Mixed Cellular Composition Research Articles

Development of a predictive model for stromal content in prostate cancer samples to improve signature performance.

Prostate cancer is heterogeneous in both cellular composition and patient outcome, and development of biomarker signatures to distinguish indolent from aggressive tumours is a high priority. Stroma plays an important role during prostate cancer progression and undergoes histological and transcriptional changes associated with disease. However, identification and validation of stromal markers is limited by a lack of datasets with defined stromal/tumour ratio. We have developed a prostate‐selective signature to estimate the stromal content in cancer samples of mixed cellular composition. We identified stromal‐specific markers from transcriptomic datasets of developmental prostate mesenchyme and prostate cancer stroma. These were experimentally validated in cell lines, datasets of known stromal content, and by immunohistochemistry in tissue samples to verify stromal‐specific expression. Linear models based upon six transcripts were able to infer the stromal content and estimate stromal composition in mixed tissues. The best model had a coefficient of determination R 2 of 0.67. Application of our stromal content estimation model in various prostate cancer datasets led to improved performance of stromal predictive signatures for disease progression and metastasis. The stromal content of prostate tumours varies considerably; consequently, deconvolution of stromal proportion may yield better results than tumour cell deconvolution. We suggest that adjusting expression data for cell composition will improve stromal signature performance and lead to better prognosis and stratification of men with prostate cancer. © 2019 The Authors. The Journal of Pathology published by John Wiley & Sons Ltd on behalf of Pathological Society of Great Britain and Ireland.

Histological heterogeneity of dysembryoplastic neuroepithelial tumour: identification and differential diagnosis in a series of 74 cases.

In a retrospective study of resected specimens from 416 patients being treated for long-standing epilepsy, 74 cases of dysembryoplastic neuroepithelial tumour (DNT) were encountered that were all characteristically composed of small round oligodendroglia-like cells (OLC), astrocytes and mature neurones in varying proportions. The architectural patterns, histological, immunohistochemical and ultrastructural features and results of cell proliferation studies and postoperative follow-up are described to facilitate the identification of DNT and to differentiate it from other intrinsic neoplasms that commonly present with seizures. The tumours presented with early onset of seizures, at a median age of 7 years, without the signs of raised intracranial pressure. A majority of the lesions were located in the temporal lobe (n = 59), with fewer cases in the frontal (n = 8), parietal (n = 6) and occipital lobes (n = 1), and ranged in size from 10 to 70 mm; 33 were cystic. Histologically three types could be distinguished, multinodular, solitary nodular and diffuse. The first type (37.8%) had the features of a typical DNT with multinodular architecture and mixed cellular composition. The second type (33.8%) consisted of a solitary nodule, while the third (28.4%) was a diffuse tumour, both composed of a similar mixture of cells as the multinodular DNT. The lesions were seen in the neocortex and white matter and tumours in the temporal lobe often involved the amygdala and hippocampus. The presence of myxoid matrix, microcystic change, calcification and leptomeningeal involvement were common. Dysplastic neurones at the periphery of the tumour and abnormalities in cortical lamination in the adjacent neocortex were found in about one-third of the resections. Rare mitotic figures were encountered in eight of the tumours and necrosis was found in two. Immunocytochemistry for glial fibrillary acidic protein (GFAP) and neuronal markers neuron-specific enolase, synaptophysin and neurofilament (RT 97) assists in establishing the diagnosis, highlighting the astrocytic and neuronal components, and the OLC, by the absence of expression of GFAP. Electron microscopy showed that in some cases OLC show neuronal differentiation. Although the proliferating cell nuclear antigen labelling index varied between 0 and 45.5%, 20 of the 51 tumours stained failed to express the antigen, in keeping with the indolent nature of this neoplasm. The response to surgery was excellent; none of the tumours have recurred, and the control of seizures remained good. Despite some histological heterogeneity, the clinical and pathological features and indolent biological behaviour indicate that these tumours constitute a single distinct entity. The spectrum of morphological appearances of DNT is broader than has been previously reported, the recognition of which is needed to avoid unnecessary neoadjuvant therapy.

