Atomic Force Microscopy of Viruses.

Atomic force microscopy employs a nanometric tip located at the end of a micro-cantilever to probe surface-mounted samples at nanometer resolution. Because the technique can also work in a liquid environment it offers unique possibilities to study individual viruses under conditions that mimic their natural milieu. Here, we review how AFM imaging can be used to study the surface structure of viruses including that of viruses lacking a well-defined symmetry. Beyond imaging, AFM enables the manipulation of single viruses by force spectroscopy experiments. Pulling experiments can provide information about the early events of virus-host interaction between the viral fibers and the cell membrane receptors. Pushing experiments measure the mechanical response of the viral capsid and its contents and can be used to show how virus maturation and exposure to different pH values change the mechanical response of the viruses and the interaction between the capsid and genome. Finally, we discuss how studying capsid rupture and self-healing events offers insight in virus uncoating pathways.

The 2018 correlative microscopy techniques roadmap.

Developments in microscopy have been instrumental to progress in the life sciences, and many new techniques have been introduced and led to new discoveries throughout the last century. A wide and diverse range of methodologies is now available, including electron microscopy, atomic force microscopy, magnetic resonance imaging, small-angle x-ray scattering and multiple super-resolution fluorescence techniques, and each of these methods provides valuable read-outs to meet the demands set by the samples under study. Yet, the investigation of cell development requires a multi-parametric approach to address both the structure and spatio-temporal organization of organelles, and also the transduction of chemical signals and forces involved in cell-cell interactions. Although the microscopy technologies for observing each of these characteristics are well developed, none of them can offer read-out of all characteristics simultaneously, which limits the information content of a measurement. For example, while electron microscopy is able to disclose the structural layout of cells and the macromolecular arrangement of proteins, it cannot directly follow dynamics in living cells. The latter can be achieved with fluorescence microscopy which, however, requires labelling and lacks spatial resolution. A remedy is to combine and correlate different readouts from the same specimen, which opens new avenues to understand structure-function relations in biomedical research. At the same time, such correlative approaches pose new challenges concerning sample preparation, instrument stability, region of interest retrieval, and data analysis. Because the field of correlative microscopy is relatively young, the capabilities of the various approaches have yet to be fully explored, and uncertainties remain when considering the best choice of strategy and workflow for the correlative experiment. With this in mind, the Journal of Physics D: Applied Physics presents a special roadmap on the correlative microscopy techniques, giving a comprehensive overview from various leading scientists in this field, via a collection of multiple short viewpoints.

Angioimmunoblastic T-cell lymphoma with a clonal plasma cell proliferation that underwent immunoglobulin isotype switch in the skin, coinciding with cutaneous disease progression.

Plasma cell proliferations in specific cutaneous lesions of angioimmunoblastic T-cell lymphoma(AITL) are very uncommon. Here, we report a case of clonal plasma cell proliferation in skin with heavy-chain-immunoglobulin-isotype-switch after cutaneous disease progression. Histopathologically, initial plaque lesions were suggestive of marginal-zone B-cell-lymphoma. Nevertheless, this 77-year-old lady was diagnosed with AITL after the progression of skin lesions from plaques to nodular tumors. A lymph node biopsy confirmed the diagnosis. Both cutaneous specimens showed a polymorphic cellular infiltrate with atypical T-cell-lymphocytes arranged in a pseudonodular pattern that expressed CD3, PD1 and BCL6, with patchy expression of CD30. Interestingly, a slight IgG-Lambda plasma cell component was seen at the periphery of the infiltrate in the first specimen which increased in number in the later nodular lesion, showing not only Lambda light chain restriction and IgG but also IgG4. PCR studies for IgH and TCR genes showed an IgH clonal peak on both skin lesions but not on lymph node biopsy. On the contrary, the same clonal TCR peak was found in the three specimens. Neoplastic follicular helper T-cells within cutaneous-specific microenvironment could be responsible for the modulation of the immunoglobulin isotype class switch change. Further studies are needed to support this hypothesis.

[Translated article] Effects of duroplasty with bovine pericardium on fibrosis and extent of spinal cord injury: An experimental study in pigs.

