Tissue Growth Patterns Research Articles

Small AAAs: Recommendations for Rodent Model Research for the Identification of Novel Therapeutics.

Most abdominal aortic aneurysms (AAAs) are small with low rupture risk (<1%/y) when diagnosed but slowly expand to ≥55 mm and undergo surgical repair. Patients and clinicians require medications to limit AAA growth and rupture, but drugs effective in animal models have not translated to patients. Use models that simulate human AAA tissue pathology, growth patterns, and rupture; focus on the clinically relevant outcomes of growth and rupture; design studies with the rigor required of human clinical trials; monitor AAA growth using reproducible ultrasound; and perform studies in both males and females. The aortic adventitial elastase oral β-aminopropionitrile model has many strengths including simulating human AAA pathology and modeling prolonged aneurysm growth. The Ang II (angiotensin II) model performed less well as it better simulates acute aortic syndrome than AAA. The elastase plus TGFβ (transforming growth factor-β) blocking antibody model displays a high rupture rate, making prolonged monitoring of AAA growth not feasible. The elastase perfusion and calcium chloride models both display limited AAA growth.

Topological analysis of 3D digital ovules identifies cellular patterns associated with ovule shape diversity.

Tissue morphogenesis remains poorly understood. In plants, a central problem is how the 3D cellular architecture of a developing organ contributes to its final shape. We address this question through a comparative analysis of ovule morphogenesis, taking advantage of the diversity in ovule shape across angiosperms. Here, we provide a 3D digital atlas of Cardamine hirsuta ovule development at single cell resolution and compare it with an equivalent atlas of Arabidopsis thaliana. We introduce nerve-based topological analysis as a tool for unbiased detection of differences in cellular architectures and corroborate identified topological differences between two homologous tissues by comparative morphometrics and visual inspection. We find that differences in topology, cell volume variation and tissue growth patterns in the sheet-like integuments and the bulbous chalaza are associated with differences in ovule curvature. In contrast, the radialized conical ovule primordia and nucelli exhibit similar shapes, despite differences in internal cellular topology and tissue growth patterns. Our results support the notion that the structural organization of a tissue is associated with its susceptibility to shape changes during evolutionary shifts in 3D cellular architecture.

Mechanical control of cell proliferation patterns in growing epithelial monolayers

Cell proliferation plays a crucial role in regulating tissue homeostasis and development. However, our understanding of how cell proliferation is controlled in densely packed tissues is limited. Here we develop a computational framework to predict the patterns of cell proliferation in growing epithelial tissues, connecting single-cell behaviors and cell-cell interactions to tissue-level growth. Our model incorporates probabilistic rules governing cell growth, division, and elimination, also taking into account their feedback with tissue mechanics. In particular, cell growth is suppressed and apoptosis is enhanced in regions of high cell density. With these rules and model parameters calibrated using experimental data for epithelial monolayers, we predict how tissue confinement influences cell size and proliferation dynamics and how single-cell physical properties influence the spatiotemporal patterns of tissue growth. In this model, mechanical feedback between tissue confinement and cell growth leads to enhanced cell proliferation at tissue boundaries, whereas cell growth in the bulk is arrested, recapitulating experimental observations in epithelial tissues. By tuning cellular elasticity and contact inhibition of proliferation we can regulate the emergent patterns of cell proliferation, ranging from uniform growth at low contact inhibition to localized growth at higher contact inhibition. We show that the cell size threshold at G1/S transition governs the homeostatic cell density and tissue turnover rate, whereas the mechanical state of the tissue governs the dynamics of tissue growth. In particular, we find that the cellular parameters affecting tissue pressure play a significant role in determining the overall growth rate. Our computational study thus underscores the impact of cell mechanical properties on the spatiotemporal patterns of cell proliferation in growing epithelial tissues.