Characterization of Titanium Alloy Particulates to Study the in Vitro Release of Inflammatory Mediators by Human Peripheral Blood Monocytes.

Abstract Particulate wear debris found around joint arthroplasties has been linked to the premature failure of artificial joints. Cytokines and eicosanoids released by macrophages are known mediators of inflammation and osteolysis. Previous in vitro studies of wear debris-mediated inflammation have relied upon poorly characterized particulates and peripheral blood cell fractions of mixed cellular composition. The objective of this study was to utilize titanium particulates that closely match wear debris found around joint arthroplasties and to study their effects on the biosynthesis of inflammatory mediators by isolated monocytes. To mimic wear debris that surrounds artificial joints, titanium alloy particulates (1-3 μm in diameter) were obtained. A submicron fraction of these particulates was isolated by differential sedimentation. The morphology, size and concentration of the resulting population was characterized utilizing scanning electron microscopy. Titanium particulate size was estimated from photomicrographs of calibrated latex microspheres mixed with titanium particles (Figure 1). A known volume of titanium particulates in suspension was applied to a carbon planchette and allowed to dry.

Signaling events during male germ cell differentiation: bases and perspectives.

In all species, reproductive function depends on the ability of the individual to produce functional differentiated gametes. Spermatogenesis is a cyclic process in which diploid spermatogonia differentiate into mature haploid spermatozoa. Thus from a genetic point of view, spermatogenesis can be divided into two phases, namely the diploid and haploid phase. Indeed, this complex differentiation process is still more intriguing since primary spermatocytes, if genetically diploid, are functionally tetraploid, while elongating spermatids, the germ cells undergoing the most dramatic morphological changes, if genetically haploid, become functionally anucleate due to ongoing condensation of chromatin resulting in an inactive nuclear DNA. This multi-step differentiative pathway is dependent on a specific environment provided by the anatomical and cellular relationships that take place in the testis and more specifically within the seminiferous tubules. Already, early anatomists (mind comes to Enrico Sertoli and Gustaf Retzius) were fascinated by the mixed cellular composition of the testis correctly deciphered as a whole of interacting and interdependent cell types despite the fact these belong to two well-established and different cell lineages, i.e, the somatic and germinal line. Since their time (the XIX century) up to-day a conspicuous bulk of experimental work and a relative massive bibliographic documentation have been provided. From this it stands out : a) a sophisticated role played by the cyclic hormonal control elicited by the hypothalamic-pituitary axis; b) the structural membrane specializations of Sertoli-germ cell communications; c) the existence and action of a paracrine and autocrine testicular regulative secretion; d) a regulation of germ cell gene expression, highly specialized both at transcriptional, posttranscriptional, and translational level; e) an active participation of the haploid genome in the final steps of cell differentiation. Each of these points has been the matter of several more and less recent reviews to which the present author hands back in the course of this note. However all these points, although topics of separate and extensive treatises, are conceptually jointed by a 'leit-motiv', that is, the intracellular transduction of an exogenous signal evoking a specific stimulatory/inhibitory, proliferative/differentiative event. The spirit with which the present author interpreted this minireview was to recall some points to which to draw attention having as a scenario the complex process of male germ cell differentiation in mammals.

Inflammatory Pseudotumor of the Lung in Children

Two children with inflammatory pseudotumor (IPT) of the lung are reported. Symptomless "cystic" lesions were present on routine chest x ray. Morphological study of these peculiar lesions included light microscopic, immunohistochemical, and ultrastructural analysis. Histologic appearance of the lesion varied from the features of granulation tissue on the periphery to bundles of spindle-shaped cells in the central area. Immunohistochemical findings had no diagnostic value but were helpful in excluding other tumors. Ultrastructural analysis confirmed the mixed cellular composition and benign nature of the lesion. Etiopathogenesis of this process is unknown. IPT can be differentiated from similar lesions and must not be mistaken for malignant tumor. Proper treatment by complete surgical removal of the lesion usually cures the patient.

