RESUMO
A long-standing debate exists among ecologists as to how diversity regulates infectious diseases (i.e., the nature of diversity-disease relationships); a dilution effect refers to when increasing host diversity inhibits infectious diseases (i.e., negative diversity-disease relationships). However, the generality, strength, and potential mechanisms underlying negative diversity-disease relationships in natural ecosystems remain unclear. To this end, we conducted a large-scale survey of 63 grassland sites across China to explore diversity-disease relationships. We found widespread negative diversity-disease relationships that were temperature-dependent; non-random diversity loss played a fundamental role in driving these patterns. Our study provides field evidence for the generality and temperature dependence of negative diversity-disease relationships in grasslands, becoming stronger in colder regions, while also highlighting the role of non-random diversity loss as a mechanism. These findings have important implications for community ecology, disease ecology, and epidemic control.
Assuntos
Biodiversidade , Pradaria , Doenças das Plantas , Temperatura , China , Doenças das Plantas/microbiologia , Fungos/fisiologia , Folhas de Planta/microbiologia , Poaceae/microbiologia , Poaceae/fisiologiaRESUMO
BACKGROUND: Adequate cough or exsufflation flow can indicate an option for safe tracheostomy decannulation to noninvasive management. Cough peak flow via the upper airways with the tube capped is an outcome predictor for decannulation readiness in patients with neuromuscular impairment. However, this threshold value is typically measured with tracheotomy tube removed, which is not acceptable culturally in China. The aim of this study was to assess the feasibility and safety of using cough flow measured with tracheostomy tube and speaking valve (CFSV) > 100 L/min as a cutoff value for decannulation. STUDY DESIGN: Prospective observational study conducted between January 2019 and September 2022 in a tertiary rehabilitation hospital. METHODS: Patients with prolonged tracheostomy tube placement were referred for screening. Each patient was assessed using a standardized tracheostomy decannulation protocol, in which CFSV greater than 100 L/min indicated that the patients' cough ability was sufficient for decannulation. Patients whose CFSV matched the threshold value and other protocol criteria were decannulated, and the reintubation and mortality rates were followed-up for 6 months. RESULTS: A total of 218 patients were screened and 193 patients were included. A total of 105 patients underwent decannulation, 103 patients were decannulated successfully, and 2 patients decannulated failure, required reinsertion of the tracheostomy tube within 48 h (failure rate 1.9%). Three patients required reinsertion or translaryngeal intubation within 6 months. CONCLUSIONS: CFSV greater than 100 L/min could be a reliable threshold value for successful decannulation in patients with various primary diseases with a tracheostomy tube. TRIAL REGISTRATION: This observational study was not registered online.
Assuntos
Respiração , Traqueostomia , Humanos , Intubação Intratraqueal , Pico do Fluxo Expiratório , Tosse/diagnóstico , Estudos RetrospectivosRESUMO
Early Parkinson's disease (PD) may cause respiratory dysfunction; however the findings vary among studies. The aim of the preliminary prospective observational study was to explore the deterioration of pulmonary function at various stages in patients with early PD. A total of 237 patients with PD were screened. Fifty-six patients were included (modified Hoehn and Yahr stage ≤ 2.5). In addition, 56 age-matched healthy controls were also included in the study. Significant differences between the PD and control groups were found in all the investigated lung-function parameters. The maximal voluntary ventilation (MVV) percent predicted was the only parameter that distinguished PD stages (101.1 ± 14.9% vs. 82.8 ± 19.2% vs. 71.4 ± 12.9%, Hoehn and Yahr stages 1.5 vs. 2 vs. 2.5, respectively; p < 0.005). MVV could be the most sensitive parameter for distinguishing the severity of early-stage PD.
