Solitons in Yakushevich-like models of DNA dynamics with improved intrapair potential

The Yakushevich (Y) model provides a very simple pictures of DNA torsion dynamics, yet yields remarkably correct predictions on certain physical characteristics of the dynamics. In the standard Y model, the interaction between bases of a pair is modelled by a harmonic potential, which becomes anharmonic when described in terms of the rotation angles; here we substitute to this different types of improved potentials, providing a more physical description of the H-bond mediated interactions between the bases. We focus in particular on soliton solutions; the Y model predicts the correct size of the nonlinear excitations supposed to model the ``transcription bubbles'', and this is essentially unchanged with the improved potential. Other features of soliton dynamics, in particular curvature of soliton field configurations and the Peierls-Nabarro barrier, are instead significantly changed

Multi-site H-bridge breathers in a DNA--shaped double strand

We investigate the formation process of nonlinear vibrational modes representing broad H-bridge multi--site breathers in a DNA--shaped double strand. Within a network model of the double helix we take individual motions of the bases within the base pair plane into account. The resulting H-bridge deformations may be asymmetric with respect to the helix axis. Furthermore the covalent bonds may be deformed distinctly in the two backbone strands. Unlike other authors that add different extra terms we limit the interaction to the hydrogen bonds within each base pair and the covalent bonds along each strand. In this way we intend to make apparent the effect of the characteristic helicoidal structure of DNA. We study the energy exchange processes related with the relaxation dynamics from a non-equilibrium conformation. It is demonstrated that the twist-opening relaxation dynamics of a radially distorted double helix attains an equilibrium regime characterized by a multi-site H-bridge breather.Comment: 27 pages and 10 figure

Diagnosing congenital Cytomegalovirus infection: Don't get rid of dried blood spots

Background: Congenital Cytomegalovirus (cCMV) is a serious global public health issue that can cause irreversible fetal and neonatal congenital defects in symptomatic or asymptomatic newborns at birth. In absence of universal cCMV screening, the retrospective diagnosis of cCMV infection in children is only possible by examining Dried Blood Spot (DBS) samples routinely collected at birth and stored for different time spans depending on the newborn screening regulations in force in different countries. In this article, we summarize the arguments in favor of long-term DBS sample storage for detecting cCMV infection. Main text: CMV infection is the most common cause of congenital infection resulting in severe defects and anomalies that can be apparent at birth or develop in early childhood. Sensorineural hearing loss is the most frequent consequence of cCMV infection and may have a late onset and progress in the first years of life. The virological diagnosis of cCMV is essential for clinical research and public health practices. In fact, in order to assess the natural history of CMV infection and distinguish between congenital or acquired infection, children should be diagnosed early by analyzing biological samples collected in the first weeks of life (3 weeks by using viral culture and 2 weeks by molecular assays), which, unfortunately, are not always available for asymptomatic or mildly symptomatic children. It now seems possible to overcome this problem since the CMV-DNA present in the blood of congenitally infected newborns can be easily retrieved from the DBS samples on the Guthrie cards routinely collected and stored within 3 days from birth in the neonatal screening program for genetic and congenital diseases. Early collection and long-term storage are inexpensive methods for long-term bio-banking and are the key points of DBS testing for the detection of cCMV. Conclusion: DBS sampling is a reliable and inexpensive method for long-term bio-banking, which enables to diagnose known infectious diseases - including cCMV - as well as diseases not jet recognized, therefore their storage sites and long-term storage conditions and durations should be the subject of political decision-making

A sunlit skin

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An adolescent with recurrent ankle swelling

A 14-year-old girl was admitted to our institute with a history of intermittent bilateral ankle swelling, and moderate but progressively worsening pain which has lasted for 2 years. The patient's history was unremarkable. She did not take medications and was not involved in any sports activity. She reported no fever, gastrointestinal symptoms, fatigue, weight loss, travels abroad or previous infections. She reported moderate pain at night, associated with a sense of heaviness, tightness and general discomfort, and with no response to ibuprofen. Physical examination was remarkable only for bilateral ankle non-pitting oedema, more evident on the left leg, with a thickened skinfold at the base of the second toe, and without redness, swelling or skin warming. The patient had been previously examined, and her foot and ankle X-rays, ultrasound (US) and MRI were all negative. Blood tests (white cell count, C reactive protein, erythrocyte sedimentation rate, albumin, antinuclear antibodies, creatinine, transaminase, creatine kinase, lactate dehydrogenase, thyroid function and glucose) and urinalysis were in the normal range. Her ocular assessment and echocardiogram were also normal. Question 1: Based on the clinical picture and laboratory tests, what is the most likely diagnosis? Deep venous thrombosis. Osteochondritis. Lymphoedema. Juvenile idiopathic arthritis. Question 2: Based on what you see infigure 1, what is the underlying cause? Recurrent bacterial lymphangitis. Primary lymphoedema. Tumour. Filariasis. Figure 1 Lymphoscintigraphy of the lower extremities showing insufficient deep lymphatic circulation in the left leg (red arrow, A) replaced by superficial drainage (B). Question 3: Which is the best diagnostic test to confirm the diagnosis? US scan. MRI. Lymphoscintigraphy. Reassurance and clinical follow-up. Question 4: What is the mainstay of management of this condition? Wait and see. Antibiotic course. Supportive therapy (ie, physical activity, elevation of extremities, pneumatic compression). Surgical intervention. Answers can be found on page 2