INTRODUCTION: Traumatic spinal cord injury (SCI) leads to increased intraspinal pressure that can be prevented by durotomy and duroplasty. The aim of the study was to evaluate fibrosis and neural damage in a porcine model of SCI after duroplasty and application of hyaluronic acid (HA) in the tissue cavity. MATERIALS AND METHODS: Experimental study. We created a porcine SCI model by durotomy and spinal cord hemisection of a cervical segment (1cm). Six pigs (Sus scrofa domestica) were used to evaluate three surgical scenarios: (1) control injury with dural reparative microsurgery, (2) duroplasty using bovine pericardium (BPD), and (3) previous method plus HA applied at the lesion. Animals were sacrificed one-month post-injury to assess fibrotic responses and neural tissue damage using conventional histological and immunohistochemical methods. RESULTS: In the control case, dural suture prevented invasion of the lesion by extradural connective tissue, and the dura mater showed a 1-mm thickening in the perilesional area. The bovine pericardium patch blocked the entrance of extradural connective tissue, decreased dura-mater tension, and satisfactorily integrated within the receptor tissue. However, it also enhanced subdural and perilesional fibrosis, which was not inhibited by filling the lesion cavity with low- or high-molecular-weight HA. CONCLUSIONS: Duroplasty prevents collapse of the dura-mater over the spinal cord tissue, as well as invasion of the lesion by extramedullary fibrotic tissue, without creating additional neural damage. Nevertheless, it enhances the fibrotic response in the spinal cord lesion and the perilesional area. Additional antifibrotic strategies are needed to facilitate spinal cord repair.

Effects of duroplasty with bovine pericardium on fibrosis and extent of spinal cord injury: An experimental study in pigs. / Efecto de la reparación de la duramadre con pericardio bovino sobre la fibrosis y la extensión de la lesión medular: estudio experimental en cerdos.

INTRODUCTION: Traumatic spinal cord injury (SCI) leads to increased intraspinal pressure that can be prevented by durotomy and duroplasty. The aim of the study was to evaluate fibrosis and neural damage in a porcine model of SCI after duroplasty and application of hyaluronic acid (HA) in the tissue cavity. MATERIALS AND METHODS: Experimental study. We created a porcine SCI model by durotomy and spinal cord hemisection of a cervical segment (1cm). Six pigs (Sus scrofa domestica) were used to evaluate three surgical scenarios: (1)control injury with dural reparative microsurgery, (2)duroplasty using bovine pericardium (BPD), and (3)previous method plus HA applied at the lesion. Animals were sacrificed one-month post-injury to assess fibrotic responses and neural tissue damage using conventional histological and immunohistochemical methods. RESULTS: In the control case, dural suture prevented invasion of the lesion by extradural connective tissue, and the dura mater showed a 1-mm thickening in the perilesional area. The bovine pericardium patch blocked the entrance of extradural connective tissue, decreased dura-mater tension, and satisfactorily integrated within the receptor tissue. However, it also enhanced subdural and perilesional fibrosis, which was not inhibited by filling the lesion cavity with low- or high-molecular-weight HA. CONCLUSIONS: Duroplasty prevents collapse of the dura-mater over the spinal cord tissue, as well as invasion of the lesion by extramedullary fibrotic tissue, without creating additional neural damage. Nevertheless, it enhances the fibrotic response in the spinal cord lesion and the perilesional area. Additional antifibrotic strategies are needed to facilitate spinal cord repair.

The capillarity of nanometric water menisci confined inside closed-geometry viral cages.

We present an investigation of water menisci confined in closed geometries by studying the structural effects of their capillary forces on viruses during the final stage of desiccation. We used individual particles of the bacteriophage phi29 and the minute virus of mice. In both cases the genomic DNA was ejected from the capsid. However, although the structural integrity of the minute virus of mice was essentially preserved, the phi29 capsid underwent a wall-to-wall collapse. We provide evidence that the capillary forces of water confined inside the viruses are mainly responsible for these effects. Moreover, by performing theoretical simulations with a lattice gas model, we found that some structural differences between these 2 viruses may be crucial to explain the different ways in which they are affected by water menisci forces confined at the nanoscale.

[Celedonio Calatayud-Costa and the birth of the specialty, the Spanish Society of Medical Radiology, and the journal: the beginning of a century of Spanish radiology]. / Celedonio Calatayud Costa y el nacimiento de la especialidad, la Sociedad Española de Radiología Médica y la revista: el comienzo de un siglo de Radiología española.

