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Skeletal development is a tightly regulated process that primarily occurs through two distinct mechanisms. In intramembranous ossification, mesenchymal progenitors condense and transdifferentiate directly into osteoblasts, giving rise to the flat bones of the skull. The majority of the skeleton develops through endochondral ossification, in which mesenchymal progenitors give rise to a cartilaginous template that is gradually replaced by bone. The study of these processes necessitates a suitable animal model, a requirement to which the mouse is admirably suited. Their rapid reproductive ability, developmental and physiologic similarity to humans, and easily manipulated genetics all contribute to their widespread use. Outlined here are the most common histological and immunohistochemical techniques utilized in our laboratory for the isolation and analysis of specimens from the developing murine skeleton.Cartilage is a connective tissue presenting in several forms that are all essential components of the vertebrate skeleton. Complementing in vivo models, cultures of its resident cells-chondrocytes-are important experimental models in mechanistic and preclinical studies relevant to skeletal development and adult homeostasis and to such human pathologies as chondrodysplasias and osteoarthritis. Both growth plate and articular chondrocytes produce pancartilaginous extracellular matrix components, but the two cell subtypes also have distinct phenotypic properties that account for different structural features, functions, and fates of their tissues. Based on study goals, primary chondrocyte cultures should therefore be established from either growth plate or articular cartilage. Here, we describe the methods used in our laboratory to isolate and culture growth plate and articular chondrocytes from neonatal and adult mice, respectively. Both methods involve manual and enzymatic procedures to clean cartilage samples from contaminating tissues and to release chondrocytes as single-cell suspensions from their cartilage matrix.Cartilage is a specialized skeletal tissue with a unique extracellular matrix elaborated by its resident cells, chondrocytes. The tissue presents in several forms, including growth plate and articular cartilage, wherein chondrocytes follow a differential differentiation program and have different fates. The induction of gene modifications in cartilage specifically relies on mouse transgenes and knockin alleles taking advantages of transcriptional elements primarily active in chondrocytes at a specific differentiation stage or in a specific cartilage type. These transgenes/alleles have been widely used to study the roles of specific genes in cartilage development, adult homeostasis, and pathology. As cartilage formation is critical for postnatal life, the inactivation or significant alteration of key cartilaginous genes is often neonatally lethal and therefore hampers postnatal studies. Gold standard approaches to induce postnatal chondrocyte-specific gene modifications include the Cre-loxP and Tet-ON/OFF systems. Selecting the appropriate promoter/enhancer sequences to drive Cre expression is of crucial importance and determines the specificity of conditional gain- or loss-of-function models. selleck chemical In this chapter, we discuss a series of transgenes and knockin alleles that have been developed for gene manipulation in cartilage and we compare their expression patterns and efficiencies.Chondrons are the main functional microanatomical units in cartilage, consisting of chondrocytes and the directly surrounding pericellular matrix (PCM). They have attracted attention as a more physiological and biomimetic in vitro model for evaluating chondrocyte function and metabolism as compared to single chondrocytes. Chondrons may be more suitable for in vitro studies than primary chondrocytes that have been isolated without PCM since their in situ and in vivo states remain intact chondrocytes within their PCM do not undergo the rapid dedifferentiation that proliferating single chondrocytes undergo in culture. Therefore, chondrons may be a better model for studying chondrocyte biology and responses to pro-inflammatory and anti-inflammatory cytokines, growth factors and novel therapeutics. In this chapter, we present a concise and unified protocol for enzymatic isolation of intact chondrons from human articular cartilage and determination of their viability.Chondrocytes are the only cell type in cartilage. The dense cartilage extracellular matrix surrounding the chondrocytes makes isolating these cells a complex and lengthy task that subjects the cells to harsh conditions. Protocols to isolate expand and maintain these cells have been improved over the years, providing ways to obtain viable cells for tissue engineering and clinical applications. Here we describe a method to obtain populations of chondrocytes that are able to expand and maintain a native-like phenotype.It is unclear if the results of randomised controlled trials (RCTs) of behaviour therapy (BT) for Tourette syndrome (TS) and chronic tic disorder (CTD) can be generalised to naturalistic clinical settings and are durable long-term. In this naturalistic study, 74 young people with TS/CTD received BT at a specialist clinic. Data were collected at baseline, post-treatment, and at 3-, 6-, and 12-month follow-ups. Measures included the Yale Global Tic Severity Scale (YGTSS) and the Clinical Global Impression-Improvement scale (CGI-I), amongst others. Tic severity and tic-related impairment improved after treatment, with large within-group effect sizes. At post-treatment, 57% of the participants were classified as treatment responders according to the CGI-I. Tic severity and tic-related impairment improved further through the follow-up, with 75% treatment responders at the 12-month follow-up. BT is an effective and durable treatment for young people with TS/CTD in a naturalistic specialist clinical setting, with comparable effects to RCTs.

Cellular senescence and fibrosis are important phenomena in the development of heart failure (HF). These processes are closely related to telomeric length (TL).

To assess cellular senescence in HF through the study of TL in peripheral blood mononuclear cells (PBMCs).

Using real-time PCR, TL was measured in PBMCs from 20 patients diagnosed with HF, aged between 51 and 77years (50% males). Ten patients had HF with reduced ejection fraction (HFrEF) and ten had preserved EF (HFpEF). TL was measured in 20 healthy controls matched by age and gender. Obtained values were compared with an internal control, the 36B4 gene, which never modifies its expression, and correlated with the clinical parameters.

TL mean was 1327 in patients with HF (95% CI 1309-1344) compared to 1286 (95% CI 1264-1308) in controls (p = 0.005). No differences were found when studying the correlation of telomere size with subgroups by gender, left ventricle ejection fraction (LVEF), presence of ischemic heart disease, smoking, Chronic Obstructive Pulmonary Disease (COPD), NYHA stage, degree of renal function or number of hospital admissions in the previous year.