Emergence and evolution of the renin–angiotensin–aldosterone system

The renin-angiotensin-aldosterone system (RAAS) is not the sole, but perhaps the most important volume regulator in vertebrates. To gain insights into the function and evolution of its components, we conducted a phylogenetic analysis of its main related genes. We found that important parts of the system began to appear with primitive chordates and tunicates and that all major components were present at the divergence of bony fish, with the exception of the Mas receptor. The Mas receptor first appears after the bony-fish/tetrapod divergence. This phase of evolutionary innovation happened about 400 million years ago. We found solid evidence that angiotensinogen made its appearance in cartilage fish. The presence of several RAAS genes in organisms that lack all the components shows that these genes have had other ancestral functions outside of their current role. Our analysis underscores the utility of sequence comparisons in the study of evolution. Such analyses may provide new hypotheses as to how and why in today's population an increased activity of the RAAS frequently leads to faulty salt and volume regulation, hypertension, and cardiovascular diseases, opening up new and clinically important research areas for evolutionary medicine.     

Complexity and dynamics of host–fungal interactions

Pathologies attributable to fungal infections represent a growing concern in both developed and developing countries. Initially discovered as opportunistic pathogens of immunocompromised hosts, fungi such as Candida albicans are now being placed at the centre of a more complex and dynamic picture in which the outcome of an infection is the result of an intricate network of molecular interactions between the fungus, the host and the commensal microflora co-inhabiting various host niches, and especially the gastrointestinal (GI) tract. The complexity of the host-fungal interaction begins with the numerous pathogen-associated molecular patterns (PAMPs) present on the fungal cell wall that are recognized by multiple pathogen-recognition receptors (PRRs), expressed by several types of host cells. PAMP-PRR interactions elicit a variety of intracellular signalling pathways leading to a wide array of immune responses, some of which promote fungal clearance while others contribute to pathogenesis. The picture is further complicated by the fact that numerous commensal bacteria normally co-inhabiting the host's GI tract produce molecules that either directly modulate the survival and virulence of commensal fungi such as C. albicans or indirectly modulate the host's antifungal immune responses. On top of this complexity, this host-microbiome-fungal interaction exhibits features of a dynamic system, in which the same fungi can easily switch between different morphological forms presenting different PAMPs at different moments of time. Furthermore, fungal pathogens can rapidly accumulate genomic alterations that further modify their recognition by the immune system, their virulence and their resistance to antifungal compounds. Thus, based on available molecular data alone, it is currently difficult to construct a coherent model able to explain the balance between commensalism and virulence and to predict the outcome of a fungal infection. Here, we review current advances in our understanding of this complex and dynamic system and propose new avenues of investigation to assemble a more complete picture of the host-fungal interaction, integrating microbiological and immunological data under the lens of systems biology and evolutionary genomics.     

Inhibition of return in cue–target and target–target tasks

Inhibition of return (IOR), the term given for the slowing of a response to a target that appeared at the same location as a previously presented stimulus, has been studied with both target–target (TT; participants respond to each successive event) and cue–target (CT; participants only respond to the second of two events) tasks. Although both tasks have been used to examine the processes and characteristics of IOR, few studies have been conducted to understand if there are any differences in the processes that underlie the IOR that results from ignoring (CT paradigm) or responding to (TT paradigm) the first stimulus. The purpose of the present study was to examine the notion that IOR found in TT tasks represents “true” IOR whereas IOR found in CT tasks consist of both “true” IOR and response inhibition (Coward et al. in Exp Brain Res 155:124–128, 2004). Consistent with the pattern of effects found by Coward et al. (Exp Brain Res 155:124–128, 2004), IOR was larger in the CT task than in the TT task when a single detection response was required (Experiment 1). However, when participants completed one of two spatially-directed responses (rapid aiming movement to the location of the target stimulus), IOR effects from the CT and TT tasks were equal in magnitude (Experiment 2). Rather than CT tasks having an additional response inhibition component, these results suggest that TT tasks may show less of an inhibitory effect because of a facilitatory response repetition effect.     