Protein Synthesis Is Stimulated in Nutritionally Obese Rats

To investigate the tissue growth and the protein synthesis in vivo in nutritional obesity we used lipid-rich multichoice diet feeding. Young male rats of the Wistar strain were divided in two groups: control and obese. Control rats were fed pelleted nonpurified diet. Obese rats were fed a multichoice diet based on a variety of highly palatable energy-rich human foods for 30 d. Protein intake was kept equal in the groups to avoid its influence on protein turnover. The tissue growth pattern was evaluated by protein, DNA and RNA contents of liver, kidney, heart, skeletal muscles and small intestine. Protein synthesis in vivo was measured in these tissues by the phenylalanine flooding-dose technique. Rats fed the multichoice diet showed significantly greater body growth when compared with rats fed the nonpurified diet. Adipose and other tissue weights were significantly greater in the obese rats. The tissue growth pattern was characterized mainly by hyperplasia. In most tissues the net protein accretion found in obese rats resulted from an enhancement in the fractional rate of protein synthesis. The greater protein synthesis was due to an increase in the efficiency of ribosomes in kidney, heart and skeletal muscle and to an increase in the synthetic capacity in liver and small intestine. These data suggest that excess energy intake when protein intake is adequate stimulates tissue growth and protein synthesis in rats.

Disturbances of the stomatognathic system and possibilities of its correction in patients with craniofacial morphea.

Morphea en coup de sabre and progressive hemifacial atrophy are extremely rare connective tissue disorders causing facial deformity. In extreme cases, morphological disorders are accompanied by symptoms of a clear impairment of the stomatognathic system. The aetiology of the above-mentioned diseases is still unknown. Properly planned therapy in the field of maxillofacial orthopaedics makes it possible to correct the asymmetric pattern of hard tissue growth and thus enable rehabilitation. The task of augmentation techniques is the volumetric supplementation of tissue defects resulting from atrophic processes. The degree of destruction and the extent of changes determine the method of correction. Mild and moderate defects are treated mainly with biomaterials and autologous adipose tissue. The severe course of hemifacial atrophy and morphea en coup de sabre and the associated significant tissue atrophy necessitate the search for more complex methods of treatment. In this paper, we summarize the disturbances of the stomatognathic system in patients with craniofacial morphea, together with an analysis of current treatment options.

Differentiating Enchondromas and Atypical Cartilaginous Tumors in Long Bones with Computed Tomography and Magnetic Resonance Imaging.

The differentiation between the atypical cartilaginous tumor (ACT) and the enchondromas is crucial as ACTs require a curettage and clinical as well as imaging follow-ups, whereas in the majority of cases enchondromas require neither a treatment nor follow-ups. Differentiating enchondromas from ACTs radiologically remains challenging. Therefore, this study evaluated imaging criteria in a combination of computed tomography (CT) and magnetic resonance (MR) imaging for the differentiation between enchondromas and ACTs in long bones. A total of 82 patients who presented consecutively at our institution with either an ACT (23, age 52.7 ±18.8 years; 14 women) or an enchondroma (59, age 46.0 ± 11.1 years; 37 women) over a period of 10 years, who had undergone preoperative MR and CT imaging and subsequent biopsy or/and surgical removal, were included in this study. A histopathological diagnosis was available in all cases. Two experienced radiologists evaluated several imaging criteria on CT and MR images. Likelihood of an ACT was significantly increased if either edema within the bone (p = 0.049), within the adjacent soft tissue (p = 0.006) or continuous growth pattern (p = 0.077) were present or if the fat entrapment (p = 0.027) was absent on MR images. Analyzing imaging features on CT, the likelihood of the diagnosis of an ACT was significantly increased if endosteal scalloping >2/3 (p < 0.001), cortical penetration (p < 0.001) and expansion of bone (p = 0.002) were present and if matrix calcifications were observed in less than 1/3 of the tumor (p = 0.013). All other imaging criteria evaluated showed no significant influence on likelihood of ACT or enchondroma (p > 0.05). In conclusion, both CT and MR imaging show suggestive signs which can help to adequately differentiate enchondromas from ACTs in long bones and therefore can improve diagnostics and consequently patient management. Nevertheless, these features are rare and a combination of CT and MR imaging features did not improve the diagnostic performance substantially.

