Evolutionally dynamic L1 regulation in embryonic stem cells

Mobile elements are important evolutionary forces that challenge genomic integrity. Long interspersed element-1 (L1, also known as LINE-1) is the only autonomous transposon still active in the human genome. It displays an unusual pattern of evolution, with, at any given time, a single active L1 lineage amplifying to thousands of copies before getting replaced by a new lineage, likely under pressure of host restriction factors, which act notably by silencing L1 expression during early embryogenesis. Here, we demonstrate that in human embryonic stem (hES) cells, KAP1 (KRAB [Krüppel-associated box domain]-associated protein 1), the master cofactor of KRAB-containing zinc finger proteins (KRAB-ZFPs) previously implicated in the restriction of endogenous retroviruses, represses a discrete subset of L1 lineages predicted to have entered the ancestral genome between 26.8 million and 7.6 million years ago. In mice, we documented a similar chronologically conditioned pattern, albeit with a much contracted time scale. We could further identify an L1-binding KRAB-ZFP, suggesting that this rapidly evolving protein family is more globally responsible for L1 recognition. KAP1 knockdown in hES cells induced the expression of KAP1-bound L1 elements, but their younger, human-specific counterparts (L1Hs) were unaffected. Instead, they were stimulated by depleting DNA methyltransferases, consistent with recent evidence demonstrating that the PIWI–piRNA (PIWI-interacting RNA) pathway regulates L1Hs in hES cells. Altogether, these data indicate that the early embryonic control of L1 is an evolutionarily dynamic process and support a model in which newly emerged lineages are first suppressed by DNA methylation-inducing small RNA-based mechanisms before KAP1-recruiting protein repressors are selected.     

Ubiquitin targeting of rat muscle proteins during short periods of unloading

AIM: The ubiquitin-proteasome system is known to be involved in many situations leading to skeletal muscle atrophy. However, the cellular mechanisms triggering the atrophic process initiation are still poorly understood. For short periods of rat hindlimb unloading, we assessed the specific ubiquitin targeting of sarcoplasmic or myofibrillar proteins in slow and fast rat muscle types. METHODS: Adult Sprague Dawley rats were randomly assigned to three groups: control, hindlimb-unloaded for 4 days (HU4) and hindlimb-unloaded for 8 days (HU8). In fractionated extracts from soleus (SOL) and Extensor Digitorum Longus (EDL) muscles, the relative contents of free and conjugated ubiquitin were quantified by immunoblotting. RESULTS: Hindlimb unloading of short durations resulted in a preferential atrophy of slow-twitch fibres and bound ubiquitin levels were increased by 37 and 68% in the soleus myofibrillar fraction after respectively 4 and 8 days. The ubiquitin conjugation was shown to principally affect the high molecular weight proteins. Free and conjugated ubiquitin levels remained unchanged in sarcoplasmic fraction from SOL muscle after 8 days HU. For the fast muscle (EDL), ubiquitin contents were approximately twofold lower in control conditions, and did not significantly change during the hindlimb unloading periods considered. CONCLUSION: The postural SOL muscle was shown to contain higher constitutive sarcoplasmic ubiquitin levels than the phasic EDL. The high response to unloading of the slow twitch fibres rich SOL muscle was accompanied by a specific conjugation of its myofibrillar proteins that may participate in the initiation of skeletal muscle remodelling consequent to disuse.     

The narrative approach as an effective single intervention in functional somatic symptoms in a multi-disciplinary referral clinic for primary care frequent attenders

Mental health problems are underdiagnosed in general practice, primarily because they are often somatized and the patient reports only physical symptoms. These somatized symptoms are responsible for a large percentage of the frequent attenders in general practice. Palpitations are among those somatized symptoms. Here we present the theoretical background and the process of assessment and treatment of patients referred to a special counselling clinic for frequent attenders, through the report of a patient with palpitations. It illustrates the use of the narrative approach and the possible mode of action of this specific intervention.     

Effect of design interventions on a dementia care setting

This study examined the effects of particular design interventions in a long-term care facility on residents with dementia and staff perceptions of care delivery. Major renovations were carried out in a care facility in the Midwestern United States. Renovations included a new addition of a dementia care unit designed as a cluster of resident rooms around living and dining areas, and two renovated wings with decentralized dining areas. The research methods used in the study included environmental assessment with the Professional Environmental Assessment Protocol (PEAP), behavioral mapping, and focus-group interviews with staff members. The renovated environment scored higher in PEAP and was perceived by the staff members as a more homelike setting. Although behavioral observations indicate that there was more involvement in programmed activities by the residents, the decentralized neighborhood design did not meet all the behavioral expectations due to a lack of appropriate activities, high staff turnover, and family members' resistance to the relocation of their loved ones. Organizational commitment, advanced planning for appropriate staffing levels, and dementia-related training is crucial for fuller realization of the potential of a household design.     

Organic solvents and temperature effects on desorption from immunoadsorbents. DNP-BSA anti-DNP as a model.

Conditions for desorbing a DNP carrier from its immunoadsorbent were studied in various hydro-organic media at different pHs and temperatures, including the sub-zero range. It appeared that DNP--anti-DNP interaction is the result of a balance between various bonds and the best result (95% yield) was obtained in hydro-organic solvent at high pH and +30 degrees C.     

Incidental Diagnosis of Intradural Lumbar Disc Herniation During Discography: A Case Report

▪ Abstract:   We describe an incidental finding of intradural lumbar disc herniation diagnosed radiographically during discography. A patient was referred to our center for discography with symptoms of worsening, intractable low back pain radiating to both hips and the left leg which was exacerbated when standing and walking. Magnetic resonance imaging of the lumbar spine revealed multiple disc bulges and lumbar facet arthroses with ligamentum flavum hypertrophy producing moderate central canal and lateral recess stenosis. Discography was performed at three levels (L3-4, L4-5, L5-S1). During fluoroscopically guided injection into L4-5 it was noted that contrast was not contained within the disc and spread intrathecally with a myelographic appearance. Computerized tomography confirmed accurate needle placement and a spread of contrast into the intrathecal space. To the best of our knowledge, this is the first report describing a finding of intradural disc herniation while performing discography. Physicians should be aware of this potential finding while performing this technique. ▪