Age and distress of women–results of a representative population-based study

Little research has been carried out on prevalence rates of distress (e.g. depression, posttraumatic stress symptoms (PTSS), hopelessness, and burnout) of women in different age groups. The aims of this study were to measure the prevalence rate of depression, posttraumatic stress symptoms, hopelessness, and burnout among women and to clarify the associations between age groups and distress. Cross sectional epidemiological study on women in Sweden (n = 6,000, aged 18–64 years, response rate 64.1%). Measures were questionnaires on socio-economic and work-related characteristics and on depression, posttraumatic stress symptoms, hopelessness, and burnout. Depression was measured with the “General Health Questionnaire” (GHQ), PTSS with the “Posttraumatic Symptom Scale”, hopelessness with the “Hopelessness Scale” and burnout with the “Shiron-Melamed Burnout Questionnaire” (SMBQ). The prevalence rate of depression varied from 12.5% to 14.1%; of posttraumatic stress symptoms from 23.5% to 33.3%; of hopelessness from 11.5% to 16%; and of burnout from 22.9% to 17.1%. Depression was not associated with age group. Hopelessness was associated with age group in univariate analysis bur not in multivariate analysis (OR = 0.7, 95% CI = 0.5–1.0). PTSS and burnout were associated with age group. Both symptoms were higher in the youngest age group, compared to the eldest age group (posttraumatic stress symptoms: OR = 1.6, 95% CI = 1.2, 2.1; burnout: OR = 1.5, 95% CI = 1.1–2.1). Younger women show higher prevalence rates of PTSS and burnout compared to elder women. The higher prevalence rates of PTSS and burnout among younger women may be associated with job strain and/or with violent life events.     

Pathogenesis and Immunobiology of Brucellosis: Review of Brucella–Host Interactions

This review of Brucella–host interactions and immunobiology discusses recent discoveries as the basis for pathogenesis-informed rationales to prevent or treat brucellosis. Brucella spp., as animal pathogens, cause human brucellosis, a zoonosis that results in worldwide economic losses, human morbidity, and poverty. Although Brucella spp. infect humans as an incidental host, 500,000 new human infections occur annually, and no patient-friendly treatments or approved human vaccines are reported. Brucellae display strong tissue tropism for lymphoreticular and reproductive systems with an intracellular lifestyle that limits exposure to innate and adaptive immune responses, sequesters the organism from the effects of antibiotics, and drives clinical disease manifestations and pathology. Stealthy brucellae exploit strategies to establish infection, including i) evasion of intracellular destruction by restricting fusion of type IV secretion system-dependent Brucella-containing vacuoles with lysosomal compartments, ii) inhibition of apoptosis of infected mononuclear cells, and iii) prevention of dendritic cell maturation, antigen presentation, and activation of naive T cells, pathogenesis lessons that may be informative for other intracellular pathogens. Data sets of next-generation sequences of Brucella and host time-series global expression fused with proteomics and metabolomics data from in vitro and in vivo experiments now inform interactive cellular pathways and gene regulatory networks enabling full-scale systems biology analysis. The newly identified effector proteins of Brucella may represent targets for improved, safer brucellosis vaccines and therapeutics.It is noteworthy that long ago in his publication Epidemics, Hippocrates described brucellosis-type syndromes in humans living in the Mediterranean littoral. Many centuries later, British physician, David Bruce, and Greek physician, Themistokles Zammit, in 1886 would discover the causative agent, Micrococcus melitensis, of brucellosis and would identify milk products of goats as the source of infection for military troops on the island of Malta. Even after more than a century of extensive research, Brucella spp. are still serious animal pathogens that cause brucellosis, a zoonosis that results in substantial economic losses, human morbidity, and perpetuates poverty worldwide.