Role of Distraction Osteogenesis in the Management of Postankylotic Deformity.

Distraction osteogenesis (DO) has evolved in maxillofacial surgery and gained popularity due to the limitations of orthognathic surgery in gross asymmetry cases. The primary aim of the paper was to determine if the use of DO for the management of severe deformities of the mandible secondary to temporomandibular joint ankylosis can achieve optimal results, with or without genioplasty, based on cephalometric norms. The secondary aim of this study was to evaluate the complications associated with DO in this group of patients. Six patients with postankylotic deformity were included. Both internal and external devices were used for an average mandibular corpus lengthening of 15mm with adjunctive procedure genioplasty. All patients had excellent outcome in terms of profile, functional occlusion, and mouth opening without deviation. Two patients had primary genioplasty showed excellent compliance and 2 as secondary at the time of device removal. Complications noted were, difficulty in vector control during distraction, paresthesia, occlusal discrepancy, scarring, and relapse of 2 to 3mm. Preorthodontics and postorthodontics were done in all patients to settle the occlusion, which was stable after 2-year follow-up. Case series shows such gross deformities pose a greater challenge due to undergrowth, gross midline shift, and discrepancy between soft and hard tissue growth pattern and the desired results can be achieved by precise planning. Genioplasty at the time of device placement has definitive positive effect on patient compliance. Though orthognathic surgery has a definitive role in minor deformity, whereas in gross deformities DO with precise planning using 3-dimensional model and vector controlled technique offers excellent outcome.

ECM degradation in the Drosophila abdominal epidermis initiates tissue growth that ceases with rapid cell-cycle exit

SummaryDuring development, multicellular organisms undergo stereotypical patterns of tissue growth in space and time. How developmental growth is orchestrated remains unclear, largely due to the difficulty of observing and quantitating this process in a living organism. Drosophila histoblast nests are small clusters of progenitor epithelial cells that undergo extensive growth to give rise to the adult abdominal epidermis and are amenable to live imaging. Our quantitative analysis of histoblast proliferation and tissue mechanics reveals that tissue growth is driven by cell divisions initiated through basal extracellular matrix degradation by matrix metalloproteases secreted by the neighboring larval epidermal cells. Laser ablations and computational simulations show that tissue mechanical tension does not decrease as the histoblasts fill the abdominal epidermal surface. During tissue growth, the histoblasts display oscillatory cell division rates until growth termination occurs through the rapid emergence of G0/G1 arrested cells, rather than a gradual increase in cell-cycle time as observed in other systems such as the Drosophila wing and mouse postnatal epidermis. Different developing tissues can therefore achieve their final size using distinct growth termination strategies. Thus, adult abdominal epidermal development is characterized by changes in the tissue microenvironment and a rapid exit from the cell cycle.

Extracellular Matrix Optimization for Enhanced Physiological Relevance in Hepatic Tissue-Chips.

The cellular microenvironment is influenced explicitly by the extracellular matrix (ECM), the main tissue support biomaterial, as a decisive factor for tissue growth patterns. The recent emergence of hepatic microphysiological systems (MPS) provide the basic physiological emulation of the human liver for drug screening. However, engineering microfluidic devices with standardized surface coatings of ECM may improve MPS-based organ-specific emulation for improved drug screening. The influence of surface coatings of different ECM types on tissue development needs to be optimized. Additionally, an intensity-based image processing tool and transepithelial electrical resistance (TEER) sensor may assist in the analysis of tissue formation capacity under the influence of different ECM types. The current study highlights the role of ECM coatings for improved tissue formation, implying the additional role of image processing and TEER sensors. We studied hepatic tissue formation under the influence of multiple concentrations of Matrigel, collagen, fibronectin, and poly-L-lysine. Based on experimental data, a mathematical model was developed, and ECM concentrations were validated for better tissue development. TEER sensor and image processing data were used to evaluate the development of a hepatic MPS for human liver physiology modeling. Image analysis data for tissue formation was further strengthened by metabolic quantification of albumin, urea, and cytochrome P450. Standardized ECM type for MPS may improve clinical relevance for modeling hepatic tissue microenvironment, and image processing possibly enhance the tissue analysis of the MPS.

