Background A series of human diseases are caused by the misfolding and aggregation of specific proteins or peptides into amyloid fibrils; nine of these diseases, referred to as polyglutamine diseases, are associated with proteins carrying an expanded polyglutamine (polyQ) region. While the presence of this latter is thought to be the determinant factor for the development of polyQ diseases, the non-polyQ regions of the host proteins are thought to play a significant modulating role. Method In order to better understand the role of non-polyQ regions, the toxic effects of model proteins bearing different polyQ regions (containing up to 79 residues) embedded at two distinct locations within the β-lactamase (BlaP) host enzyme were evaluated in Caenorhabditis elegans . This small organism can be advantageous for the validation of in vitro findings, as it provides a multicellular context yet avoids the typical complexity of common studies relying on vertebrate models. Several phenotypic assays were performed in order to screen for potential toxic effects of the different BlaP-polyQ proteins. Results Despite the significant in vitro aggregation of BlaP-polyQ proteins with long polyQ regions, none of the BlaP-polyQ chimeras aggregated in the generated transgenic in vivo models. Conclusion The absence of a toxic effect of the expression of BlaP-polyQ chimeras may find its cause in biochemical mechanisms present in vivo to cope with protein aggregation (e.g. presence of chaperones) or in C. elegans’ limitations such as its short lifespan. It is plausible that the aggregation propensities of the different BlaP chimeras containing embedded polyQ sequences are too low in this in vivo environment to permit their aggregation. These experiments emphasize the need for several comparative and in vivo verification studies of biologically relevant in vitro findings, which reveal both the strengths and limitations of widely used model systems.
Background Gold compounds have shown promise in the treatment of non-communicable diseases such as rheumatoid arthritis and cancer, and are considered of value as anti-microbial agents against Gram-negative and Gram-positive bacteria, and have anti-parasitic properties against Schistosoma mansoni , Trypanosoma brucei , Plasmodium falciparum , Leishmania infantinum , Giardia lamblia , and Entamoeba histolytica . They are known to affect enzymatic activities that are required for the cellular respiration processes. Methods Anti-amoebic effects of phosphanegold(I) thiolates were tested against clinical isolate of A. castellanii belonging to the T4 genotype by employing viability assays, growth inhibition assays, encystation assays, excystation assays, and zymographic assays. Results The treatment of A. castellanii with the phosphanegold(I) thiolates tested (i) had no effect on the viability of A. castellanii as determined by Trypan blue exclusion test, (ii) did not affect amoebae growth using PYG growth medium, (iii) did not inhibit cellular differentiation, and (iv) had no effect on the extracellular proteolytic activities of A. castellanii . Conclusion Being free-living amoeba, A. castellanii is a versatile respirator and possesses respiratory mechanisms that adapt to various aerobic and anaerobic environments to avoid toxic threats and adverse conditions. For the first time, our findings showed that A. castellanii exhibits resistance to the toxic effects of gold compounds and could prove to be an attractive model to study mechanisms of metal resistance in eukaryotic cells.
While the positive effect of balance training on age-related impairments in postural stability is well-documented, the neural correlates of such training adaptations in older adults remain poorly understood. This study therefore aimed to shed more light on neural adaptations in response to balance training in older adults.
Work-related stress is a global problem with negative implications for individuals and society. The purpose of the current study was to evaluate a stress management intervention for patients on sick leave due to work-related stress complaints using a three-armed randomized controlled design.
BACKGROUND:In vitro studies suggest that the multiple functions of decorin are related to both its core protein and its dermatan sulfate chain. To determine the contribution of the dermatan sulfate chain to the functional properties of decorin in vivo, a mutant mouse whose decorin lacked a dermatan sulfate chain was generated.RESULTS:Homozygous mice expressing only the decorin core protein developed and grew in a similar manner to wild type mice. In both embryonic and postnatal mice, all connective tissues studied, including cartilage, skin and cornea, appeared to be normal upon histological examination, and their collagen fibrils were of normal diameter and organization. In addition, abdominal skin wounds healed in an identical manner in the mutant and wild type mice.CONCLUSIONS:The absence of a dermatan sulfate chain on decorin does not appear to overtly influence its functional properties in vivo.