¹ These Gram-negative bacteria infect a diverse array of land and aquatic mammals, including swine, cattle, goat, sheep, dogs, dolphins, whales, seals, and desert wood rats. Traditionally, the genus Brucella consisted of six recognized species, grouped according to their primary host preferences, that is, B. abortus, cattle; B. melitensis, sheep and goats; B. suis, pigs; B. ovis, sheep; B. canis, dogs; and B. neotomae, wood desert rats. Recent isolates from human (B. inopinata), aquatic mammals (B. pinnipedialis and B. ceti), and a common vole (B. microti) are recognized as new species, bringing the current number to 10 species in the genus. The basis for host preference remains an open question, although there may be a role for pseudogenes that influence host adaptation. The global disease burden in livestock is enormous. Conservative estimates are that >300 million of the 1.4 billion worldwide cattle population is infected with the pathogen. Brucellosis in animals results in abortion and other disease manifestations.Brucella spp. infects humans as an incidental host. Human infection usually results from direct contact with tissues or blood from infected animals or by consumption of contaminated animal products, including unpasteurized milk and cheeses. In fact, >500,000 new human infections are estimated to occur annually. Brucellosis in humans typically presents with high, undulating fever. However, chronic brucellosis may affect many host organs, leading to arthritis, orchitis, hepatitis, encephalomyelitis, and endocarditis^2,3 (Figure 1). Arthritis represents the most common complication. The diverse manifestations of the disease complicate diagnosis. Brucellosis has eluded systematic attempts at eradication for more than a century, even in most developed countries, and no approved human vaccine is available. The low number of virulent organisms required for infection combined with the capacity for aerosolization renders Brucella spp. as category B pathogens and potential agents for bioterrorism. With an infectious dose of 10 to 100 organisms, the calculated financial risk of such an attack is second only to anthrax and tularemia. In addition, the threat of deliberate release poses a direct risk to public health in an urban population that cannot be mitigated through the normal approach of animal vaccination. Brucellosis in humans and livestock are relatively uncommon in industrialized nations because of routine screening of domestic livestock and animal vaccination. However, brucellosis is endemic in many developing regions of the globe, including the Middle East, Asia, Africa, and South America, and in the United States where foci of disease remain because of persistent infection in wildlife species. This review of Brucella–host interactions and Brucella immunobiology is intended to present recent pathogenetic discoveries as the basis for pathogenesis-informed rationales to prevent and treat brucellosis.Open in a separate windowFigure 1Hepatic and vertebral histopathology of human brucellosis caused by Brucella melitensis. A: Percutaneous liver biopsy. Mild nonspecific lymphocytic periportal hepatitis (arrow); stained with H&E. B: Percutaneous liver biopsy, culture positive for Brucella melitensis. Early-stage hepatic microgranuloma formation (arrow); stained with H&E. C: Guided needle core biopsy of vertebral body and epidural abscess, culture positive for Brucella melitensis. Lymphohistiocytic discitis osteomyelitis with dense cellular aggregates (arrow); stained with Diff-quik. Panels A and B are reproduced from Young et al² with permission from Elsevier. Panel C was provided by Drs. Supriya Narasimhan and Michael L. Deftos (Santa Clara Valley Medical Center, San Jose, CA). Original magnification, ×40. H&E, hematoxylin and eosin.     