ECM Remodeling and an Abrupt, Stochastic Transition to Arrest Determine Tissue Growth Kinetics

During development, multicellular organisms undergo stereotypical patterns of tissue growth in space and time, but how this is orchestrated remains unclear. Drosophila histoblast nests are small clusters of progenitor epithelial cells that undergo extensive growth to give rise to the abdominal epidermis and are amenable to live-imaging. Our quantitative analysis of the temporal dynamics of abdomen growth reveals that histoblasts display oscillatory cell division rates and that growth termination occurs through the rapid emergence of arrested cells rather than a gradual increase in cell cycle time. By examining tissue mechanics throughout histoblast expansion, we uncover an increase in tissue stress together with a decrease in extracellular matrix resistance as the histoblasts expand. The decrease in resistance is driven by timely extracellular matrix remodeling, which is necessary to trigger tissue expansion. Thus, changes in the tissue microenvironment, and a rapid cell cycle exit, control the formation of the adult Drosophila abdomen.

Control of osteoblast regeneration by a train of Erk activity waves.

SummaryRegeneration is a complex chain of events that restores a tissue to its original size and shape. The tissue-wide coordination of cellular dynamics needed for proper morphogenesis is challenged by the large dimensions of regenerating body parts. Feedback mechanisms in biochemical pathways can provide effective communication across great distances1-5, but how they might regulate growth during tissue regeneration is unresolved6,7. Here, we report that rhythmic traveling waves of Erk activity control the growth of bone in time and space in regenerating zebrafish scales, millimetre-sized discs of protective body armour. We find that Erk activity waves travel as expanding concentric rings, broadcast from a central source, inducing ring-like patterns of osteoblast tissue growth. Using a combination of theoretical and experimental analyses, we show that Erk activity propagates as excitable trigger waves able to traverse the entire scale in approximately two days, with the frequency of wave generation controlling the rate of scale regeneration. Furthermore, periodic induction of synchronous, tissue-wide Erk activation in place of travelling waves impairs tissue growth, indicating that wave-distributed Erk activation is key to regeneration. Our findings reveal trigger waves as a regulatory strategy to coordinate cell behaviour and instruct tissue form during regeneration.

From genes to shape during metamorphosis: a history.

Metamorphosis (Greek for a state of transcending-form or change-in-shape) refers to a dramatic transformation of an animal's body structure that occurs after development of the embryo or larva in many species. The development of a fly (or butterfly) from a crawling larva (or caterpillar) that forms a pupa (or chrysalis) before eclosing as a flying adult is a classic example of metamorphosis that captures the imagination and has been immortalized in children's books. Powerful genetic experiments in the fruit fly Drosophila melanogaster have revealed how genes can instruct the behaviour of individual cells to control patterns of tissue growth, mechanical force, cell-cell adhesion and cell-matrix adhesion drive morphogenetic change in epithelial tissues. Together, the distribution of mass, force and resistance determines cell shape changes, cell-cell rearrangements, and/or the orientation of cell divisions to generate the final form of the tissue. In organising tissue shape, genes harness the power of self-organisation to determine the collective behaviour of molecules and cells, which can often be reproduced in computer simulations of cell polarity and/or tissue mechanics. This review highlights fundamental discoveries in epithelial morphogenesis made by pioneers who were fascinated by metamorphosis, including D'Arcy Thompson, Conrad Waddington, Dianne Fristrom and Antonio Garcia-Bellido.

Modified Two-Stage Split Technique for Controlled Ridge Augmentation in Horizontally Atrophic Posterior Mandible: the First Stage of Research.