To investigate whether polymorphism rs540782 on chromsome 1, in close proximity to the Zona Pellucida Glycoprotein 4 (ZP4) gene, is a risk factor for primary open angle glaucoma (POAG).
Background The human leukemia cell line HL-60 is considered an alternative cell culture model to study neutrophil differentiation and migration. The aim of this study was to characterize the suitability of HL-60 cells differentiated to neutrophil-like cells (nHL-60) as substitute for blood-derived human neutrophils to investigate the interaction of neutrophils with Staphylococcus aureus . Methods For this purpose, antimicrobial activity, bacterial uptake, production of reactive oxygen species and the release of neutrophil extracellular traps (NETs) by nHL-60 cells were analyzed and compared to primary blood-derived neutrophils using Staphylococcus aureus as important human and animal pathogen. Results Overall, the antimicrobial activities of nHL-60 cells were distinctly lower compared to blood-derived neutrophils. Furthermore, production of reactive oxygen species as well as NET formation was clearly impaired in nHL-60 cells. Conclusion This study indicates that HL-60 cells are of limited usage as an alternative model to study antimicrobial functions of neutrophils against Staphylococcus aureus .
Background: Drug-induced parkinsonism (DIP) has a high prevalence and is associated with poorer quality of life. To find a practical clinical tool to assess DIP in patients with severe mental illness (SMI), the association between blink rate and drug-induced parkinsonism (DIP) was assessed.Methods: In a cohort of 204 SMI patients receiving care from the only mental health service of the previous Dutch Antilles, blink rate per minute during conversation was assessed by an additional trained movement disorder specialist. DIP was rated on the Unified Parkinson's Disease Rating Scale (UPDRS) in 878 assessments over a period of 18 years. Diagnostic values of blink rate were calculated.Results: DIP prevalence was 36%, average blink rate was 14 (standard deviation (SD) 11) for patients with DIP, and 19 (SD 14) for patients without. There was a significant association between blink rate and DIP (p < 0.001). With a blink rate cut-off of 20 blinks per minute, sensitivity was 77% and specificity was 38%. A 10% percentile cut-off model resulted in an area under the ROC curve of 0.61. A logistic prediction model between dichotomous DIP and continuous blink rate per minute an area under the ROC curve of 0.70.Conclusions: There is a significant association between blink rate and DIP as diagnosed on the UPDRS. However, blink rate sensitivity and specificity with regard to DIP are too low to replace clinical rating scales in routine psychiatric practice. Trial registration: The study was started over 20 years ago in 1992, at the time registering a trial was not common practice, therefore the study was never registered.
To investigate the association between polymorphism rs547984, located in close proximity to the Zona Pellucida Glycoprotein 4 (ZP4) gene on human chromosome 1q43 and primary open angle glaucoma (POAG).
We aimed to search for mutations in the germline and somatic DNA of the TEK gene and to analyze the expression level of Src and phospho-Src (p-Src) in tumor and healthy tissues from patients with facial cutaneo-mucosal venous malformations (VMCM). Eligible patients from twelve families and thirty healthy controls were recruited respectively at the Departments of Stomatology and Oral Surgery, and Transfusion Medicine of Tlemcen University Medical Centre. Immunoblot analyses of Src and p-Src were performed after direct DNA sequencing. No somatic or germline mutations were found in all the 23 exons and their 5' and 3' intronic flanking regions, except for one case in which a c.3025+20-3025+22 del mutation was highlighted at the intron 15, both in the germline and somatic DNA. Additionally, elevated expression levels of Src and p-Src were observed only in the patient with such mutation. However, when normalized to β-actin, the overall relative expression levels of both Src and p-Src were significantly increased in VMCM tissues when compared to healthy tissues (for both comparisons, p <0.001). In conclusion, we confirm the outcomes of our previous work suggesting that VMCM can develop independently of mutation of the TEK gene. Additionally, the results for Src activity are of particular interest in the context of specific targeted therapies and biological diagnosis. Nevertheless, such a conclusion should be confirmed through a mechanistic study and/or in a satisfactory number of patients.
