Tenascin distribution in articular cartilage from normal subjects and from patients with osteoarthritis and rheumatoid arthritis

Objective. To determine whether tenascin is present in normal and diseased human cartilage. Methods. Immunohistochemical and biochemical assays with a monoclonal antibody against all tenascin isoforms (BC-4) were used. Results. Cartilage samples from osteoarthritis and rheumatoid arthritis patients contained increased amounts of tenascin compared with the levels in normal cartilage. Human fetal cartilage was also found to contain tenascin. In normal cartilage explants treated with interleukin-1β, tenascin was present in pericellular areas of all layers. Immunolocalization studies revealed that tenascin was most abundant in the superficial layers of osteoarthritic cartilage. Western blot analysis performed from dissociative extracts of diseased cartilage confirmed the presence of subunits of the native molecule. Conclusion. Tenascin is increased in arthritic cartilage and is weakly expressed in normal cartilage.     

COVID‐19 lockdown consequences on body mass index and perceived fragility related to physical activity: A worldwide cohort study

BackgroundThis paper is a follow‐up study continuing the COVISTRESS network previous research regarding health‐related determinants.ObjectiveThe aim was to identify the main consequences of COVID‐19 lockdown on Body Mass Index and Perceived Fragility, related to Physical Activity (PA), for different categories of populations, worldwide.DesignThe study design included an online survey, during the first wave of COVID‐19 lockdown, across different world regions.Setting and participantsThe research was carried out on 10 121 participants from 67 countries. The recruitment of participants was achieved using snowball sampling techniques via social networks, with no exclusion criteria other than social media access.Main outcome measures Body Mass Index, Physical Activity, Perceived Fragility and risk of getting infected items were analysed. SPSS software, v20, was used. Significance was set at P < .05.Results Body Mass Index significantly increased during lockdown. For youth and young adults (18‐35 years), PA decreased by 31.25%, for adults (36‐65 years) by 26.05% and for the elderly (over 65 years) by 30.27%. There was a high level of Perceived Fragility and risk of getting infected for female participants and the elderly. Correlations between BMI, Perceived Fragility and PA were identified.Discussion and ConclusionsThe research results extend and confirm evidence that the elderly are more likely to be at risk, by experiencing weight gain, physical inactivity and enhanced Perceived Fragility. As a consequence, populations need to counteract the constraints imposed by the lockdown by being physically active.     

Malignant melanoma in HIV: Epidemiology,pathogenesis, and management

People affected by immunodeficiency, and especially those infected by HIV, are burdened by a higher risk of developing malignancies. It has been estimated that the incidence of melanoma in HIV‐infected people is 2.6‐fold higher than in uninfected ones. In this group of patients, melanoma shows a more aggressive phenotype and poorer survival rates compared to HIV‐negative people. Standard guidelines of diagnosis and care do not exist yet. Studies suggest high index of suspicion and a low threshold for biopsy in HIV‐positive patients regardless of their CD4⁺ count and the use of standard surgical margins for re‐excision procedures. In case of diagnosis of melanoma in HIV‐positive patients, a thorough search for metastatic disease is recommended because of the more aggressive course of this cancer in HIV‐positive patients. Moreover, to rapidly find out any recurrence or metastatic disease after treatment, these patients need a close follow‐up, every 3 months, for the first 2 years and at least twice yearly thereafter. Although surgery remains the main therapeutic option, application of immune checkpoint‐based immunotherapy is being studied and seems to be promising. The aim of this review is to present the current knowledge and future options for melanoma diagnosis and treatment in people living with HIV.     

Perceptual rivalry across animal species

This review in memoriam of Jack Pettigrew provides an overview of past and current research into the phenomenon of multistable perception across multiple animal species. Multistable perception is characterized by two or more perceptual interpretations spontaneously alternating, or rivaling, when animals are exposed to stimuli with inherent sensory ambiguity. There is a wide array of ambiguous stimuli across sensory modalities, ranging from the configural changes observed in simple line drawings, such as the famous Necker cube, to the alternating perception of entire visual scenes that can be instigated by interocular conflict. The latter phenomenon, called binocular rivalry, in particular caught the attention of the late Jack Pettigrew, who combined his interest in the neuronal basis of perception with a unique comparative biological approach that considered ambiguous sensation as a fundamental problem of sensory systems that has shaped the brain throughout evolution. Here, we examine the research findings on visual perceptual alternation and suppression in a wide variety of species including insects, fish, reptiles, and primates. We highlight several interesting commonalities across species and behavioral indicators of perceptual alternation. In addition, we show how the comparative approach provides new avenues for understanding how the brain suppresses opposing sensory signals and generates alternations in perceptual dominance.     

Why considering sexual differences is necessary when studying encephalopathy of prematurity through rodent models

Preterm birth is a high‐risk factor for the development of gray and white matter abnormalities, referred to as “encephalopathy of prematurity,” that may lead to life‐long motor, cognitive, and behavioral impairments. The prevalence and clinical outcomes of encephalopathy of prematurity differ between sexes, and elucidating the underlying biological basis has become a high‐priority challenge. Human studies are often limited to assessment of brain region volumes by MRI, which does not provide much information about the underlying mechanisms of lesions related to very preterm birth. However, models using KO mice or pharmacological manipulations in rodents allow relevant observations to help clarify the mechanisms of injury sustaining sex‐differential vulnerability. This review focuses on data obtained from mice aged P1–P5 or rats aged P3 when submitted to cerebral damage such as hypoxia‐ischemia, as their brain lesions share similarities with lesion patterns occurring in very preterm human brain, before 32 gestational weeks. We first report data on the mechanisms underlying the development of sexual brain dimorphism in rodent, focusing on the hippocampus. In the second part, we describe sex specificities of rodent models of encephalopathy of prematurity (RMEP), focusing on mechanisms underlying differences in hippocampal vulnerability. Finally, we discuss the relevance of these RMEP. Together, this review highlights the need to systematically search for potential effects of sex when studying the mechanisms underlying deficits in RMEP in order to design effective sex‐specific medical interventions in human preterms.