Various bone grafting methods are applied to eliminate horizontal atrophy of the jaws. However, problem complexity brings about ongoing research and development of new ways to achieve the predicted stable and long-term results of implantological treatment.The aim of the study was to evaluate the results of the developed method for bone grafting, a modified two-stage split technique for controlled ridge augmentation in horizontally atrophic posterior mandible, using radiological analysis data.Materials and Methods.The study group included 18 patients with horizontally atrophic posterior mandible. According to cone beam computed tomography, 39 jaw segments were assessed before plastic surgery and after applying the two-stage split-crest technique for controlled ridge augmentation. The alveolar ridge width was estimated in the area of its top and at a distance of 1, 3, 5 mm from it using the vector of future implant position and taking into account the angle of inclination of the atrophic region of the mandible.Results.When analyzing edentulous areas in the posterior mandible before treatment, there was rather a large angle of lingual inclination of the alveolar ridge. After 6 months, the average increase in bone tissue width in the region of the alveolar ridge top was 82%, it was 50.6% at a height of 1 mm from the top of the crest, 58.8% at 3 mm height, 46.7% at 5 mm (p≤0.05). Certain patterns of bone tissue growth were revealed depending on the structure of the reconstructed area. The most significant results were obtained in the molar segments of the mandible.Conclusion.The developed modified two-stage split technique for alveolar ridge augmentation allows achieving the required volume of bone tissue in the posterior mandible for successful implant treatment.

Continuous Dynamic Modeling of Regulated Cell Adhesion: Sorting, Intercalation, and Involution

Cell-cell adhesion is essential for tissue growth and multicellular pattern formation and crucial for the cellular dynamics during embryogenesis and cancer progression. Understanding the dynamical gene regulation of cell adhesion molecules (CAMs) responsible for the emerging spatial tissue behaviors is a current challenge because of the complexity of these nonlinear interactions and feedback loops at different levels of abstraction—from genetic regulation to whole-organism shape formation. To extend our understanding of cell and tissue behaviors due to the regulation of adhesion molecules, here we present a novel, to our knowledge, model for the spatial dynamics of cellular patterning, growth, and shape formation due to the differential expression of CAMs and their regulation. Capturing the dynamic interplay between genetic regulation, CAM expression, and differential cell adhesion, the proposed continuous model can explain the complex and emergent spatial behaviors of cell populations that change their adhesion properties dynamically because of inter- and intracellular genetic regulation. This approach can demonstrate the mechanisms responsible for classical cell-sorting behaviors, cell intercalation in proliferating populations, and the involution of germ layer cells induced by a diffusing morphogen during gastrulation. The model makes predictions on the physical parameters controlling the amplitude and wavelength of a cellular intercalation interface, as well as the crucial role of N-cadherin regulation for the involution and migration of cells beyond the gradient of the morphogen Nodal during zebrafish gastrulation. Integrating the emergent spatial tissue behaviors with the regulation of genes responsible for essential cellular properties such as adhesion will pave the way toward understanding the genetic regulation of large-scale complex patterns and shapes formation in developmental, regenerative, and cancer biology.

Abstract 46: 3D reconstruction and quantitative analysis of histology for prostate cancer

Abstract The integration of serial sectioning of tissue, digital whole slide imaging (WSI) and computational reconstruction algorithms enable the examination of histological samples in 3D at subcellular resolution. This allows visualizing and analyzing the imaged sample in its true three-dimensional context, offering a more comprehensive view on its spatial and morphological characteristics than that obtained via typical 2D examination. The advantages of reconstructing 3D models computationally using WSI over direct 3D imaging include the combination of high resolution, large sample sizes and compatibility with existing biochemical techniques such as in situ hybridization, immunohistochemistry and established histological staining and interpretation protocols. For this purpose, we developed a software pipeline to perform routine 3D reconstruction tasks for large image sizes and datasets in a fully automatic manner. The steps in our 3D reconstruction process are image acquisition, alignment of images to a shared coordinate space, and visualization of the reconstructed 3D data. We optimized algorithm selection and computationally intensive hyperparameter tuning using a quantitative benchmarking framework and Bayesian optimization. Further, we applied our existing pipeline for feature based analysis of tissue and extended it into 3D, allowing quantification and visualization of hundreds of features characterizing the tissue. We currently apply this system to characterize prostate cancer tumors. Prostate cancer is a heterogenous, often multifocal disease. In order to understand why and how certain tumor foci develop to a life-threatening disease over others, the tissue growth patterns and evolution of tumors with different genetic backgrounds need to be studied. We use mouse models of prostate cancer to study early tumor development connected to common genetic cancer alterations. By computing hundreds of features from the histology, and studying these in the spatial context, we gain important information of tumor characteristics as well as intra- and intertumor heterogeneity. In the future, we will further scale up the protocol to perform 3D reconstruction for serially sectioned human prostates in the near future. Citation Format: Pekka Ruusuvuori, Kimmo Kartasalo, Mira Valkonen, Masi Valkonen, Tapio Visakorpi, Matti Nykter, Leena Latonen. 3D reconstruction and quantitative analysis of histology for prostate cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 46.