Don't just look at the surface: When mucosa tells more than the skin

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Impact of the first COVID-19 lockdown on the relationship with parents and peers in a cohort of adolescents with somatic symptom disorder

To investigate the coping strategies of a group of adolescents with somatic symptom disorder compared to non-somatic symptom disorder peers during the COVID-19 related lockdown.This cross-sectional study is the second part of a previously published study showing an improved trend in depression and anxiety in a group of patients with somatic symptom disorder compared to non-somatic symptom disorder peers. An anonymous semi-structured survey was distributed to two groups of Italian adolescents to measure the impact of quarantine on their daily life and coping strategies.We recruited 115 adolescents, 58 (50.4%) mean age 15.3, with a recent diagnosis of somatic symptom disorder and 57 (49.6%) mean age 15.8, control peers.The aim of this study was to detect differences in coping strategies and relationships with parents and peers, during the lockdown period in a group of adolescents with somatic symptom disorder and low disease burden when compared with a non-somatic symptom disorder group.The relationship with parents significantly worsened in 4 (6.9%) of adolescents with somatic symptom disorder compared to 12 (21.1%) adolescents in the non-somatic symptom disorder group (p = 0.048). The relationship with peers significantly improved in 13 (22.4%) of adolescents with symptom disorder versus 3 (5.3%) of peers of the non- somatic symptom disorder group (p = 0.013).Adolescents with somatic symptom disorder with a low burden of physical symptoms experienced less deterioration in their relationships with parents and peers than the non-somatic symptom disorder group

Morphological and organic spectroscopic studies of a 44-million-year-old leaf beetle (Coleoptera: Chrysomelidae) in amber with endogenous remains of chitin

This study details the quality of preservation of amber deposits in the Eocene. Through Baltic amber crack-out studies using Synchrotron Micro-Computed Tomography and Scanning Electron Microscopy it was found that the cuticle of a specimen of leaf beetle (Crepidodera tertiotertiaria (Alticini: Galerucinae: Chrysomelidae)) is exceptionally well preserved. Spectroscopic analysis using Synchrotron Fourier Transform Infrared Spectroscopy suggests presence of degraded α -chitin in multiple areas of the cuticle, and Energy Dispersive Spectroscopy supports the presence of organic preservation. This remarkable preservation is likely the result of several factors such as the favourable antimicrobial and physical shielding properties of Baltic amber as compared to other depositional media, coupled to rapid dehydration of the beetle early in its taphonomic process. We provide evidence that crack-out studies of amber inclusions, although inherently destructive of fossils, are an underutilised method for probing exceptional preservation in deep time

Early introduction oral immunotherapy for IgE-mediated cow's milk allergy: A follow-up study confirms this approach as safe and appealing to parents

Introduction: Early introduction oral immunotherapy (E-OIT) in the first year of life can be a safe treatment for infants with cow's milk allergy (CMA). Once the protocol is completed, doubts remain whether children achieve tolerance or remain desensitized. According to current guidelines, this is determined by an avoidance period followed by a re-exposure to the food allergen during an in-hospital oral food challenge (OFC). In real life, this approach can be complicated, time-consuming, and anxiety-provoking for parents. We assessed the long-term safety of E-OIT for CMA in a cohort of children who switched to an unrestricted diet without testing the achievement of tolerance at the end of the OIT protocol. Materials and Methods: We performed a descriptive analysis of the clinical follow-up of a cohort of children diagnosed with IgE-mediated CMA and undergoing E-OIT protocol in their first year of life. In a previous publication, the same cohort of patients had been studied to assess the feasibility of E-OIT for CMA. In the present study, we reported the results of a telephone survey, carried out through a questionnaire to their families enquiring about milk consumption and other ongoing atopic conditions of children. Results: After an average of 4 years from the start of E-OIT, 62/73 patients (85% of the historical cohort) participated in the survey. Among them, all 56 patients who had previously successfully completed the protocol reported an unrestricted cow's milk intake. Ninety–three percent of these children did not experience any further allergic reactions, while the remaining 7% described only mild and transitory reactions until the 6-month period after the end of the protocol. Conclusions: This study confirmed the long-term safety of E-OIT for CMA and challenged the paradigm of the need for allergen food withdrawal to discern between desensitization and tolerance. It could be a starting point for planning future trials on this issue