopsis, have been reported in tauopathy disorders, such as frontotemporal dementia (FTD). These impairments however have been previously attributed to cortical pathologies rather than changes in the neurosensory retina or the optic nerve. Here, we examined tau pathology in the neurosensory retina of the rTg(tauP301L)4510 mouse model of FTD. Optic nerve pathology in mice was also assessed using MRI, and corresponding measurements taken in a cohort of five FTD sufferers and five healthy controls. rTg(tauP301L)4510 mice were imaged (T2-weighted MRI) prior to being terminally anesthetized and eyes and brains removed for immunohistochemical and histological analysis. Central and peripheral retinal labelling of tau and phosphorylated tau (pTau) was quantified and retinal layer thicknesses and cell numbers assessed. MR volumetric changes of specific brain regions and the optic nerve were compared to tau accumulation and cell loss in the visual pathway. In addition, the optic nerves of a cohort of healthy controls and behavioural variant FTD patients, were segmented from T1- and T2-weighted images for volumetric study. Accumulation of tau and pTau were observed in both the central and peripheral retinal ganglion cell (RGC), inner plexiform and inner nuclear layers of the neurosensory retina of rTg(tauP301L)4510 mice. This pathology was associated with reduced nuclear density (− 24.9 ± 3.4%) of the central RGC layer, and a reduced volume (− 19.3 ± 4.6%) and elevated T2 signal (+ 27.1 ± 1.8%) in the optic nerve of the transgenic mice. Significant atrophy of the cortex (containing the visual cortex) was observed but not in other area associated with visual processing, e.g. the lateral geniculate nucleus or superior colliculus. Atrophic changes in optic nerve volume were similarly observed in FTD patients (− 36.6 ± 2.6%). The association between tau-induced changes in the neurosensory retina and reduced optic nerve volume in mice, combined with the observation of optic nerve atrophy in clinical FTD suggests that ophthalmic tau pathology may also exist in the eyes of FTD patients. If tau pathology and neurodegeneration in the retina were to reflect the degree of cortical tau burden, then cost-effective and non-invasive imaging of the neurosensory retina could provide valuable biomarkers in tauopathy. Further work should aim to validate whether these observations are fully translatable to a clinical scenario, which would recommend follow-up retinal and optic nerve examination in FTD.

Potato Tuber Greening: a Review of Predisposing Factors, Management and Future Challenges

Greening is a major cause of quality loss in potato tubers. As underground stems, potato tubers are non-photosynthetic plant organs that lack photosynthetic machinery. However, after light exposure, amyloplasts convert to chloroplasts in tuber peripheral cell layers, which cause the accumulation of the green photosynthetic pigment, chlorophyll. Tuber greening can be impacted by genetic, cultural, physiological and environmental factors including planting depth, tuber physiological age, temperature, atmospheric oxygen levels, and lighting conditions. Numerous studies have been devoted to understand and control this costly defect for the potato industry. This review brings together the available knowledge on light-induced greening, from causes to solutions and suggestions on further research with a focus on identifying the underlying mechanisms of tuber greening.

Human neutrophils can mimic myeloid-derived suppressor cells (PMN-MDSC) and suppress microbead or lectin-induced T cell proliferation through artefactual mechanisms

We report that human conventional CD15+ neutrophils can be isolated in the peripheral blood mononuclear cell (PBMC) layer during Ficoll gradient separation, and that they can impair T cell proliferation in vitro without concomitant neutrophil activation and killing. This effect was observed in a total of 92 patients with organ transplants, lung cancer or anxiety/depression, and in 18 healthy donors. Although such features are typically associated in the literature with the presence of certain myeloid-derived suppressor cell (PMN-MDSC) populations, we found that commercial centrifuge tubes that contained membranes or gels for PBMC isolation led to up to 70% PBMC contamination by CD15+ neutrophils, with subsequent suppressive effects in certain cellular assays. In particular, the suppressive activity of human MDSC should not be evaluated using lectin or microbead stimulation, whereas assays involving soluble or plate-bound antibodies or MLR are unaffected. We conclude that CD15+ neutrophil contamination, and associated effects on suppressor assays, can lead to significant artefacts in studies of human PMN-MDSC.