STUDIES ON THE MORPHOGENESIS OF THE TUMORS EXPERIMENTALLY INDUCED BY ETHYLNITROSOUREA WITH SPECIAL REFERENCE TO THE LIGHT AND ELECTRON MICROSCOPY OF MICROTUMORS

Tumors of the nervous system were induced in rats of Donryu strain by a single injection of 50mg/kg.b.w. of ethylnitrosourea (ENU) through the mothers. A total of 126 tumors were produced in 92 of 117 treated offsprings. The survival time of animals with tumor development ranged from 53 to 607 days. The neural tumors amounted 104, comprising 82.5% of the total number of neoplasms. Besides grossly visible tumors, histological examination of the brain and spinal cord disclosed a total of 166 foci of glial cell hyperplasia or tumors of microscopic size. On histological sections 86 of these lesions measured less than lmm in diameter, 61 between 1 and 2mm, and 19 more than 2mm. The predominant cell type of the smaller lesions was either astrocytic or oligodendroglial. With increasing tumor size, a number of microtumors with a mixed cellular composition became frequent. Sites of predilection for such microtumors were the subcortical white matter of the brain, the hippocampus, the paraventricular areas, the basal ganglia, and the spinal cord. It would seem that grossly visible tumors are formed by expansion and fusion of these lesions of microscopic size and by development of anaplasia of constituent glial cells.Light and electron microscopic studies were also made on the brain and the trigeminal nerve of rats treated transplacentally with ENU at intervals of 10, 35, 80, 120, 150, 200, 250, 300 and 400 days after birth. A total of 48 microtumors were found in the brain of rats which had survived over 120 days. Electron microscopy disclosed these lesions to be largely composed of cells with ultrastructural features of astrocyte and oligodendroglia. The presence of a large amount of extracellular matrix was considered in part to account for the honeycombed structure typical of oligodendroglial microtumors in light microscopy. Observations of the trigeminal nerve disclosed occasional foci of diffuse endoneurial cell proliferation which started to arise from the 80th day. At the ultrastructural level, the proliferating cells were found to retain a typical Schwann cell appearance and relationship to axon. The nerve fiber was often surrounded by numerous cell processes, forming onion bulb-like structure.The third experiment was undertaken to investigate the acute cytotoxic effect of ENU on the nervous system. A single dose of 50 or 100mg ENU was given to rats perinatally and the nervous system was examined with light and electron microscopy at intervals from 6 to 48 hours after injection. A considerable proportion of cells constituting subependymal matrix layer of the lateral ventricle and extragranular layer of the cerebellum were found undergoing degeneration with disappearance of mitotic figures after 6 to 12 hours. Schwann cells in the trigeminal nerve and glial cells of the cerebral white matter were also found similarly involved. Neurons seemed to be less affected.From these observations it was concluded that oligodendroglia, astrocytes and Schwann cells are the most susceptible targets in the brain and nerve to carcinogenic nitrosourea compounds.