Dr. Celedonio Calatayud-Costa, an eminent Spanish radiologist, electrical engineer, researcher, and co-founder of the Spanish Society of Electrical Engineering and Medical Radiology, was also the founder of the Spanish Journal of Electrical Engineering and Medical Radiology. The journal, the first journal dedicated specifically to the incipient specialty of electrology, from which radiology would later develop, was the official publication of that primordial Society, and was thus the first antecessor of Radiología, which is today the official journal of the Spanish Society of Medical Radiology. This article analyzes the figure of Dr. Calatayud, based on the scant information available about him, in the centennial of the publication of his journal. Criticized by some and eulogized by others, knowledge about this controversial figure is essential to any understanding of the beginnings of the specialty and its scientific publication in Spain.

Built-in mechanical stress in viral shells.

Mechanical properties of biological molecular aggregates are essential to their function. A remarkable example are double-stranded DNA viruses such as the φ29 bacteriophage, that not only has to withstand pressures of tens of atmospheres exerted by the confined DNA, but also uses this stored elastic energy during DNA translocation into the host. Here we show that empty prolated φ29 bacteriophage proheads exhibit an intriguing anisotropic stiffness which behaves counterintuitively different from standard continuum elasticity predictions. By using atomic force microscopy, we find that the φ29 shells are approximately two-times stiffer along the short than along the long axis. This result can be attributed to the existence of a residual stress, a hypothesis that we confirm by coarse-grained simulations. This built-in stress of the virus prohead could be a strategy to provide extra mechanical strength to withstand the DNA compaction during and after packing and a variety of extracellular conditions, such as osmotic shocks or dehydration.

Smoke exposure as a determinant of autoantibody titre in α1-antitrypsin deficiency and COPD.

Liberation of elastin peptides from damaged lung may be a mechanism of autoimmune lung disease. Citrullination, and anti-citrullinated protein antibody formation occurs in smokers, but the role of smoking in autoantibody generation relevant to pulmonary disease is unclear. Anti-elastin, anti-cyclic citrullinated peptide (anti-CCP) and anti-mutated citrullinated vimentin (anti-MCV) antibodies were measured in 257 subjects with α1-antitrypsin deficiency (AATD), 113 subjects with usual chronic obstructive pulmonary disease (COPD) and 22 healthy nonsmokers. Levels were compared between groups, against phenotypic features and against smoke exposure. Anti-elastin antibodies were higher in controls relative to AATD (p = 0.008) and usual COPD (p < 0.00001), and in AATD relative to usual COPD (p < 0.00001). Anti-elastin levels showed a threshold at 10 pack-yrs, being higher in those who had smoked less (p = 0.004). No relationships between antibody levels and clinical phenotype were seen after adjustment for smoke exposure. Anti-CCP antibodies were higher in usual COPD than AATD (p = 0.002) but the relationship to smoke exposure was less clear. Smoke exposure is the main determinant of anti-elastin antibody levels, which fall after 10 pack-yrs. Local antibody complexes may be a better measure of elastin directed autoimmunity than circulating levels.

The supporting role of the teres major muscle, an additional component in glenohumeral stability? An anatomical and radiological study.

Muscle coordination plays an important role in glenohumeral stability. The rotator cuff and the long head of the biceps are considered the primary dynamic stabilizers muscles. However, the fact that a subgroup of patients with a massive tear in the rotator cuff were able to keep a normal function, should make us question this traditional view. We hypothesize that the teres major which is also a monoarticular scapulohumeral muscle, although it is not part of the conjoined tendon of the rotator cuff, can play a role in glenohumeral stability by a direct support of the humeral head generated by the particular posteroanterior location of this muscle under the humeral head and which, as far as we know, has not been written up previously. This particular effect could appear while the arm is being lifted and the humeral head could be leaning on against the teres major muscle belly underneath it. An anatomical a radiological study was carried out to substantiate our hypothesis. Two cadaver specimens were used for the anatomical study. Frist body was studied through conventional dissection. The second body was analysed through sectional anatomy. Then a radiological study was carried out using magnetic resonance imaging in a healthy male volunteer. Both anatomically and radiologically, the anteroinferior surface of the humeral head was showed firmly resting against the muscle belly of the teres major, to the point of misshaping it from 110 degrees of arm elevation with external rotation. The specific contribution of this effect to the glenohumeral stability needs to be confirmed by further studies and can help us to prevent the high incidence of glenohumeral dislocations.

[Utility of bone SPECT-CT in percutaneous vertebroplasty]. / Utilidad de la SPECT-TAC ósea en la vertebroplastia percutánea.