Papillary lesions of the breast

Papillary lesions of the breast comprise a heterogeneous group. These lesions are characterised by the presence of papillary projections of variable length and thickness composed of central fibrovascular cores covered by epithelium. The distinction among intraductal papilloma, papilloma with atypical ductal hyperplasia (ADH) or ductal carcinoma in situ (DCIS), papillary DCIS, and papillary carcinoma can be challenging. An assessment of the presence and distribution of myoepithelial cells in the lesion is one of the most helpful features in arriving at the correct diagnosis. Benign intraductal papillomas and papillomas with atypia (ADH or DCIS) have myoepithelial cells both within and surrounding the involved space. Papillary DCIS and papillary carcinomas lack myoepithelial cells within the papillary proliferation; DCIS retains a myoepithelial cell layer at the periphery and encapsulated and solid papillary carcinomas may lack a peripheral myoepithelial cell layer. Evaluation of the epithelial component is the next step. Benign papillomas have an epithelial component that is heterogeneous with variability in nuclear size, shape and cell placement. Atypia and/or carcinoma usually manifest as a monomorphic proliferation of epithelial cells with low nuclear grade atypia and areas of polarisation. Morphological features and use of adjunctive immunostains to guide diagnosis will be discussed.

Clinical application of ultra-wide field fundus autofluorescence imaging

Ultra-wide field fundus autofluorescence (FAF) imaging is a new noninvasive technique with an imaging range of about 200 °. It can detect peripheral retinal lesions that cannot be found in previous FAFs and more objectively reflect intracellular content and distribution of lipofuscin in the retinal pigment epithelium (RPE) and RPE cell metabolic status. The ultra-wide field FAF can find the abnormal autofluorescence (AF) in the peripheral retina of the eyes of age-related macular degeneration (AMD), and different AF manifestations may have an impact on the diagnosis and treatment of the different AMD subtypes. It is helpful to evaluate subretinal fluid in the eyes of central serous choroidal retinopathy and can accurately detect the changes in the outer retina of the eyes without subretinal fluid. It can help to determine the type of uveitis and fully display the evolution of the disease. It can also assess the peripheral photoreceptor cell layer and RPE in patients with retinal dystrophy and retinitis pigmentosa, and comprehensively evaluate their retinal function and monitor the progress of disease. It can also assist in the evaluation of the short-term efficacy and RPE cell function after the scleral buckling surgery for patients with rhegmatogenous retinal detachment. In the future, ultra-wide field FAF may change the knowledge and intervention strategy of ocular fundus diseases and promote the clinical and scientific research in this field. Key words: Retinal diseases/diagnosis; Choroid diseases/diagnosis; Macular degeneration/diagnosis; Diagnostic techniques, ophthalmological; Fluorescence; Review

Middle Ear Paraganglioma

A 51-year old woman underwent mastoidectomy with labyrinthectomy on the right for a polypoid external auditory canal mass accompanied by tinnitus and ear discharge. She was reported to have undergone mastoidectomy on the same site seven years prior to the present consult. The material from this prior surgery was not made available to us.
 The submitted specimen from this surgery consisted of several dark brown irregular tissue fragments with an aggregate diameter of 4.2 centimeters. Histologic sections show tumor cells arranged in “ball-like” clusters, that are surrounded by a network of sinusoidal channels. The cells are round to oval, with round, uniform nuclei that have finely granular chromatin, and moderate amounts of eosinophilic to amphophilic cytoplasm. (Figure 1) Mitoses, nuclear pleomorphism and hyperchromasia are not observed. Immunohistochemical studies show diffuse cytoplasmic positivity for synaptophysin and chromogranin. (Figure 2) The S100 stain highlights a peripheral layer of cells taking up the stain around the cell clusters. (Figure 3) Based on these features, we diagnosed the case as a paraganglioma, likely a recurrence.
 Paragangliomas are neuroendocrine neoplasms that arise from paraganglia found in various anatomic locations.1 In the middle ear, they arise from paraganglia found in the adventitia of the jugular bulb – hence, the old synonym “glomus jugulare” and “glomus tympanicum.” Other sites where they can develop include paraganglia of the carotid artery bifurcation (“chemodectoma”), the larynx, and the vagal trunk (“glomus vagale”). The World Health Organization has simplified the nomenclature of these tumors by calling all of them simply “paraganglioma” and specifying the site involved.1 In our case, it is likely a middle ear paraganglioma, borne out by the history, clinical picture, and the morphology. Head and neck paragangliomas occur in adults, from the 5th – 6th decade, more commonly in females, and present mostly with mass-related symptoms.2,3
 The morphology of paragangliomas in all head and neck locations is similar. Hematoxylin-eosin sections show cells arranged in organoid groups (“cell-ball”, “Zellballen”) surrounded by a vascular network. There are two cell types encountered: the chief cells, which comprise the bulk of the cell nests and have abundant eosinophilic cytoplasm, and the sustentacular cells, which are spindly and located at the periphery of the nests. Neuroendocrine immunohistochemical stains (e.g. synaptophysin, chromogranin, CD56) highlight the chief cells, while S100 and glial fibrillary acidic protein (GFAP) highlight the sustentacular cells. Cytokeratin is typically non-reactive and distinguishes this tumor from neuroendocrine tumors (i.e. carcinoid, neuroendocrine carcinoma), and middle ear adenoma.1,3 There are no consistent histologic features that can discriminate between benign and malignant cases, nor are there criteria that can predict aggressive behavior and metastasis.1,2,3
 Head and neck paragangliomas are slow-growing tumors, and surgery is the most common treatment option. Radiotherapy is an option, especially for vagal paragangliomas where severe vagal nerve deficits occur in surgically treated cases.1 Recurrence after surgery is reported to be less than 10% for carotid, and up to 17% in laryngeal cases.1 Metastasis on the other hand occur in 4 – 6 % of carotid, 2% of middle ear and laryngeal, and 16% of vagal tumors.3 The World Health Organization nomenclature states that “all paragangliomas have some potential for metastasis (albeit variable).”1 Thus, long-term follow-up may be prudent for all cases.

