Your browser doesn't support javascript.
loading
Show: 20 | 50 | 100
Results 1 - 12 de 12
Filter
Add more filters











Publication year range
1.
Global Spine J ; : 21925682241290226, 2024 Oct 10.
Article in English | MEDLINE | ID: mdl-39387468

ABSTRACT

Spine disorders are the leading cause of disability worldwide. To promote social inclusion, it is essential to ensure that people can participate in their societies by improving their ability, opportunities, and dignity, through access to high-quality, evidence-based, and affordable spine services for all.To achieve this goal, SPINE20 recommends six actions.- SPINE20 recommends that G20 countries deliver evidence-based education to the community health workers and primary care clinicians to promote best practice for spine health, especially in underserved communities.- SPINE20 recommends that G20 countries deliver evidence-based, high-quality, cost-effective spine care interventions that are accessible, affordable and beneficial to patients.- SPINE20 recommends that G20 countries invest in Health Policy and System Research (HPSR) to generate evidence to develop and implement policies aimed at integrating rehabilitation in primary care to improve spine health.- SPINE20 recommends that G20 countries support ongoing research initiatives on digital technologies including artificial intelligence, regulate digital technologies, and promote evidence-based, ethical digital solutions in all aspects of spine care, to enrich patient care with high value and quality.- SPINE20 recommends that G20 countries prioritize social inclusion by promoting equitable access to comprehensive spine care through collaborations with healthcare providers, policymakers, and community organizations.- SPINE20 recommends that G20 countries prioritize spine health to improve the well-being and productivity of their populations. Government health systems are expected to create a healthier, more productive, and equitable society for all through collaborative efforts and sustained investment in evidence-based care and promotion of spine health.

2.
Int J Parasitol Drugs Drug Resist ; 23: 120-129, 2023 Dec.
Article in English | MEDLINE | ID: mdl-38043188

ABSTRACT

Toxoplasma gondii is an obligate intracellular parasite in the phylum Apicomplexa that causes toxoplasmosis in humans and animals worldwide. Despite its prevalence, there is currently no effective vaccine or treatment for chronic infection. Although there are therapies against the acute stage, prolonged use is toxic and poorly tolerated. This study aims to explore the potential of repurposing topotecan and 10-hydroxycamptothecin (HCPT) as drugs producing double strand breaks (DSBs) in T. gondii. DSBs are mainly repaired by Homologous Recombination Repair (HRR) and Non-Homologous End Joining (NHEJ). Two T. gondii strains, RHΔHXGPRT and RHΔKU80, were used to compare the drug's effects on parasites. RHΔHXGPRT parasites may use both HRR and NHEJ pathways but RHΔKU80 lacks the KU80 protein needed for NHEJ, leaving only the HRR pathway. Here we demonstrate that topotecan and HCPT, both topoisomerase I venoms, affected parasite replication in a concentration-dependent manner. Moreover, variations in fluorescence intensity measurements for the H2A.X phosphorylation mark (γH2A.X), an indicator of DNA damage, were observed in intracellular parasites under drug treatment conditions. Interestingly, intracellular replicative parasites without drug treatment show a strong positive staining for γH2A.X, suggesting inherent DNA damage. Extracellular (non-replicating) parasites did not exhibit γH2A.X staining, indicating that the basal level of DNA damage is likely to be associated with replicative stress. A high rate of DNA replication stress possibly prompted the evolution of an efficient repair machinery in the parasite, making it an attractive target. Our findings show that topoisomerase 1 venoms are effective antiparasitics blocking T. gondii replication.


Subject(s)
Parasites , Toxoplasma , Humans , Animals , Toxoplasma/genetics , Topotecan/pharmacology , Topotecan/metabolism , DNA Repair , DNA Damage
3.
bioRxiv ; 2023 Feb 24.
Article in English | MEDLINE | ID: mdl-36824796