BACKGROUND:Alzheimer disease (AD) research has focussed mainly on the amyloid beta protein (Aβ). However, many Aβ-and P3-type peptides derived from the amyloid precursor protein (APP) and peptides thought to derive from Aβ catabolism share sequence homology. Additionally, conformations can change dependent on aggregation state and solubility leading to significant uncertainty relating to interpretations of immunoreactivity with antibodies raised against Aβ. We review evidence relating to the reactivities of commonly used antibodies including 6F3D, 6E10 and 4G8 and evaluate their reactivity profiles with respect to AD diagnosis and research.RESULTS:Antibody cross-reactivities between Aβ-type, P3-type and Aβ-catabolic peptides confound interpretations of immunoreactivity. More than one antibody is required to adequately characterise Aβ. The relationships between anti-Aβ immunoreactivity, neuropathology and proposed APP cleavages are unclear.CONCLUSIONS:We find that the concept of Aβ lacks clarity as a specific entity. Anti-Aβ antibody cross-reactivities lead to significant uncertainty in our understanding of the APP proteolytic system and its role in AD with profound implications for current research and therapeutic strategies.
Objectives To investigate the effect of chronic lung inflammation on the incidence and severity of collagen-induced arthritis in mice. Methods Chronic lung inflammation in the form of silicosis was induced via intranasal application of silica particles. Immunization with collagen Type II commenced one week later and mice were sacrificed six weeks after booster immunization. Thereafter, silicosis was confirmed via flow cytometry and arthritis was evaluated performing knee and paw histology. Results Pronounced lung inflammation in the silica-treated compared to PBS-treated control mice was demonstrated by significantly elevated broncho-alveolar lavage (BAL) cell count, attributable to increased numbers of macrophages and granulocytes. Inflammation in the lungs was not associated with elevated PAD2 and PAD4 expression, yet silica treated animals had significantly higher aCCP serum titers. However, lung inflammation did not lead to an increase in the incidence of arthritis, nor did it exacerbate the macroscopic or histologic joint scores. Conclusions Chronic lung inflammation resulting from silicosis does not aggravate collagen-induced arthritis in mice.
Bronchoalveolar lavage (BAL) is a diagnostic tool often used during the management of interstitial lung diseases (ILD). However, its diagnostic value in discrimination between entities comprising the very heterogenous group of ILD, is still a controversial issue. The objective of our study is to assess the diagnostic value of BAL in the management of ILD, by comparing the cytological findings in BAL fluid among the different diseases of this group.
Medication effect is the sum of its drug, placebo, and drug*placebo interaction effects. It is conceivable that the interaction effect involves modulating drug bioavailability; it was previously observed that being aware of caffeine ingestion may prolong caffeine plasma half-life. This study was set to evaluate such concept using different drugs.
Background It has been suggested that mindfulness is a protective factor that buffers individuals from experiencing severe posttraumatic stress following exposure to a trauma. We aimed to examine the association between dispositional (trait) mindfulness and posttraumatic stress in individuals who had been exposed to the trauma of a natural disaster. Method A disaster group ( n = 25) consisting of Norwegian tourists who survived the 2004 South East Asian tsunami at a location with high mortality rates was recruited. Dispositional mindfulness and posttraumatic stress were measured with the Five-Facet Mindfulness Questionnaire and the Impact of Event Scale-Revised Version, respectively. Results There was no significant association between mindfulness and posttraumatic stress. Moreover, there were no significant associations between posttraumatic stress and the mindfulness sub-facets of observing, acting with awareness, non-judging, and non-reacting. However, there was a significant positive correlation between the descriptive factor of mindfulness and IES-R total. There were no significant linear correlations between the five sub-facets of mindfulness and the three categories of posttraumatic symptoms, intrusion, avoidance and hyper-arousal. Conclusions Our findings do not indicate a relationship between dispositional mindfulness and posttraumatic stress levels after exposure to a trauma, except for the descriptive sub-facet of mindfulness and here the correlation is positive and not negative as would be expected if mindfulness is a protective factor for posttraumatic stress. Future studies should investigate the relationship between mindfulness and posttraumatic stress while accounting for factors such as trauma history, type of trauma, and individual differences in traumatic stress reactions.