Assuntos
Doença de Parkinson , Humanos , Pulmão , Ventilação Voluntária Máxima , Doença de Parkinson/complicações , Doença de Parkinson/diagnóstico , Estudos ProspectivosRESUMO
The aims of this study were to investigate the antioxidant, hypolipidemic and hepatic protective effects of Phascolosoma esculenta polysaccharides (PEP). PEP was prepared from Phascolosoma esculenta by enzyme hydrolysis and its characterization was analyzed. The antioxidant activities of PEP were evaluated by the assays of scavenging 1,1-Diphenyl-2-picrylhydrazyl (DPPH), superoxide anion, hydroxyl radicals and chelating ferrous ion in vitro. It showed that PEP could scavenge radicals effectively and had favorable antioxidant activities. In the meantime, the hypolipidemic effect of PEP was investigated in vivo by using mice model fed with high-fat diet with or without PEP treatment. Compared with the hyperlipidemic mice without treatment, the serum levels of total cholesterol (TC) (30.1-35.7%, p < 0.01), triglyceride (TG) (24.5-50.8%, p < 0.01 or p < 0.05), low-density lipoprotein cholesterol (LDL-C) (49.6-56.8%, p < 0.01) and liver levels of TC (21.0-28.4%, p < 0.01), TG (23.8-37.0%, p < 0.01) decreased significantly, whereas serum high-density lipoprotein cholesterol (HDL-C) (47.7-59.9%, p < 0.01 or p < 0.05) increased significantly after treatment with different dosage of PEP (0.2, 0.4 and 0.8 g per kg body weight, respectively). In addition, superoxide dismutase (SOD) (10.2-22.2% and 18.8-26.9%, p < 0.05), glutathione peroxidase (GSH-Px) (11.9-15.4% and 26.6-30.4%, p < 0.05) activities in serum and liver enhanced markedly while aspartate aminotransferase (AST) (18.7-29.6% and 42.4-58.0%, p < 0.05), alanine transaminase (ALT) (42.7-46.0% and 31.2-42.2%, p < 0.05) activities, as well as the levels of malondialdehyde (MDA) (15.9-24.4% and 15.0-16.8%, p < 0.01 or p < 0.05) in serum and liver reduced markedly. Moreover, the histopathological observation of livers indicated that PEP could attenuate liver cell injury. The animal experimental results demonstrated that PEP exerted hypolipidemic and hepatoprotective roles in hyperlipidemic mice. In summary, our results above suggest that PEP might be a potential natural antioxidant and utilized as a therapeutic candidate for hyperlipidemia.
Assuntos
Antioxidantes/farmacologia , Doença Hepática Induzida por Substâncias e Drogas/prevenção & controle , Hipolipemiantes/farmacologia , Polissacarídeos/farmacologia , Substâncias Protetoras/farmacologia , Animais , Peso Corporal/efeitos dos fármacos , Dieta Hiperlipídica , Sequestradores de Radicais Livres/química , Sequestradores de Radicais Livres/farmacologia , Quelantes de Ferro/farmacologia , Lipídeos/sangue , Masculino , Camundongos , Polissacarídeos/química , Polissacarídeos/uso terapêuticoRESUMO
OBJECTIVE: To investigate the risk factors for cow's milk protein allergy (CMPA) among infants through a multicenter clinical study. METHODS: A total of 1 829 infants, aged 1-12 months, who attended the outpatient service of the pediatric department in six hospitals in Shenzhen, China from June 2016 to May 2017 were enrolled as subjects. A questionnaire survey was performed to screen out suspected cases of CMPA. Food avoidance and oral food challenge tests were used to make a confirmed diagnosis of CMPA CMPA. A multivariate logistic regression analysis was used to investigate the risk factors for CMPA. RESULTS: Among the 1 829 infants, 82 (4.48%) were diagnosed with CMPA. The multivariate logistic regression analysis showed that maternal food allergy (OR=4.91, 95%CI: 2.24-10.76, P<0.05), antibiotic exposure during pregnancy (OR=3.18, 95%CI: 1.32-7.65, P<0.05), and the introduction of complementary food at an age of <4 months (OR=3.55, 95%CI: 1.52-8.27, P<0.05) were risk factors for CMPA, while exclusive breastfeeding (OR=0.21, 95%CI: 0.08-0.58, P<0.05) and the introduction of complementary food at an age of >6 months (OR=0.38, 95%CI: 0.17-0.86, P<0.05) were protective factors. CONCLUSIONS: The introduction of complementary food at an age of <4 months, maternal food allergy, and antibiotic exposure during pregnancy are risk factors for CMPA in infants.