Magnetic susceptibility and hardness of Au–xPt–yNb alloys for biomedical applications

Metal devices in the human body induce serious metal artifacts in magnetic resonance imaging (MRI). Metals artifacts are mainly caused by a volume magnetic susceptibility (χ_v) mismatch between a metal device and human tissue. In this research, Au–xPt–yNb alloys were developed for fabricating MRI artifact-free biomedical metal devices. The magnetic properties, hardness and phase constitutions of these alloys were investigated. The Au–xPt–8Nb alloys showed satisfactory χ_v values. Heat treatments did not clearly change the χ_v values for Au–xPt–8Nb alloys. The Vickers hardness (HV) of these two alloys was much higher than that of high-Pt alloys; moreover, aging at 700 °C increased the HV values of these two alloys. A dual phase structure consisting of face-centered cubic α1 and α2 phases was observed and aging at 700 °C promoted phase separation. The Au–5Pt–8Nb and Au–10Pt–8Nb alloys showed satisfactory χ_v values and high hardness and are thus suggested as candidates for MRI artifact-free alloys for biomedical applications.     

Influence of muscle architecture on the torque and power–velocity characteristics of young and elderly men

This study investigated the contribution of muscle architecture to the differences in the torque–velocity and power–velocity relationships between older (OM n = 9, aged 69–82 years) and younger men (YM n = 15, aged 19–35 years). Plantarflexors’ (PF) maximal isometric and concentric torques were recorded at 0.87, 1.75, 2.62, 3.49 and 4.36 rad s⁻¹. Physiological cross-sectional area (PCSA) was calculated as the ratio of muscle volume (determined by magnetic resonance imaging) to muscle fascicle length (L _f, measured by ultrasonography). GM PCSA and L _f of the OM were, respectively, 14.3% (P < 0.05) and 19.3% (P < 0.05) smaller than of the YM. In the OM, GM maximum isometric torque and maximum contraction velocity (V _max), estimated from Hill’s equation were, respectively, 48.5 and 38.2% lower (P < 0.001) than in the YM. At all contraction velocities, the OM produced less torque than the YM (46.3% of YM at 0.87 rad s⁻¹ to 14.7% at 4.36 rad s⁻¹, P < 0.001). Peak power (PP) of the OM was 80% lower than that of the YM and normalisation of PP to muscle volume only reduced this difference by 10%. Normalisation of torque to PCSA reduced, but did not eliminate, differences in torque between YM and OM (9.6%) and differences in torque/PCSA increased with contraction velocity (P < 0.05). After normalisation of velocity to L _f, the difference in V _max between the OM and the YM was reduced to 15.9%. Thus, although muscle architecture contributes significantly to the differences in the torque– and power–velocity properties of OM and YM, other contractile factors, intrinsic to the muscle, seem to play a role. It is noteworthy that the deficit in PP between OM and YM is far greater than that of muscle torque, even after normalisation of PP to muscle volume. This finding likely plays an important role in the loss of mobility in old age.     

Correlates of child–father and child–mother attachment in the preschool years

The increase in fathers’ involvement in childrearing, particularly beyond infancy, warrants research exploring factors influencing the quality of child–father attachment relationships, and the impact of these relationships on children’s social development. The current investigation explored various correlates of preschoolers’ child–father attachment security to both parents, including contextual factors (i.e., socioeconomic status, child temperament, parenting stress), parental play sensitivity, and child social adaptation. Participants included 107 preschool-aged children (59 girls; M = 46.67 months, SD = 8.57) and their fathers and mothers. Results revealed that both mothers’ and fathers’ play sensitivity were associated with child attachment security after controlling for different contextual factors. Furthermore, the magnitude of the association between child conduct problems and child–father attachment insecurity was stronger than the corresponding association with child–mother attachment insecurity. Findings provide important information on caregiving factors associated with child–father attachment security in the preschool years and the importance of this bond to children’s social adaptation.     

Usefulness of Negative and Weak–Diffuse Pattern of SDHB Immunostaining in Assessment of SDH Mutations in Paragangliomas and Pheochromocytomas

This is a confirmatory study about usefulness of SDHB and SDHA immunostaining in assessment of SDH mutations in paragangliomas and pheochromocytomas. Paraganglioma/pheochromocytoma syndrome (PGL/PCC syndrome) consists of different entities, associated with germline mutations in five different genes: SDHD, SDHAF2, SDHC, SDHA and SDHB. It has been suggested that negative immunostaining of SDHB can be taken as an indicator of the presence of a mutation in one of the five SDH genes. We have performed SDHB and SDHA immunohistochemical staining in a series of paragangliomas and pheochromocytomas from 64 patients. The patients had been previously checked for mutations in SDHD, SDHC and SDHB, but also for mutation in RET and VHL. All 14 patients with SDH mutations (9 with SDHB and 5 with SDHD mutations) exhibited negative or weak–diffuse SDHB staining pattern in tumour tissue, whereas cells of the 23 RET mutated and 8 VHL mutated tumours showed a positive SDHB immunostaining. Sixteen of the patients that did not exhibit a mutation in any gene showed positive SDHB immunostaining in tumour tissue, while only three of the patients without mutation exhibited negative staining. All patients exhibited positive pattern of SDHA immunostaining. The results confirm the value of SDHB immunohistochemical status in assessment of germline mutations in PGL/PCC syndrome.     