ABSTRACT

Through regulation of DNA packaging, histone proteins are fundamental to a wide array of biological processes. A variety of post-translational modifications (PTMs), including acetylation, constitute a proposed histone code that is interpreted by "reader" proteins to modulate chromatin structure. Canonical histones can be replaced with variant versions that add an additional layer of regulatory complexity. The protozoan parasite Toxoplasma gondii is unique among eukaryotes in possessing a novel variant of H2B designated H2B.Z. The combination of PTMs and the use of histone variants is important for gene regulation in T. gondii, offering new targets for drug development. In this work, T. gondii parasites were generated in which the 5 N-terminal acetylatable lysines in H2B.Z were mutated to either alanine (c-Myc-A) or arginine (c-Myc-R). c-Myc-A mutant only displayed a mild effect in its ability to kill mice. c-Myc-R mutant presented an impaired ability to grow and an increase in differentiation to latent bradyzoites. This mutant line was also more sensitive to DNA damage, displayed no virulence in mice, and provided protective immunity against future infection. While nucleosome composition was unaltered, key genes were abnormally expressed during in vitro bradyzoite differentiation. Our results show that the N-terminal positive charge patch of H2B.Z is important for these procceses. Pull down assays with acetylated N-terminal H2B.Z peptide and unacetylated one retrieved common and differential interactors. Acetylated peptide pulled down proteins associated with chromosome maintenance/segregation and cell cycle, opening the question of a possible link between H2B.Z acetylation status and mitosis.

4.
Article in English | MEDLINE | ID: mdl-32656097

ABSTRACT

Toxoplasma gondii is the causative agent of toxoplasmosis in animals and humans. This infection is transmitted to humans through oocysts released in the feces of the felines into the environment or by ingestion of undercooked meat. This implies that toxoplasmosis is a zoonotic disease and T. gondii is a foodborne pathogen. In addition, chronic toxoplasmosis in goats and sheep is the cause of recurrent abortions with economic losses in the sector. It is also a health problem in pets such as cats and dogs. Although there are therapies against this infection in its acute stage, they are not able to permanently eliminate the parasite and sometimes they are not well tolerated. To develop better, safer drugs, we need to elucidate key aspects of the biology of T. gondii. In this review, we will discuss the importance of the homologous recombination repair (HRR) pathway in the parasite's lytic cycle and how components of these processes can be potential molecular targets for new drug development programs. In that sense, the effect of different DNA damage agents or HHR inhibitors on the growth and replication of T. gondii will be described. Multitarget drugs that were either associated with other targets or were part of general screenings are included in the list, providing a thorough revision of the drugs that can be tested in other scenarios.


Subject(s)
Pharmaceutical Preparations , Toxoplasma , Toxoplasmosis, Animal , Animals , Cats , DNA Damage , DNA Repair , Dogs , Sheep , Toxoplasma/genetics , Toxoplasmosis, Animal/drug therapy
5.
PM R ; 12(10): 957-966, 2020 10.
Article in English | MEDLINE | ID: mdl-32248638

ABSTRACT

BACKGROUND: Lower-limb amputation (LLA) due to non-traumatic vascular etiology is linked to extremely low physical activity and high disability. OBJECTIVE: To test the feasibility of a biobehavioral intervention designed to promote physical activity. DESIGN: A randomized, single-blind feasibility trial with a crossover design. SETTING: Veterans Administration Medical Center. PARTICIPANTS: Military veterans (age: 65.7 [7.8] years; mean [standard deviation]) with nontraumatic lower-limb amputation (LLA), randomized to two groups: GROUP1 (n = 16) and GROUP2 (n = 15). Both groups had similar baseline amputation characteristics (level of amputation and time since amputation). INTERVENTIONS: Twelve weekly, 30-minute telehealth sessions of physical activity behavior-change intervention, with GROUP1 participating in weeks 1-12 and GROUP2 in weeks 13-24. GROUP1 noncontact phase in weeks 13-24 and GROUP2 attention control telehealth phase in weeks 1-12. MAIN OUTCOME MEASURES: Feasibility (participant retention, dose goal attainment, intervention acceptability [Intrinsic Motivation Inventory [IMI] Interest and Enjoyment scale], safety) and signal of efficacy (free-living physical activity [accelerometer-based average daily step count], Late Life Function and Disability Index - Disability Scale [LLFDI-DS]). RESULTS: Participant retention rate was high (90%), with three participants lost to follow-up during the intervention period. Dose goal attainment was low, with only 10% of participants achieving an a priori walking dose goal. Intervention was rated as acceptable, with mean IMI Interest and Enjoyment score (5.8) statistically higher than the null value of 5.0 (P = .002). There were no between-group differences in adverse event rates (falls: P = .19, lower extremity wounds: P = .60). There was no signal of efficacy for change in average daily step count (d = -0.15) or LLFDI-DS (d = -0.22 and 0.17 for frequency and limitations scales, respectively). CONCLUSIONS: Telehealth delivered biobehavioral intervention resulted in acceptable participant retention, low dose goal attainment, high participant acceptability, and low safety risk, while having no signal of efficacy (physical activity, disability) for people with nontraumatic LLA.