Assuntos
Hipersensibilidade a Leite , Animais , Bovinos , China , Feminino , Humanos , Lactente , Proteínas do Leite , Gravidez , Fatores de Risco , Inquéritos e QuestionáriosRESUMO
PURPOSE: The SPARED CRN (Study of Prostate Ablation Related Energy Devices Coordinated Registry Network) is a private-public partnership between academic and community urologists, the FDA (U.S. Food and Drug Administration), the Medical Device Epidemiology Network and device manufacturers to examine the safety and effectiveness of technologies for partial gland ablation in men with localized prostate cancer. MATERIALS AND METHODS: We report on a recent workshop at the FDA with thought leaders to discuss a critical framework for partial gland ablation, focusing on patient selection, surgical planning, followup, study design and appropriate comparators in terms of adverse events and cancer control outcomes. We summarize salient points from experts in urology, oncology and epidemiology that were presented and discussed in an open forum. RESULTS: Given the challenges in achieving patient and physician equipoise to perform a randomized trial, as well as an inherent paradigm shift when comparing partial gland ablation (inability to assess prostate specific antigen recurrence) to whole gland treatments, the group focused on objective performance criteria and goals as a platform to guide the creation of single arm studies in the SPARED CRN. CONCLUSIONS: This summit lays the foundation for prospective, multi-center data collection and evaluation of novel medical devices and drug/device combinations for partial gland ablation.
Assuntos
Técnicas de Ablação/métodos , Previsões , Estadiamento de Neoplasias/métodos , Seleção de Pacientes , Prostatectomia/métodos , Neoplasias da Próstata/cirurgia , Biópsia , Seguimentos , Humanos , Imageamento por Ressonância Magnética/métodos , Masculino , Pessoa de Meia-Idade , Neoplasias da Próstata/diagnóstico , Sistema de Registros , Estudos RetrospectivosRESUMO
BACKGROUND Diabetic nephropathy (DN) is the leading cause of end-stage renal disease. Mesenchymal stem cells (MSCs) treatment has been proved to be effective in DN models by protecting renal function and preventing fibrosis. However, the underlying mechanism is unclear. Previous research indicated diabetes and associated complications may be attributed to failed resolution of inflammation, which is deliberately regulated by pro-resolving lipids, including lipoxins (LXs), resolvins (Rv) D and E series, protectins, and maresins. In this study, we monitored pro-resolving mediators in a DN model to explore the mechanism of MSCs treatment. MATERIAL AND METHODS The DN model was induced by STZ injection in SD rats. UPLC-MS/MS was performed to determine pro-resolving lipids in kidney tissue and serum of DN model before and after MSCs treatment, as well as in supernatants of HBZY-1-MSCs co-culture. RESULTS LXA4 was highly accumulated in renal tissue of DN rats with MSCs treatment; ex vivo, LXA4 was significantly increased in the supernatants of HBZY-1 cells co-cultured with MSCs in a high-glucose (HG) medium. Western blot analysis indicated that ALX/FPR2, the receptor of LXA4, was markedly expressed in renal tissue of the DN-MSC group and HBZY-1 after incubating with MSCs in HG. Intraperitoneal injection of LXA4 inhibited renal fibrosis by targeting TGF-ß/Smad signaling and downregulated serum TNF-alpha, IL-6, IL-8, and IFN-γ in DN rats. Notably, all the protective effects induced by MSCs or LXA4 were abolished by ALX/FRP2 blocking. CONCLUSIONS Our results demonstrate that MSCs intervention prevented DN procession via the LXA4-ALX/FPR2 axis, which inhibited glomerulosclerosis and pro-inflammatory cytokines, eventually contributing to kidney homeostasis.