DeFries–Fulker and Pearson–Aitken Model-fitting Analyses of Reading Performance Data from Selected and Unselected Twin Pairs

Although a comparison of concordance rates for deviant scores in identical and fraternal twin pairs can provide prima facie evidence for a genetic etiology, information is not fully utilized when continuous measures are analyzed in a dichotomous manner. Thus, DeFries and Fulker (Behav Genet 15:467–473, 1985; Acta Genet Med Gemellol, 37:205–216, 1988) developed a regression-based methodology (DF analysis) to assess genetic etiology in both selected and unselected twin samples. While the DF analysis is a very versatile and relatively powerful statistical approach, it is not easily extended to the multivariate case. In contrast, structural equation models may be readily extended to analyze multivariate data sets (Neale and Cardon, Methodology for genetic studies of twins and families, 1992). However, such methodologies may yield biased estimates of additive genetic, shared environmental, and non-shared environmental influences when multivariate models are fitted to selected twin data. Therefore, the Pearson–Aitken (PA) selection formula (Aitken, Proc Edinburgh Math Soc B, 4:106–110, 1934) was used to analyze reading performance data from twins with reading difficulties (selected sample) and a population of normally-achieving twin pairs (control sample). As a comparison, DF models were also fitted to these same data sets. In general, resulting estimates of additive genetic, shared environmental, and non-shared environmental influences were similar when the DF and PA models were fitted to the data. However, the PA selection formula may be more readily generalized to the multivariate case. Edited by Hermine Maes.     

Clinical and molecular pathology of the metaplasia–dysplasia–carcinoma sequence in Barrett's oesophagus

Recent research has led to a much greater understanding of the molecular mechanisms driving the neoplastic progression of Barrett's oesophagus (columnar-lined oesophagus, CLO) metaplasia through grades of dysplasia to adenocarcinoma, with the promise of future novel diagnostic techniques and therapies to help counter the striking increased incidence and mortality reported for CLO-related cancer in the West. Key genetic changes include telomerase re-activation, loss of p53 expression (by mutation or deletion) loss of p16 gene expression (by mutation or hypermethylation), increased cyclin D1 expression and aneuploidy.However, until relevant and reliable molecular diagnostic aids come into routine diagnostic practice, the onus on accurate disease monitoring remains based on morphology, highlighting the need for accurate and reproducible criteria for the histopathological diagnosis of pre-malignant and malignant mucosal changes in the metaplasia–dysplasia–carcinoma sequence of CLO.     

Effects of In Situ and Physical Mixing on Mechanical and Bioactive Behaviors of Nano Hydroxyapatite–Chitosan Scaffolds

Nano hydroxyapatite (HAP) was employed to intensify chitosan (CS) scaffolds by two methods. The first one is nano HAP crystallized in situ from the CS matrix by a biomimetic method (in situ scaffold). In the second method the sol–gel nano HAP powder was added directly to the CS solution (physical mixing scaffold). The distribution status of nano HAP was examined by scanning electron microscopy. The compressive performance was measured by a universal material testing machine. The in vitro study in stimulated body fluid was performed to evaluate the biological properties of both scaffolds. MTT testing and alkaline phosphatase activity from human bone mesenchymal stem cell culture showed differences in biocompatibility and bioactivity between the scaffolds. The results indicated that the in situ scaffold possessed more excellent mechanical and bioactive behaviors than that of the physical mixing scaffold.     

Functional capacities of Polish adults of 60–87 years and risk of losing functional independence

Aim: To characterise the functional capacities of Polish men and women aged 60–87?years and evaluate their status relative to criteria for functional independence.

Subjects and methods: Four hundred and thirty-one women and 125 men, aged 60–87?years, who were residents of Wroc?aw, southwestern Poland, were recruited. Height and weight were measured and BMI was calculated. The Fullerton Functional Fitness Test was administered to test upper and lower body strength, upper and lower body flexibility, agility-dynamic balance and aerobic endurance. The Paffenbarger physical activity questionnaire was completed. Characteristics of individuals classified by the number of tests which equalled or exceeded criterion-referenced standards for functional independence (excluding flexibility) were compared.

Results: Polish older adults compared favourably to American reference values. Percentages meeting the criteria for all four, for two or three and for one or no tests were, respectively, 21%, 54% and 25% in women and 37%, 45% and 18% in men. Adults meeting the criteria for all four tests were lighter, with a lower BMI and more physically active than those meeting the criteria on two or three tests and on one or no tests.

Conclusion: The majority of Polish older adults were not at risk for loss of physical independence. The most functionally independent adults of both sexes had a lower BMI and less obesity, and were physically more active; the converse was true for those not meeting the criteria.     