Subject(s)
Veterans , Aged , Amputation, Surgical , Exercise , Humans , Male , Single-Blind Method , Walking
6.
Article in English | MEDLINE | ID: mdl-30815397

ABSTRACT

Toxoplasma gondii is an apicomplexan protozoan parasite with a complex life cycle composed of multiple stages that infect mammals and birds. Tachyzoites rapidly replicate within host cells to produce acute infection during which the parasite disseminates to tissues and organs. Highly replicative cells are subject to Double Strand Breaks (DSBs) by replication fork collapse and ATM, a member of the phosphatidylinositol 3-kinase (PI3K) family, is a key factor that initiates DNA repair and activates cell cycle checkpoints. Here we demonstrate that the treatment of intracellular tachyzoites with the PI3K inhibitor caffeine or ATM kinase-inhibitor KU-55933 affects parasite replication rate in a dose-dependent manner. KU-55933 affects intracellular tachyzoite growth and induces G1-phase arrest. Addition of KU-55933 to extracellular tachyzoites also leads to a significant reduction of tachyzoite replication upon infection of host cells. ATM kinase phosphorylates H2A.X (γH2AX) to promote DSB damage repair. The level of γH2AX increases in tachyzoites treated with camptothecin (CPT), a drug that generates fork collapse, but this increase was not observed when co-administered with KU-55933. These findings support that KU-55933 is affecting the Toxoplasma ATM-like kinase (TgATM). The combination of KU-55933 and other DNA damaging agents such as methyl methane sulfonate (MMS) and CPT produce a synergic effect, suggesting that TgATM kinase inhibition sensitizes the parasite to damaged DNA. By contrast, hydroxyurea (HU) did not further inhibit tachyzoite replication when combined with KU-55933.


Subject(s)
Antiprotozoal Agents/pharmacology , Morpholines/pharmacology , Protein Kinase Inhibitors/pharmacology , Pyrones/pharmacology , Toxoplasma/drug effects , Toxoplasma/growth & development , Drug Synergism
7.
PM R ; 10(5): 544-547, 2018 05.
Article in English | MEDLINE | ID: mdl-29074369

ABSTRACT

A 30-year-old man with no significant medical history presented with hypokalemic quadriplegia 4 hours after he received a lumbar transforaminal epidural steroid injection (ESI) containing dexamethasone and lidocaine. A comprehensive workup ruled out acquired and hereditary causes of hypokalemic paralysis. Symptoms gradually resolved within hours after potassium restoration with no residual neurologic deficits. Paralysis after transforaminal ESI is uncommon but has been associated with particulate steroids that can coalesce into aggregates and occlude vessels. To our knowledge, there have been no case reports of paralysis after ESI with dexamethasone, a nonparticulate steroid. This transient paralysis is possibly caused by the effects of glucocorticoids on Na-K channels and insulin resistance resulting in hyperglycemia and subsequent hypokalemia. We reviewed the differential diagnosis of transient paralysis after epidural steroid injection in this report. LEVEL OF EVIDENCE: IV.


Subject(s)
Dexamethasone/adverse effects , Hypokalemia/chemically induced , Low Back Pain/drug therapy , Quadriplegia/chemically induced , Adult , Dexamethasone/administration & dosage , Fluoroscopy , Follow-Up Studies , Glucocorticoids/administration & dosage , Glucocorticoids/adverse effects , Humans , Hypokalemia/complications , Injections, Epidural/adverse effects , Low Back Pain/diagnosis , Lumbar Vertebrae , Male , Quadriplegia/etiology
8.
Mol Biochem Parasitol ; 197(1-2): 36-42, 2014 Oct.
Article in English | MEDLINE | ID: mdl-25286383