Assuntos
Citocinas/metabolismo , Nefropatias Diabéticas/metabolismo , Nefropatias Diabéticas/terapia , Lipoxinas/metabolismo , Transplante de Células-Tronco Mesenquimais/métodos , Proteínas Smad/metabolismo , Fator de Crescimento Transformador beta/metabolismo , Animais , Diabetes Mellitus Experimental/complicações , Diabetes Mellitus Experimental/metabolismo , Diabetes Mellitus Experimental/patologia , Nefropatias Diabéticas/patologia , Ácidos Docosa-Hexaenoicos/metabolismo , Fibrose/metabolismo , Fibrose/patologia , Mediadores da Inflamação/metabolismo , Masculino , Células-Tronco Mesenquimais/citologia , Células-Tronco Mesenquimais/metabolismo , Ratos , Ratos Sprague-Dawley , Transdução de SinaisRESUMO
ß-N-Acetylglucosaminidases (NAGase) can remove N-acetylglucosamine (GlcNAc) from the non-reducing end of chitin or chitosan. GlcNAc has many important physiological functions in organism, which can be used for the treatment of rheumatoid arthritis clinically and be used as food antioxidant, infant food additive and diabetic sweetener. Thus, it is very important to develop genetic-engineering strains with high-yield NAGase to hydrolyze chitin into GlcNAc. Here, the NAGase gene of Bacillus subtilis 168 (BsnagZ) was synthesized according to the codon bias of Pichia pastoris and expressed in P. pastoris. The expression level of BsNagZ in P. pastoris increased over the induced time and the highest activity reached 0.76 U/mL at the 7th day. The recombinant BsNagZ was purified for characterization. The optimal temperature and pH are 60 °C and 6.0, respectively. It can both keep over 80% activities after pre-incubation at 55 °C for one hour and at 4 °C for 12 h from pH 4.5 to 10.0. To further improve the expression level of BsNagZ, a recombinant strain with four copy BsnagZs was screened using a high concentration of zeocin. The highest BsNagZ activity reached 3.2 U/mL at the 12th day, which was fourfold higher than that of single-copy strain. Combined with commercial chitinase CtnSg, GlcNAc can be produced by recombinant BsNagZ when used colloidal chitin as the substrate. Our study highlights that the NAGase was first successfully expressed in P. pastoris and GlcNAc can be produced via NAGase hydrolyzing the colloidal chitin.
Assuntos
Acetilglucosamina/química , Acetilglucosaminidase , Bacillus subtilis/genética , Proteínas de Bactérias , Expressão Gênica , Pichia , Acetilglucosaminidase/antagonistas & inibidores , Acetilglucosaminidase/química , Acetilglucosaminidase/genética , Bacillus subtilis/enzimologia , Proteínas de Bactérias/biossíntese , Proteínas de Bactérias/química , Proteínas de Bactérias/genética , Pichia/genética , Pichia/metabolismo , Proteínas Recombinantes/biossíntese , Proteínas Recombinantes/química , Proteínas Recombinantes/genéticaRESUMO
PURPOSE: The accumulation of data through a prospective, multicenter coordinated registry network is a practical way to gather real world evidence on the performance of novel prostate ablation technologies. Urological oncologists, targeted biopsy experts, industry representatives and representatives of the FDA (Food and Drug Administration) convened to discuss the role, feasibility and important data elements of a coordinated registry network to assess new and existing prostate ablation technologies. MATERIALS AND METHODS: A multiround Delphi consensus approach was performed which included the opinion of 15 expert urologists, representatives of the FDA and leadership from high intensity focused ultrasound device manufacturers. Stakeholders provided input in 3 consecutive rounds with conference calls following each round to obtain consensus on remaining items. Participants agreed that these elements initially developed for high intensity focused ultrasound are compatible with other prostate ablation technologies. Coordinated registry network elements were reviewed and supplemented with data elements from the FDA common study metrics. RESULTS: The working group reached consensus on capturing specific patient demographics, treatment details, oncologic outcomes, functional outcomes and complications. Validated health related quality of life questionnaires were selected to capture patient reported outcomes, including the IIEF-5 (International Index of Erectile Function-5), the I-PSS (International Prostate Symptom Score), the EPIC-26 (Expanded Prostate Cancer Index Composite-26) and the MSHQ-EjD (Male Sexual Health Questionnaire for Ejaculatory Dysfunction). Group consensus was to obtain followup multiparametric magnetic resonance imaging and prostate biopsy approximately 12 months after ablation with additional imaging or biopsy performed as clinically indicated. CONCLUSIONS: A national prostate ablation coordinated registry network brings forth vital practice pattern and outcomes data for this emerging treatment paradigm in the United States. Our multiple stakeholder consensus identifies critical elements to evaluate new and existing energy modalities and devices.