ARACINs, Brassicaceae-specific peptides exhibiting antifungal activities against necrotrophic pathogens in Arabidopsis.

Plants have developed a variety of mechanisms to cope with abiotic and biotic stresses. In a previous subcellular localization study of hydrogen peroxide-responsive proteins, two peptides with an unknown function (designated ARACIN1 and ARACIN2) have been identified. These peptides are structurally very similar but are transcriptionally differentially regulated during abiotic stresses during Botrytis cinerea infection or after benzothiadiazole and methyl jasmonate treatments. In Arabidopsis (Arabidopsis thaliana), these paralogous genes are positioned in tandem within a cluster of pathogen defense-related genes. Both ARACINs are small, cationic, and hydrophobic peptides, known characteristics for antimicrobial peptides. Their genes are expressed in peripheral cell layers prone to pathogen entry and are lineage specific to the Brassicaceae family. In vitro bioassays demonstrated that both ARACIN peptides have a direct antifungal effect against the agronomically and economically important necrotrophic fungi B. cinerea, Alternaria brassicicola, Fusarium graminearum, and Sclerotinia sclerotiorum and yeast (Saccharomyces cerevisiae). In addition, transgenic Arabidopsis plants that ectopically express ARACIN1 are protected better against infections with both B. cinerea and A. brassicicola. Therefore, we can conclude that both ARACINs act as antimicrobial peptides.

Elucidating the role of transport processes in leaf glucosinolate distribution.

In Arabidopsis (Arabidopsis thaliana), a strategy to defend its leaves against herbivores is to accumulate glucosinolates along the midrib and at the margin. Although it is generally assumed that glucosinolates are synthesized along the vasculature in an Arabidopsis leaf, thereby suggesting that the margin accumulation is established through transport, little is known about these transport processes. Here, we show through leaf apoplastic fluid analysis and glucosinolate feeding experiments that two glucosinolate transporters, GTR1 and GTR2, essential for long-distance transport of glucosinolates in Arabidopsis, also play key roles in glucosinolate allocation within a mature leaf by effectively importing apoplastically localized glucosinolates into appropriate cells. Detection of glucosinolates in root xylem sap unambiguously shows that this transport route is involved in root-to-shoot glucosinolate allocation. Detailed leaf dissections show that in the absence of GTR1 and GTR2 transport activity, glucosinolates accumulate predominantly in leaf margins and leaf tips. Furthermore, we show that glucosinolates accumulate in the leaf abaxial epidermis in a GTR-independent manner. Based on our results, we propose a model for how glucosinolates accumulate in the leaf margin and epidermis, which includes symplasmic movement through plasmodesmata, coupled with the activity of putative vacuolar glucosinolate importers in these peripheral cell layers.