Percutaneous vertebroplasty is a minimally invasive procedure that has shown excellent results in the treatment of back pain due to acute-subacute vertebral fracture. The bone scintigraphy shows the increase of metabolic exchange in the fracture. The new hybrid SPECT-CT equipment combines bone SPECT images with Computed Tomography (CT), making it possible to obtain more combined, functional and anatomical information. We present 5 selected patients studied by bone SPECT-CT in whom fused images made it possible to obtain a more precise localization of the pain origin, and thus assess other possible causes of the vertebral pain or even reassess the vertebroplasty indication.

Attitudes towards Oral Health in Patients with Rheumatoid Arthritis: A Qualitative Study Nested within a Randomized Controlled Trial.

INTRODUCTION: Patients with rheumatoid arthritis (RA) present a higher incidence and severity of periodontitis than the general population. Our study, Outcomes of Periodontal Treatment in Patients with Rheumatoid Arthritis (OPERA), was a randomized waiting-list controlled trial using mixed methods. Patients randomized to the intervention arm received intensive periodontal treatment, and those in the control arm received the same treatment with a 6-mo delay. AIM: The nested qualitative component aimed to explore patients' experiences and priorities concerning oral health and barriers and facilitators for trial participation. METHODS: Using purposive sampling until thematic saturation was reached, we conducted 21 one-to-one semistructured interviews with randomized patients in either of the 2 treatment arms as well as with patients who did not consent for trial participation. RESULTS: The patients described their experiences about RA, oral health, and study participation. Previous experiences with dental care professionals shaped patients' current perceptions about oral health and the place of oral health on their list of priorities compared with other conditions. Patients also highlighted some of the barriers and facilitators for study participation and for compliance with oral health maintenance. The patients, in the control arm, presented their views regarding the acceptable length of waiting time for the intervention. CONCLUSION: The associations between periodontal and systemic health are increasingly recognized by the literature. Our study provided an insight into RA patients' experiences and perceptions about oral health. It also highlighted some of the barriers and facilitators for participating in a periodontal interventional study for this group. We hope that our findings will support the design of larger interventional periodontal studies in patients with RA. The complex challenges faced by the burden of RA and the associated multimorbidities in this patient group might highlight opportunities to improve access to oral health services in this patient population. KNOWLEDGE TRANSFER STATEMENT: This article provided insights into the experiences and perceptions of rheumatoid arthritis patients about their oral health to improve patient participation in a definitive clinical trial.

Kidney involvement in Takayasu arteritis.

OBJECTIVE: To evaluate whether the presence of glomerulonephritis is or is not associated with the extent of arterial wall inflammatory cell infiltrate in Takayasu arthritis (TA). METHODS: Retrospective chart and pathology review of large artery and kidney specimens of TA autopsy cases. Kidney specimens were classified, according to their histopathological findings, in those with specific glomerular entities and those with non-specific, ischemic and/or hypertensive, glomerular changes. A control group of autopsy kidney specimens was utilized for comparison. Morphometric analysis was used to assess the extent of the arterial inflammatory infiltrates; results were compared among the different groups with kidney lesions. RESULTS: We included 25 kidney specimens from 25 autopsies. Specific glomerular entities were present in 14 specimens; 10 (40%) were classified as diffuse mesangial proliferative glomerulonephritis (DMPG [Group A]), and 4 (16%) as other associated glomerulopathies (Group B). Non-specific changes were observed in 11 (44%) specimens (Group C). The arterial inflammatory infiltrate proportion was 9.4 % for group A, 1.4% for group B, and 2.7% for group C. Furthermore, a larger proportion of vascular inflammation was confirmed for group A when compared with the other groups (p<0.05). Group A patients were younger than those in groups B and C (p<0.005) and exhibited shorter disease duration. CONCLUSION: The presence of DMPG was associated with a larger extent of vascular inflammatory cell infiltrate, suggesting a relationship between both phenomena.

Quantitative nanoscale electrostatics of viruses.

Electrostatics is one of the fundamental driving forces of the interaction between biomolecules in solution. In particular, the recognition events between viruses and host cells are dominated by both specific and non-specific interactions and the electric charge of viral particles determines the electrostatic force component of the latter. Here we probe the charge of individual viruses in liquid milieu by measuring the electrostatic force between a viral particle and the Atomic Force Microscope tip. The force spectroscopy data of co-adsorbed ϕ29 bacteriophage proheads and mature virions, adenovirus and minute virus of mice capsids is utilized for obtaining the corresponding density of charge for each virus. The systematic differences of the density of charge between the viral particles are consistent with the theoretical predictions obtained from X-ray structural data. Our results show that the density of charge is a distinguishing characteristic of each virus, depending crucially on the nature of the viral capsid and the presence/absence of the genetic material.