Assuntos
Próstata/cirurgia , Neoplasias da Próstata/cirurgia , Sistema de Registros , Ressecção Transuretral da Próstata/estatística & dados numéricos , Biópsia/normas , Consenso , Técnica Delphi , Estudos de Viabilidade , Humanos , Imageamento por Ressonância Magnética/métodos , Imageamento por Ressonância Magnética/normas , Imagem por Ressonância Magnética Intervencionista/métodos , Imagem por Ressonância Magnética Intervencionista/normas , Masculino , Medidas de Resultados Relatados pelo Paciente , Cuidados Pós-Operatórios/métodos , Cuidados Pós-Operatórios/normas , Estudos Prospectivos , Próstata/diagnóstico por imagem , Próstata/patologia , Neoplasias da Próstata/patologia , Qualidade de Vida , Ressecção Transuretral da Próstata/métodos , Ressecção Transuretral da Próstata/normas , Estados UnidosRESUMO
Malaria elimination strategies require surveillance of the parasite population for genetic changes that demand a public health response, such as new forms of drug resistance. Here we describe methods for the large-scale analysis of genetic variation in Plasmodium falciparum by deep sequencing of parasite DNA obtained from the blood of patients with malaria, either directly or after short-term culture. Analysis of 86,158 exonic single nucleotide polymorphisms that passed genotyping quality control in 227 samples from Africa, Asia and Oceania provides genome-wide estimates of allele frequency distribution, population structure and linkage disequilibrium. By comparing the genetic diversity of individual infections with that of the local parasite population, we derive a metric of within-host diversity that is related to the level of inbreeding in the population. An open-access web application has been established for the exploration of regional differences in allele frequency and of highly differentiated loci in the P. falciparum genome.
Assuntos
Biodiversidade , Sequenciamento de Nucleotídeos em Larga Escala , Malária Falciparum/parasitologia , Plasmodium falciparum/genética , Alelos , Genoma de Protozoário , Genótipo , Humanos , Filogenia , Plasmodium falciparum/classificação , Polimorfismo de Nucleotídeo Único , Análise de Componente PrincipalRESUMO
Diabetic nephropathy as the most common cause of end-stage renal disease accounts for a significant increase in morbidity and mortality in patients. Epithelial to mesenchymal transition (EMT) of tubular cells is associated with diabetic nephropathy. Advanced glycation end products (AGEs) are thought to be involved in the pathogenesis of diabetic nephropathy via multifactorial mechanisms. However, whether AGEs could induce EMT in Tubular epithelial cells is still unknown. In this study, we found that AGEs induced EMT and accompanied by reduced expression of the epithelial markers E-cadherin and enhanced expression of the mesenchymal markers vimentin and alpha-smooth muscle actin. Furthermore, the expression of HMGA2 was upregulated by AGEs. Far more interesting, its knockdown by short interfering RNA (siRNA) effectively reversed AGEs-induced EMT. Meanwhile, we also found that knockdown of HMGA2 inhibited high AGEs-induced generation of reactive oxygen species (ROS) and the activation of p38 MAPK. Collectively, these studies suggest that HMGA2 plays a important role in EMT during Diabetic nephropathy and more study toward HMGA2 should be played in renal pathogenesis.
Assuntos
Células Epiteliais/metabolismo , Transição Epitelial-Mesenquimal , Produtos Finais de Glicação Avançada/metabolismo , Proteína HMGA2/genética , RNA Interferente Pequeno/genética , Animais , Linhagem Celular , Proteína HMGA2/metabolismo , Ratos , Regulação para Cima , Proteínas Quinases p38 Ativadas por Mitógeno/metabolismoRESUMO
Several empirical studies, particularly those conducted in developed countries, have linked social support to quality of life among persons living with HIV/AIDS (PLWA). However, few studies have been conducted in developing countries, such as China; therefore, the question of any association being present between social support and quality of life in PLWA in China remains unanswered. This retrospective cross-sectional study was conducted to examine the relationships between social support and quality of life among PLWA in the Jiangxi and Zhejiang provinces of China. A total of 377 PLWA participated in this study, and questionnaires used included demographics, the Chinese Medical Outcomes Study Short Form-36, and a Social Support Rating Scale, all of which were collected through face-to-face interviews between 1 March and 15 April 2013 in six different County Centers of Disease Control and Prevention in Jiangxi and Zhejiang provinces, and one hospital in the Jiangxi. The health-related quality of life score was 64.7±13.5 (out of a total score of 100), which was significantly lower than the national norm level of 78.2±15.9. The total score of social support was 29.4±7.8 (full score 66). The canonical correlation between social support and quality of participants' lives was shown to be statistically significant (p<0.0001). The relationship between subjective support and quality of life among PLWA was also significant (p=0.004). Subjective support and the use of social support showed a positive correlation with vitality, role-physical, and role-emotional, and a negative correlation with body pain. The current study suggests that PLWA with lower social support have diminished quality of life.