ABSTRACT

Histone H2Ba of Toxoplasma gondii was expressed as recombinant protein (rH2Ba) and used to generate antibody in mouse that is highly specific. Antibody recognizing rH2Ba detects a single band in tachyzoite lysate of the expected molecular weight (12kDa). By indirect immunofluorescence (IFA) in in vitro grown tachyzoites and bradyzoites, the signal was detected only in the parasite nucleus. The nucleosome composition of H2Ba was determined through co-immunoprecipitation assays. H2Ba was detected in the same immunocomplex as H2A.X, but not with H2A.Z. Through chromatin immunoprecipitation (ChIP) assays and qPCR, it was observed that H2Ba is preferentially located at promoters of inactive genes and silent regions, accompanying H2A.X and opposed to H2A.Z/H2B.Z dimers.


Subject(s)
Genome, Protozoan , Histones/genetics , Toxoplasma/genetics , Antibodies, Monoclonal/immunology , Chromatin Immunoprecipitation , Histones/chemistry , Histones/immunology , Histones/metabolism , Models, Biological , Nucleosomes/metabolism , Protein Multimerization , Protein Transport , Recombinant Proteins/chemistry , Recombinant Proteins/genetics , Recombinant Proteins/immunology , Recombinant Proteins/metabolism
9.
Expert Rev Anti Infect Ther ; 10(10): 1189-201, 2012 Oct.
Article in English | MEDLINE | ID: mdl-23199404

ABSTRACT

Toxoplasma gondii is a leading cause of neurological birth defects and a serious opportunistic pathogen. The authors and others have found that Toxoplasma uses a unique nucleosome composition supporting a fine gene regulation together with other factors. Post-translational modifications in histones facilitate the establishment of a global chromatin environment and orchestrate DNA-related biological processes. Histone acetylation is one of the most prominent post-translational modifications influencing gene expression. Histone acetyltransferases and histone deacetylases have been intensively studied as potential drug targets. In particular, histone deacetylase inhibitors have activity against apicomplexan parasites, underscoring their potential as a new class of antiparasitic compounds. In this review, we summarize what is known about Toxoplasma histone acetyltransferases and histone deacetylases, and discuss the inhibitors studied to date. Finally, the authors discuss the distinct possibility that the unique nucleosome composition of Toxoplasma, which harbors a nonconserved H2Bv variant histone, might be targeted in novel therapeutics directed against this parasite.


Subject(s)
Histones/metabolism , Toxoplasma/genetics , Toxoplasmosis/drug therapy , Acetylation , Amino Acid Sequence , Antiparasitic Agents/therapeutic use , Chromatin/metabolism , Histone Acetyltransferases/genetics , Histone Acetyltransferases/metabolism , Histone Deacetylase Inhibitors/therapeutic use , Histone Deacetylases/genetics , Histone Deacetylases/metabolism , Histones/chemistry , Humans , Molecular Sequence Data , Nucleosomes/metabolism , Protein Processing, Post-Translational , Sequence Alignment , Toxoplasmosis/genetics
10.
Int J Biol Macromol ; 50(3): 725-33, 2012 Apr 01.
Article in English | MEDLINE | ID: mdl-22209934

ABSTRACT

Toxoplasma gondii is an obligate intracellular protozoan parasite in which 36 predicted Hsp40 family members were identified by searching the T. gondii genome. The predicted protein sequence from the gene ID TGME49_065310 showed an amino acid sequence and domain structure similar to Saccharomyces cerevisiae Sis1. TgSis1 did not show differences in its expression profile during alkaline stress by microarray analysis. Furthermore, TgSis1 showed to be a cytosolic Hsp40 which co-immunoprecipitated with T. gondii Hsp70 and Hsp90. Structural modeling of the TgSis1 peptide binding fragment revealed structural and electrostatic properties different from the experimental model of human Sis1-like protein (Hdj1). Based on these differences; we propose that TgSis1 may be a potentially attractive drug target for developing a novel anti-T. gondii therapy.