Mutations in the human progressive ankylosis gene (ANKH; Mus musculus ortholog Ank) have been identified as cause for craniometaphyseal dysplasia (CMD), characterized by progressive thickening of craniofacial bones and flared metaphyses of long bones. We previously reported a knock-in (KI) mouse model (Ank KI/KI) for CMD and showed transiently lower serum phosphate (Pi) as well as significantly higher mRNA levels of fibroblast growth factor 23 (Fgf23) in Ank KI/KI mice. FGF23 is secreted by bone and acts in kidney to promote Pi wasting which leads to lower serum Pi levels. Here, we examined whether increasing the Pi level can partially rescue the CMD-like skeletal phenotype by feeding Ank +/+ and Ank KI/KI mice with high Pi (1.7 %) diet from birth for 6 weeks. We studied the Pi metabolism in Ank KI/KI mice and CMD patients by examining the Pi regulators FGF23 and parathyroid hormone (PTH).
We investigated whether polymorphism rs7555523 (A > C) in human transmembrane and coiled-coil domain 1 (TMCO1) gene is a risk factor for primary open angle glaucoma (POAG) in a Saudi cohort.
A peer-reviewed journal would not survive without the generous time and insightful comments of the reviewers, whose efforts often go unrecognized. Although final decisions are always editorial, they are greatly facilitated by the deeper technical knowledge, scientific insights, understanding of social consequences, and passion that reviewers bring to our deliberations. For these reasons, the Editor-in-Chief, Managing Editor and staff of Journal of Negative Results in BioMedicine warmly thank the 51 reviewers whose comments helped to shape the journal, for their invaluable assistance with review of manuscripts in Volume 14 (2015).
BACKGROUND:Recently, topical dexamethasone-induced ocular hypertension and a consequent loss of retinal ganglion cells (RGCs) have been described in mice. This has been proposed as a model of steroid-induced glaucoma. In this study, we set up and evaluated a similar model in rats.RESULTS:Ten-week old Sprague Dawley (SD) rats (N = 12) were used to evaluate the effect of topical 0.1% dexamethasone (50 μl) administered 3 times daily for 4 weeks. Sodium chloride (0.9%) was used in another group of rats (N = 12) that served as the controls. After 1 week, we observed a progressive decrease in body weight in the dexamethasone-treated rats compared both to the pre-treatment baseline and the vehicle-treated rats. In contrast to earlier work that showed elevated Intraocular pressure (IOP) following dexamethasone instillation in mice, IOP in the rats unexpectedly fell to 11.3 ± 1.3 mmHg in the treated eyes, compared to 14.8 ± 2.4 mmHg in the untreated eyes, after 3 weeks of topical dexamethasone (P = 0.032). Blood tests performed after 4 weeks of treatment showed a 3.3-fold increase in both plasma cholesterol (P < 0.001) and alanine transaminase (P = 0.019) in the dexamethasone-treated rats compared to the control rats. Meanwhile, topical steroid did not induce changes in either plasma blood glucose or glycated hemoglobin (HbA1c). We also did not detect changes in the expression of RGC markers (with real-time PCR) following the treatment.CONCLUSIONS:In contrast to mice, which previously showed increased IOP following the topical administration of dexamethasone, the rats displayed a paradoxical reduction in IOP following a similar treatment. This was accompanied by a loss of body weight without affecting the level of blood glucose.
Toll-like receptors (TLRs) are involved in a variety of cardiovascular disorders, including septic cardiomyopathy, ischemia/reperfusion, heart failure, and cardiac hypertrophy. Previous research revealed that TLR4 promotes cardiac hypertrophy in vivo. Therefore, we investigated whether TLR2 is also involved in the development of cardiac hypertrophy.