HISTOPATHOLOGICAL STUDIES OF NERVOUS SYSTEM TUMORS IN RATS INDUCED BY TRANSPLACENTAL ADMINISTRATION OF ETHYLNITROSOUREA

Sixteen pregnant rats of Donryu Strain were given intravenously with a single dose of 50 mg/ kg of Ethylnitrosourea (ENU) on the 15th day (Group I, 9 rats) and the 20th day (Group II, 7 rats) of gestation.A total of 126 tumors (Group I, 61 and Group II, 65) were produced in 92 of 117 treated offspring which had survived into tumor bearing age. The mean survival time of Group I rats with tumor developement was 317 days after brith and that of Group II rats was 276.The sites of the total of 126 tumors were formed as following : 27 were produced in the brain (Group I, 21 and Group II, 6), 21 in the spinal cord, 42 in the cranial nerve and ganglia, 8 in the spinal nerve roots, 6 in the peripheral nerves and 22 in the extraneural organs. The neural tumors amouted 104, comprising 82.5% of the total number of the neoplasm.Significant differences in incidence of the tumors of the brain and those in extraneural organs were demonstrated between Group I and Group II rats.According to the cytology and the pattern of predominant tumor cells, tumors of the brain and spinal cord were classified into the following types : mixed glioma (18), oligodendroglioma (18), anaplastic astrocytoma or anaplastic glioma (6), ependymoma-like tumor (5) and unclassified tumor (1). The histology of mixed glioma and oligodendroglioma were most common. 5 tumors produced in the spinal cord were classified as ependymoma-like tumor and they showed an isomorphic cell appearance with such architectural characteristics as crowns of cell nuclei around vascular vessels and pseudorosettes. No tumors were found with typical ependymal rosettes.Almost all the cranial nerve tumors were located in the trigeminal nerve and Gasserian ganglia, microscopically the majority of neurinomas were highly anaplastic with friquent mitotic figures.Besides grossly visible tumors, histological examinations of the brain and the spinal cord disclosed a total of 138 (Group I, 84 and Group II, 54) foci of glial cell hyperplasia or tumors of microscopic size. Sites of predilection for such foci or small microtumors were the subcortical white matter of the brain, the basal ganglia, the spinal cord, the hippocumpus and the periventricular areas. The predominant cell type of such lesions was either oligodendroglial or astrocytic glia. With increasing tumor size, a number of microtumors with a mixed cellular composition became frequent. There are no focus of the ependymal cell hyperplasia.The transplantation experiment demonstrated that anaplastic neurinomas were highly transplantable and capable of subsequent transfers through a number of generations.This experiment demonstrated that a single transplacental exposure of ENU was capable of inducing neuroectodermal tumors, and probably taget cells of it were the astroglia, the oligodendroglia and Schwann's sheath cells.

HISTOPATHOLOGIC and ELECTRON MICROSCOPE STUDIES of THE EXPERIMENTAL MOUSE GLIOMAS and THEIR TRANSPLANTS

Experimental induction of gliogenous tumors was made in a total of 135 mice of C3H and C57Black strain by intra-cerebral and -cerebellar inoculation of pellets of methylcholanthrene. Fourty-nine animals were found with tumor development in a period of 135 to 528 days.By histological examinations, the tumors were found to consist of 21 gliomas, 8 mixed glioma and and sarcomas, 18 sarcomas, and 2 unclassified tumors. Histological appearance of experimental gliomas was, in general, characterized by cytological malignancy and their mixed cellular composition. Based upon the grade of anaplasia, and the shape and growth pattern pf the predominant tumor cells, a subclassification was made. They were composed of 10 glioblastomas, 3 oligodendroglioma-like, 3 astrocytoma-like and 2 ependymoma-like tumors. The majority of gliomas, however, includes mixed or transitional features between one histological type and another.Nineteen tumors had developed in the cerebellum. There was no tumor incidence with the histology and the ultrastructure suggestive of those of medulloblastoma in man.Because of the histological malignancy and the frequency of mixed gliomas, no significant data was obtained as to the topographical peculiarities in different histological types of experimental gliomas.Twenty-eight tumors including 14 gliomas, were successfully transplanted. They were capable of subsequent transfer into the subcutis and the brain of the mice of the same strain through a number of generations. By repeated transfer, the transplant came to contain uniform cells with more undifferentiated appearance. In addition, the tumors with mixed cellular composition came to separate into their original component parts.From those observations, it is confirmed that experimental mouse gliomas have peculiarities in their cytological and biological malignancy, mixed cellular composition and their frequency of concomitant neoplastic proliferation of mesenchymal tissue elements.