Assuntos
Infecções por HIV/psicologia , Qualidade de Vida , Apoio Social , Adaptação Psicológica , Adulto , China/epidemiologia , Estudos Transversais , Feminino , Infecções por HIV/epidemiologia , Humanos , Masculino , Pessoa de Meia-Idade , Escalas de Graduação Psiquiátrica , Estudos Retrospectivos , Fatores Socioeconômicos , Inquéritos e Questionários , Adulto JovemRESUMO
BACKGROUND: Vibration response imaging (VRI) is a new technology for lung imaging. Active smokers and non-smokers show differences in VRI findings, but no data are available for passive smokers. The aim of this study was to evaluate the use of VRI and to assess the differences in VRI findings among non-smokers, active smokers, and passive smokers. MATERIAL AND METHODS: Healthy subjects (n=165: 63 non-smokers, 56 active smokers, and 46 passive smokers) with normal lung function were enrolled. Medical history, physical examination, lung function test, and VRI were performed for all subjects. Correlation between smoking index and VRI scores (VRIS) were performed. RESULTS: VRI images showed progressive and regressive stages representing the inspiratory and expiratory phases bilaterally in a vertical and synchronized manner in non-smokers. Vibration energy curves with low expiratory phase and plateau were present in 6.35% and 3.17%, respectively, of healthy non-smokers, 41.07% and 28.60% of smokers, and 39.13% and 30.43% of passive smokers, respectively. The massive energy peak in the non-smokers, smokers, and passive-smokers was 1.77±0.27, 1.57±0.29, and 1.66±0.33, respectively (all P<0.001). A weak but positive correlation was observed between VRIS and smoking index. CONCLUSIONS: VRI can intuitively show the differences between non-smokers and smokers. VRI revealed that passive smoking can also harm the lungs. VRI could be used to visually persuade smokers to give up smoking.
Assuntos
Pulmão/patologia , Fumar/patologia , Poluição por Fumaça de Tabaco , Adulto , Diagnóstico por Imagem/métodos , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Estudos Prospectivos , Testes de Função Respiratória , VibraçãoRESUMO
OBJECTIVE: To explore the change in serum adiponectin levels and its significance in children with Kawasaki disease (KD). METHODS: Forty-five KD patients were enrolled in this study, including 18 with coronary artery lesions (CAL group) and 27 without coronary artery lesions (NCAL group). Twenty healthy children were recruited to the control group. Enzyme-linked immunosorbent assay was used to measure serum adiponectin levels, and an automatic biochemical analyzer was used to measure the levels of triglyceride (TG), total cholesterol (TC), low-density lipoprotein cholesterol (LDL-C), and high-density lipoprotein cholesterol (HDL-C). RESULTS: The serum adiponectin levels in the CAL and NCAL groups were significantly lower than in the control group during the acute phase, subacute phase, and recovery phase (P<0.01), with lower levels observed during the acute phase and subacute phase (P<0.01). Compared with the NCAL group, the CAL group had significantly higher serum levels of adiponectin during the acute phase and recovery phase (P<0.05). The levels of TC, HDL, and LDL in the NCAL and CAL groups were significantly lower than in the control group (P<0.05). The levels of serum adiponectin in KD patients were positively correlated with the levels of TC, TG, and C-reactive protein and the occurrence of CAL (r=0.31, 0.30, 0.34, and 0.35, respectively; P<0.05). CONCLUSIONS: Children with KD have metabolic disorders of blood lipids and reduced serum adiponectin levels. Reduced serum adiponectin levels may be the result of systemic inflammation, while increased adiponectin levels may be closely associated with the occurrence of CAL.