The original boneheads: histologic analysis of the pachyostotic skull roof in Permian burnetiamorphs (Therapsida: Biarmosuchia).

Thickened, pachyostotic skulls are best known in pachycephalosaur dinosaurs, but evolved convergently in Permian burnetiamorphs as well as in some other stem-mammal groups and Triassic archosauromorphs. Until now, only pachycephalosaur domes have been histologically sampled to reveal patterns of bone tissue microstructure and growth. Using computed tomography and osteohistology, we serially thin-sectioned one of the smallest burnetiamorph skull caps ever recovered (estimated skull length=10cm), as well as an individual nearly twice as large, and here report the first cranial histological data from this clade. We recognize four highly vascularized histological zones visible in coronal thin-sections, only one of which shares morphological similarities with the tripartite zonation previously reported in pachycephalosaur domes. Zone A forms the endocranial region of the skull cap and records disorganized primary osteons in a fibrolamellar complex. Zone B preserves a border of compact, avascular layers of parallel-fibered bone surrounding an interior of partially remodeled vascular canals. Interestingly, the outline of Zone B resembles the shape of an incipient skull roof. Zone C forms the thickest portion of the skull cap and is composed of fast-growing woven bone with minimal osteonal development. The superficial Zone D has a matrix of predominantly woven bone with narrower primary vascular canals than in deeper regions of the skull caps. Unlike in pachycephalosaurs, where primary vascular porosity is thought to decrease through ontogeny, both burnetiamorph skull caps preserve a thick Zone C of highly vascularized tissue. Additionally, the remnants of sutures are visible as radial struts that taper superficially, leaving no trace on the surface of the skull. Even in the smallest individual, the sutures are closed ectocranially, which is unusual, given that some large, presumably adult pachycephalosaur domes preserve open sutural gaps. Although pachycephalosaur and burnetiamorph skull domes are superficially similar, histological analysis reveals differences in their vascularity and construction that imply multiple evolutionary pathways to form an elaborate pachyostotic dome.

Palaeohistology and life history evolution in cave bears, Ursus spelaeus sensu lato.

The abundance of skeletal remains of cave bears in Pleistocene deposits can offer crucial information on the biology and life history of this megafaunal element. The histological study of 62 femora from 23 different European localities and comparisons with specimens of five extant ursid species revealed novel data on tissue types and growth patterns. Cave bear’s femoral bone microstructure is characterized by a fibrolamellar complex with increasing amounts of parallel-fibered and lamellar bone towards the outer cortex. Remodelling of the primary bone tissue initially occurs close to the perimedullary margin of the bone cortex around the linea aspera. Although similar histological traits can be observed in many extant bear species, the composition of the fibrolamellar complex can vary greatly. Cave bears reached skeletal maturity between the ages of 10 and 14, which is late compared to other bear species. There is a significant correlation between altitude and growth, which reflects the different body sizes of cave bears from different altitudes.

Facial soft tissue growth in identical twins.