Interaction forces and conduction properties between multi wall carbon nanotube tips and Au(111).

We have studied the interaction forces and electrical conduction properties arising between multiwall carbon nanotube tips and the Au(111) surface in air, by means of amplitude modulation scanning force microscopy, also called intermittent contact. We have centered our work on tips with metallic electronic structure and for the specific parameters used we have found a preliminary interaction range where there is no contact between tip and surface. Stable imaging in this non-contact range is possible with multiwall carbon nanotube tips. These tips have also been used to obtain simultaneous topographic and current maps of the surface. They show excellent properties as tips due to their high aspect ratio and durability, as a result of their elastic and non-reactive properties. Correspondingly, multiwall carbon nanotube tips allow high resolution local analysis of electrical conductivity on a nanometer scale.

[Demographic study of tobacco addiction in Health District 5, Valencia, Spain]. / Estudio demográfico del tabaquismo en el Area de Salud 5 de Valencia.

OBJECTIVES: To determine the number of smokers, their demographic characteristics, and the stages of change among patients visiting health care centers. PATIENTS AND METHODS: Descriptive cross-sectional study carried out at 7 primary health care centers in Health District 5 of the Autonomous Community of Valencia. RESULTS: An interview was given to 3633 people with a mean (SD) age of 55 (19) years, (range: 14-96 years). Women made up 61.7%, and 65% were seeking medical attention. Twenty-three per cent were current smokers (mean age 41.8 [15.2] years), 17.2% ex-smokers (60.6 [16.2] years), and 59.8% never smokers (58.4 [18.8] years). The stages of change were pre-contemplation for 32.1%, contemplation for 4.9%, chronic contemplation for 12.2%, preparation to quit for 6.8%, action for 2.3%, maintenance for 15.1%, and termination for 26.7%. According to current recommendations, it seems that between 23.6% and 44.7%, depending on category definitions, needed specific attention concerning tobacco dependence. CONCLUSIONS: Twenty-three per cent of the patients attended by the primary care physician were smokers. More than half did not want to quit smoking and 1 in 10 were prepared to do so. Between 23.6% and 44.7% of the people who came to the primary care center needed specific attention concerning tobacco dependence.

[Nonbacterial thrombotic endocarditis as initial event of lung cancer]. / Endocarditis trombótica no bacteriana como manifestación inicial de neoplasia pulmonar.

Nonbacterial thrombotic endocarditis (NBTE) is a rare cause of peripheral embolism. NBTE is usually associated with malignant diseases and hypercoagulability states. Echocardiography is a very useful technique for the diagnosis. However valvular lesions in NBTE are similar to valvular vegetations observed from infectious endocarditis (IE), so it s necessary to establish a differential diagnosis. The treatment of thrombotic endocarditis is controversial, but the literature coincides in the use of intravenous heparin. We describe the case of a 42 years old woman with stroke in which transesophageal echocardiography (TEE) was useful in establishing the diagnosis of NBTE. The infectious origin was excluded with the realization of a exhaustive microbiologic study. In the search of causes for NBTE a lung adenocarcinoma was detected. In the present case the diagnosis of endocarditis preceded the neoplastic disease diagnosis.

[Pleurodesis with tetracycline in neoplastic effusions. Is an acid pH necessary?]. / Pleurodesis con tetraciclina en derrames neoplásicos. Es necesario un pH ácido?

Forty-three patients with recurrent malignant pleural effusions were included in a prospective protocol of treatment with two different types of tetracycline. Twenty-one patients (series A) were treated with a saline dilution of oxytetracycline (pH = 8) and twenty-two (series B) with a saline dilution of tetracycline chlorhydrate (pH = 2). Among the patients of series A, the rate of no recurrence of the effusion was 85.7% (12 out of 14 correctly treated and followed-up patients). In the series B, the rate of no recurrence was 86.6% (13 out of 15). The authors conclude that the pH of the tetracycline is not a determinant of pleural symphysis. The mechanism of action of the intrapleural tetracycline is discussed.