Intrinsic Lens Forming Potential of Mouse Lens Epithelial versus Newt Iris Pigment Epithelial Cells in Three-Dimensional Culture

Adult newts (Notophthalmus viridescens) are capable of complete lens regeneration that is mediated through dorsal iris pigment epithelial (IPE) cells transdifferentiation. In contrast, higher vertebrates such as mice demonstrate only limited lens regeneration in the presence of an intact lens capsule with remaining lens epithelial cells. To compare the intrinsic lens regeneration potential of newt IPE versus mouse lens epithelial cells (MLE), we have established a novel culture method that uses cell aggregation before culture in growth factor-reduced Matrigel. Dorsal newt IPE aggregates demonstrated complete lens formation within 1 to 2 weeks of Matrigel culture without basic fibroblast growth factor (bFGF) supplementation, including the establishment of a peripheral cuboidal epithelial cell layer, and the appearance of central lens fibers that were positive for αA-crystallin. In contrast, the lens-forming potential of MLE cell aggregates cultured in Matrigel was incomplete and resulted in the formation of defined-size lentoids with partial optical transparency. While the peripheral cell layers of MLE aggregates were nucleated, cells in the center of aggregates demonstrated a nonapoptotic nuclear loss over a time period of 3 weeks that was representative of lens fiber formation. Matrigel culture supplementation with bFGF resulted in higher transparent bigger-size MLE aggregates that demonstrated increased appearance of βB1-crystallin expression. Our study demonstrates that bFGF is not required for induction of newt IPE aggregate-dependent lens formation in Matrigel, while the addition of bFGF seems to be beneficial for the formation of MLE aggregate-derived lens-like structures. In conclusion, the three-dimensional aggregate culture of IPE and MLE in Matrigel allows to a higher extent than older models the indepth study of the intrinsic lens-forming potential and the corresponding identification of lentogenic factors.

Dynamics of intracellular calcium in cultured human keratinocytes after localized cell damage

Recovery of cultured keratinocytes after scratch damage is considered to be a wound-healing model. In this study, we observed changes in intracellular calcium concentration ([Ca(2+) ]i ) in cultured human keratinocytes after scratch damage. Immediately after scratch damage, a wave of increased [Ca(2+) ]i radiated outward from the damaged area and then disappeared gradually. But, [Ca(2+) ]i remained elevated in a peripheral layer of cells around the damaged area for several minutes. This layer did not appear in calcium-free medium. When the culture was switched to calcium-free medium for 30min immediately after scratch damage, then switched back to standard (Ca(2+) -containing) medium, the recovery ratio after 24h was approximately 25% lower than that of the culture in standard medium throughout. We speculate that delineation of damage sites by a layer of cells with increased [Ca(2+) ]i might be part of a signalling pathway that appropriately directs the wound-healing process in epidermis.

Formation of the unusual semivolatile diterpene rhizathalene by the Arabidopsis class I terpene synthase TPS08 in the root stele is involved in defense against belowground herbivory.

Secondary metabolites are major constituents of plant defense against herbivore attack. Relatively little is known about the cell type-specific formation and antiherbivore activities of secondary compounds in roots despite the substantial impact of root herbivory on plant performance and fitness. Here, we describe the constitutive formation of semivolatile diterpenes called rhizathalenes by the class I terpene synthase (TPS) 08 in roots of Arabidopsis thaliana. The primary enzymatic product of TPS08, rhizathalene A, which is produced from the substrate all-trans geranylgeranyl diphosphate, represents a so far unidentified class of tricyclic diterpene carbon skeletons with an unusual tricyclic spiro-hydrindane structure. Protein targeting and administration of stable isotope precursors indicate that rhizathalenes are biosynthesized in root leucoplasts. TPS08 expression is largely localized to the root stele, suggesting a centric and gradual release of its diterpene products into the peripheral root cell layers. We demonstrate that roots of Arabidopsis tps08 mutant plants, grown aeroponically and in potting substrate, are more susceptible to herbivory by the opportunistic root herbivore fungus gnat (Bradysia spp) and suffer substantial removal of peripheral tissue at larval feeding sites. Our work provides evidence for the in vivo role of semivolatile diterpene metabolites as local antifeedants in belowground direct defense against root-feeding insects.