The aims of this longitudinal analysis of untreated monozygotic twins were to investigate the change of the facial soft tissues during growth, to determine the concordance of soft tissue growth patterns between genetically identical twins, and to assess the genetic component of soft tissue development. The sample consisted of 33 pairs of untreated monozygotic twins (23 male, 10 female) from the Forsyth Moorrees Twin Study (1959-1975); lateral cephalograms taken from 6 to 18years of age were analyzed at 3-year intervals. Cephalograms were traced, and longitudinal changes in the soft tissue profile between twins were analyzed with intraclass correlation coefficients and linear regression modelling. The concordance between monozygotic twins at 18years of age was moderate to high with intraclass correlation coefficients values between 0.37 and 0.87. Additionally, female twins showed higher concordance at 18years of age than did male twins for all included variables. However, about 10% to 46% of the twin pairs had large differences in their soft tissue parameters, even after the growth period. Although monozygotic twins possess the same genetic material, differences in the soft tissues were found. This supports the complex developmental mechanism of the human face and the varying influence of genetic and environmental factors.

Dose related effects of LPS on endometrial epithelial cell populations from dioestrus cows

Lipopolysaccharides (LPS) from Gram negative bacteria are involved in the pathogeny of uterine diseases in cows. This study aimed to investigate LPS effects on the growth of bovine endometrial epithelial cells (bEEC) and relationships between LPS response and tissue characteristics. Uteri from 35 females were characterized for parity and stage of oestrous cycle. Densities of glandular tissue (dGT), CD11b+ cells and Ki67+ cells were measured in the endometrial tissue. Cells from 13 dioestrus cows were exposed to 0, 2, 4, 8, 12, 16 or 24μg/mL LPS. Effects of parity and stage of the oestrous cycle on tissue characteristics and effects of LPS dosage, cow and tissue characteristics on changes in cell numbers were analyzed by ANOVA. The dGT was higher in metoestrus and dioestrus samples than in pro-oestrus ones whereas densities of CD11b+ and Ki67+ cells were higher at pro-oestrus (p<0.05–p<0.01). LPS influenced bEEC populations in a dose related manner. An increase in number of live cells was observed for dosages ranging from 2 to 12μg/mL LPS (p<0.0001 vs controls). No effect was found on numbers and frequencies of dead cells. With higher dosages, the numbers of live cells did not increase but the numbers of dead did increase. No relationships were observed between cow or tissue characteristics and growth patterns or frequencies of viable bEEC in controls nor in the response to LPS. To conclude this model is suitable for further studies on dysregulations induced by LPS in endometrial tissue.

Tissue composition and allometric growth of tissues from commercial cuts and carcass of Texel lambs slaughtered with different weights

In this study, we evaluated the tissue composition, the ratios between different issues, and the allometric growth of tissues from the commercial cuts neck, shoulder, rib, and leg, and of the carcass of Texel lambs. Thirty uncastrated male lambs born from single calvings were used in this experiment. Lambs were weaned, confined individually, and distributed into five treatments with six replications. Each treatment consisted of a predefined slaughter weight (T23 – initial slaughter, T25, T30, T35, and T40). The proportion of bone decreased linearly in the shoulder, rib, and legs, but remained constant in the neck. The proportion of muscle decreased in the rib, whereas in the other cuts it remained constant. The percentage of fat increased as the slaughter weight of the lambs was increased, for all cuts. In all cuts and in the carcass, bone and muscle showed early growth (b &amp;lt; 1), whereas fat displayed late growth (b &amp;gt; 1). The proportion of bone decreased and fat increased linearly in the carcass, and the proportion of muscle was not influenced by the slaughter weight of the lambs. The muscle/fat ratio decreased in all cuts, and consequently in the half-carcass, as the slaughter weight was increased. The muscle/ bone ratio increased in the shoulder, rib, leg, and half-carcass, but there was no significant effect on the neck. The bone and muscle tissues showed early growth, whereas the fat had late growth in the different commercial cuts and carcass of Texel lambs. The tissue growth pattern of the shoulder may be representative of the allometric growth of the different carcass tissues. An increase in the slaughter weight of Texel lambs leads to a reduction of the muscle/fat ratio, due to the higher deposition of fat in the carcass of these animals.