A Surface–Regional and Freeze–Thaw Characterization of the Porcine Temporomandibular Joint Disc

The temporomandibular joint (TMJ) disc is a central element in several TMJ disorders. Tissue-engineered TMJ disc replacements may alleviate discomfort associated with TMJ disorders; however, prior to developing a replacement, a thorough understanding of the native disc must be attained. Toward this end, we developed an unconfined compression, incremental stress relaxation viscoelastic model which simultaneously incorporates the strain increment magnitude and total deformation in the stress relaxation solution. This multiple strain step model was fit to stress relaxation data from (i) 80 test sites from eight porcine TMJ discs for the purposes of a surface–regional characterization and (ii) 30 test sites from five porcine TMJ discs for the purposes of a freeze–thaw characterization. The model estimated viscoelastic parameters accurately and surface–regional variations were detected throughout the TMJ disc. Regionally, the medial and anterior regions have the largest relaxation moduli, and the posterior and anterior regions have the largest instantaneous moduli. The inferior surface was found to have higher instantaneous modulus values than the superior surface. Furthermore, material properties were retained over five freeze–thaw cycles. The results of this study allow for the creation of design and validation criteria for future engineering efforts and shed light on the disc’s role in TMJ function and dysfunction.     

In vitro and in vivo corrosion,cytocompatibility and mechanical properties of biodegradable Mg–Y–Ca–Zr alloys as implant materials

This study introduces a class of biodegradable Mg–Y–Ca–Zr alloys novel to biological applications and presents evaluations for orthopedic and craniofacial implant applications. Mg–Y–Ca–Zr alloys were processed using conventional melting and casting techniques. The effects of increasing Y content from 1 to 4 wt.% as well as the effects of T4 solution treatment were assessed. Basic material phase characterization was conducted using X-ray diffraction, optical microscopy and scanning electron microscopy. Compressive and tensile tests allowed for the comparison of mechanical properties of the as-cast and T4-treated Mg–Y–Ca–Zr alloys to pure Mg and as-drawn AZ31. Potentiodynamic polarization tests and mass loss immersion tests were used to evaluate the corrosion behavior of the alloys. In vitro cytocompatibility tests on MC3T3-E1 pre-osteoblast cells were also conducted. Finally, alloy pellets were implanted into murine subcutaneous tissue to observe in vivo corrosion as well as local host response through H&E staining. SEM/EDS analysis showed that secondary phase intermetallics rich in yttrium were observed along the grain boundaries, with the T4 solution treatment diffusing the secondary phases into the matrix while increasing the grain size. The alloys demonstrated marked improvement in mechanical properties over pure Mg. Increasing the Y content contributed to improved corrosion resistance, while solution-treated alloys resulted in lower strength and compressive strain compared to as-cast alloys. The Mg–Y–Ca–Zr alloys demonstrated excellent in vitro cytocompatibility and normal in vivo host response. The mechanical, corrosion and biological evaluations performed in this study demonstrated that Mg–Y–Ca–Zr alloys, especially with the 4 wt.% Y content, would perform well as orthopedic and craniofacial implant biomaterials.     

Effect of preparation conditions on properties and permeability of chitosan–sodium hexametaphosphate capsules

Capsules were obtained by interpolymer complexation between chitosan (polycation) and sodium hexametaphosphate (SMP, oligoanion). The effect of the preparation conditions on the capsule characteristics was evaluated. Specifically, the influence of variables such as pH, ionic strength, reagent concentration, and additives on the capsule permeability properties was investigated using dextran as a model permeant. The capsule membrane permeability was found to increase by decreasing the chitosan/SMP ratio as well as adding mannitol to the oligoanion recipient bath. Increasing the ionic strength or the pH of the initial chitosan solution was also found to enhance the membrane permeability, moving the membrane exclusion limit to higher values. Generally, the capsules prepared under all tested conditions had a relatively low permeability which rarely exceeded a molecular cut-off of 40 kD based on dextran standards. Furthermore, the diffusion rate showed a strong temporal dependence, indicating that the capsules prepared under various conditions exhibit different apparent pore size densities on the surface. The results indicated that, in order to obtain the desired capsule mass-transfer properties, the preparation conditions should be carefully considered and adjusted. Adding a polyol as well as low salt amount (less than 0.15%) is preferable as a means of modulating the diffusion characteristics, without disturbing the capsule mechanical stability.