Subject(s)
Cytosol/metabolism , HSP40 Heat-Shock Proteins/metabolism , HSP70 Heat-Shock Proteins/metabolism , HSP90 Heat-Shock Proteins/metabolism , Protozoan Proteins/metabolism , Toxoplasma/cytology , Toxoplasma/metabolism , Amino Acid Sequence , Databases, Genetic , HSP40 Heat-Shock Proteins/chemistry , HSP40 Heat-Shock Proteins/genetics , Humans , Intracellular Space/metabolism , Models, Molecular , Molecular Sequence Data , Protein Conformation , Protein Structure, Tertiary , Protein Transport , Protozoan Proteins/chemistry , Protozoan Proteins/genetics , Sequence Analysis , Stress, Physiological , Toxoplasma/genetics
11.
J Mol Biol ; 392(1): 33-47, 2009 Sep 11.
Article in English | MEDLINE | ID: mdl-19607843

ABSTRACT

Toxoplasma gondii is an obligate intracellular parasite. Toxoplasmosis is incurable because of its ability to differentiate from the rapidly replicating tachyzoite stage into a latent cyst form (bradyzoite stage). Gene regulation pertinent to Toxoplasma differentiation involves histone modification, but very little is known about the histone proteins in this early branching eukaryote. Here, we report the characterization of three H2A histones, variants H2AX and H2AZ, and a canonical H2A1. H2AZ is the minor parasite H2A member. H2A1 and H2AX both have an SQ motif, but only H2AX has a complete SQ(E/D)varphi (where varphi denotes a hydrophobic residue) known to be phosphorylated in response to DNA damage. We show that a novel H2B variant interacts with H2AZ and H2A1 but not with H2AX. Chromatin immunoprecipitation (ChIP) revealed that H2AZ and H2Bv are enriched at active genes while H2AX is enriched at repressed genes as well as the silent TgIRE repeat element. During DNA damage, we detected an increase in H2AX phosphorylation as well as increases in h2a1 and h2ax transcription. We found that expression of h2ax, but not h2a1 or h2az, increases in bradyzoites generated in vitro. Similar analysis performed on mature bradyzoites generated in vivo, which are arrested in G0, showed that h2az and h2ax are expressed but h2a1 is not, consistent with the idea that h2a1 is the canonical histone orthologue in the parasite. The increase of H2AX, which localizes to silenced areas during bradyzoite differentiation, is consistent with the quiescent nature of this stage of the life cycle. Our results indicate that the early-branching eukaryotic parasite Toxoplasma contains nucleosomes of novel composition, which is likely to impact multiple facets of parasite biology, including the clinically important process of bradyzoite differentiation.


Subject(s)
Gene Expression Regulation , Histones/metabolism , Nucleosomes/chemistry , Nucleosomes/metabolism , Protozoan Proteins/metabolism , Toxoplasma/physiology , Amino Acid Sequence , Animals , Chromatin Immunoprecipitation/methods , DNA, Protozoan/metabolism , Histones/genetics , Molecular Sequence Data , Mutant Proteins/genetics , Mutant Proteins/metabolism , Protein Binding , Protozoan Proteins/genetics , Sequence Alignment , Toxoplasma/chemistry , Toxoplasma/metabolism
12.
Mem Inst Oswaldo Cruz ; 104(2): 155-61, 2009 03.
Article in English | MEDLINE | ID: mdl-19430637

ABSTRACT

Parasite differentiation from proliferating tachyzoites into latent bradyzoites is central to pathogenesis and transmission of the intracellular protozoan pathogen Toxoplasma gondii. The presence of bradyzoite-containing cysts in human hosts and their subsequent rupture can cause life-threatening recrudescence of acute infection in the immunocompromised and cyst formation in other animals contributes to zoonotic transmission and widespread dissemination of the parasite. In this review, we discuss the evidence showing how the clinically relevant process of bradyzoite differentiation is regulated at both transcriptional and post-transcriptional levels. Specific regulatory factors implicated in modulating bradyzoite differentiation include promoter-based cis-elements, epigenetic modifications and protein translation control through eukaryotic initiation factor -2 (eIF2). In addition to a summary of the current state of knowledge in these areas we discuss the pharmacological ramifications and pose some questions for future research.


Subject(s)
Toxoplasma/pathogenicity , Animals , Cell Differentiation , Epigenesis, Genetic , Eukaryotic Initiation Factor-2/genetics , Eukaryotic Initiation Factor-2/metabolism , Humans , Protozoan Proteins/genetics , Protozoan Proteins/metabolism , Signal Transduction , Toxoplasma/cytology , Toxoplasma/genetics , Transcriptional Activation
SELECTION OF CITATIONS
SEARCH DETAIL