Getting to the core of platinum drug bio-distributions: the penetration of anti-cancer platinum complexes into spheroid tumour models

Elemental mapping and fluorescence imaging techniques are frequently employed to probe the distribution of platinum-based chemotherapeutics within biological systems. Although useful, these techniques have unique limitations: elemental mapping methods, such as those that use particle beams, typically require rigorous sample preparation that can alter chemical distributions, whilst in situ visible fluorescence studies require fluorescent-tagging of the platinum component and may be confounded by factors such as ligand loss. The present study aimed to establish reliable methods for accurately probing the bio-distribution of platinum compounds within the model tumour micro-environment of the well characterised DLD-1 colorectal cancer cell spheroids. 3D X-ray fluorescence computed micro-tomography (XRF-CT) was performed on intact untreated spheroids to determine the effect of physical sectioning and chemical fixation on elemental distributions. It was revealed for the first time that cisplatin can readily penetrate through DLD-1 spheroids and accumulate in the central hypoxic and necrotic regions of the spheroids. Furthermore, formalin fixing was shown to cause significant changes to the distributions and concentrations of the elements, particularly in the cases of platinum and zinc. This effect was not observed in the cryo-fixed and cryo-sectioned samples. X-ray fluorescence microscopy (XFM) was used to re-examine the fate of platinum in the previously reported fluorescence distribution studies of platinum(ii) complexes tagged with fluorescent anthraquinone moieties. In contrast to the fluorescence distributions, in which fluorescence was observed predominantly around the periphery of the spheroids, the XFM revealed a high level of platinum in the spheroid centre, indicating that ligand exchange occurred within the peripheral cell layers. Both the platinum maps and the fluorescence images exhibit similar diffusion trends, supporting the conclusion that charge on the compound can slow cellular uptake can enhance tumour penetration.

Encapsulated Papillary Carcinoma of the Breast

Papillary carcinoma (PC) of the breast, which accounts for 0.5% to 1% of breast cancer, is a distinct histologic subtype that is characterized by malignant epithelial proliferation supported by fibrovascular stalks. However, the classification of PC (whether they are in situ or invasive), its behavior, and management remain a matter of debate. In this study, we reviewed 302 PCs including 247 pure PCs without coexisting conventional non-PCs collected from 3 institutions. This included 208 (84%) intracystic PCs (IPC), 30 (12%) solid PCs (SPC), and 9 (4%) papillary ductal carcinoma in situ (DCISs). In addition, previous studies of PC were reviewed. This included 339 pure PCs of a total of 521 PC patients. Clinical and outcome analyses were carried out to assess nature and behavior of these lesions and to determine their optimal outcome-based management. SPC is more frequently associated with coexisting conventional invasive carcinoma than IPC (P<0.05). Although the majority of papillary DCIS and some cases of IPC and SPC (both called encapsulated PC) that are surrounded by an intact layer of myoepithelial cells are considered to be true in situ lesions, PC lacking a peripheral layer of myoepithelial cells can be regarded as a special type of invasive carcinoma associated with low incidence of stromal/skeletal muscle invasion, low frequency of lymph node metastasis (3%), and infrequent development of local or distant recurrence. These lesions are therefore characterized by indolent behavior and extremely favorable prognosis. Encapsulated PC can be treated with adequate local therapy. Routine use of adjuvant therapy, particularly chemotherapy, is clearly not appropriate in view of the very low risk of subsequent events. However, hormonal therapy may be indicated in certain cases such as recurrent PC.

Aural carcinoma with chondroid metaplasia at metastatic sites in a dog

A case of aural carcinoma with chondroid metaplasia at metastatic foci in an 8-year-old male pug is described. Multiple metastases in both lungs and the right submandibular, parotid, retropharyngeal, cervical and prescapular lymph nodes were detected. Histologically, the skin of the right ear canal appeared to be diffusely infiltrated by cords and nests of neoplastic epithelial cells, showing multifocal contiguity with the overlying hyperplastic squamous epithelium. Most of the carcinomatous cells were arranged in a glandular-like pattern, with formation of lumens containing epithelial cells attached to the peripheral cell layer by elongated intercellular bridges. Scattered foci of keratinization with central accumulations of compact, laminated keratin were also observed, and histochemical stains failed to detect mucinous secretory material. Even though histological and histochemical findings were compatible with a diagnosis of acantholytic squamous cell carcinoma, CAM5.2 immunostaining was detectable in the majority, although not all, neoplastic cells, confirming a diagnosis of poorly differentiated ceruminous gland carcinoma. Pulmonary metastatic nodules revealed multifocal areas of cartilaginous metaplasia with apparent transition of carcinomatous cells to chondroid cells, showing nuclear atypia and focal cytokeratin immunostaining. Carcinomatous cells surrounding chondroid areas also revealed focal vimentin and S100 immunoreactivity. Histological evidence of transition between the two components, as well as the presence of intermediate cells displaying both epithelial and mesenchymal immunohistochemical features, strongly indicated a final diagnosis of carcinosarcoma, in which chondrosarcomatous elements were derived from carcinoma cells.