Assuntos
Adiponectina/sangue , Síndrome de Linfonodos Mucocutâneos/sangue , Criança , Pré-Escolar , Doença da Artéria Coronariana/sangue , Feminino , Humanos , Lactente , Lipídeos/sangue , MasculinoRESUMO
Malaria transmission requires the production of male and female gametocytes in the human host followed by fertilization and sporogonic development in the mosquito midgut. Although essential for the spread of malaria through the population, little is known about the initiation of gametocytogenesis in vitro or in vivo. Using a gametocyte-defective parasite line and genetic complementation, we show that Plasmodium falciparumgametocyte development 1 gene (Pfgdv1), encoding a peri-nuclear protein, is critical for early sexual differentiation. Transcriptional analysis of Pfgdv1 negative and positive parasite lines identified a set of gametocytogenesis early genes (Pfge) that were significantly down-regulated (>10 fold) in the absence of Pfgdv1 and expression was restored after Pfgdv1 complementation. Progressive accumulation of Pfge transcripts during successive rounds of asexual replication in synchronized cultures suggests that gametocytes are induced continuously during asexual growth. Comparison of Pfge gene transcriptional profiles in patient samples divided the genes into two groups differing in their expression in mature circulating gametocytes and providing candidates to evaluate gametocyte induction and maturation separately in vivo. The expression profile of one of the early gametocyte specific genes, Pfge1, correlated significantly with asexual parasitemia, which is consistent with the ongoing induction of gametocytogenesis during asexual growth observed in vitro and reinforces the need for sustained transmission-blocking strategies to eliminate malaria.
Assuntos
Genes de Protozoários , Malária/parasitologia , Plasmodium falciparum/crescimento & desenvolvimento , Plasmodium falciparum/genética , Proteínas de Protozoários/genética , Proteínas de Protozoários/metabolismo , Regulação da Expressão Gênica no Desenvolvimento , Humanos , Malária/transmissão , Parasitemia , Plasmodium falciparum/metabolismo , Proteínas de Protozoários/sangue , Reprodução Assexuada , Transcrição Gênica , TranscriptomaRESUMO
Plasmodium yoelii is an excellent model for studying malaria pathogenesis that is often intractable to investigate using human parasites; however, genetic studies of the parasite have been hindered by lack of genome-wide linkage resources. Here, we performed 14 genetic crosses between three pairs of P. yoelii clones/subspecies, isolated 75 independent recombinant progeny from the crosses, and constructed a high-resolution linkage map for this parasite. Microsatellite genotypes from the progeny formed 14 linkage groups belonging to the 14 parasite chromosomes, allowing assignment of sequence contigs to chromosomes. Growth-related virulent phenotypes from 25 progeny of one of the crosses were significantly associated with a major locus on chromosome 13 and with two secondary loci on chromosomes 7 and 10. The chromosome 10 and 13 loci are both linked to day 5 parasitemia, and their effects on parasite growth rate are independent but additive. The locus on chromosome 7 is associated with day 10 parasitemia. The chromosome 13 locus spans ~220 kb of DNA containing 51 predicted genes, including the P. yoelii erythrocyte binding ligand, in which a C741Y substitution in the R6 domain is implicated in the change of growth rate. Similarly, the chromosome 10 locus spans ~234 kb with 71 candidate genes, containing a member of the 235-kDa rhoptry proteins (Py235) that can bind to the erythrocyte surface membrane. Atypical virulent phenotypes among the progeny were also observed. This study provides critical tools and information for genetic investigations of virulence and biology of P. yoelii.
Assuntos
Mapeamento Cromossômico/métodos , Genes de Protozoários/genética , Genoma de Protozoário/genética , Plasmodium yoelii/genética , Animais , Cromossomos/genética , Eritrócitos/parasitologia , Feminino , Malária/parasitologia , Camundongos , Camundongos Endogâmicos C57BL , Mutação , Filogenia , Plasmodium yoelii/classificação , Plasmodium yoelii/patogenicidade , Especificidade da Espécie , Virulência/genéticaRESUMO
Osteoarthritis (OA) is the most prevalent joint disease in the elderly population and its substantial morbidity and disability impose a heavy economic burden on patients and society. Knee osteoarthritis (KOA) is the most common subtype of OA, which is characterized by damage to progressive articular cartilage, synovitis, and subchondral bone sclerosis. Most current treatments for OA are palliative, primarily aim at symptom management, and do not prevent the progression of the disease or restore degraded cartilage. The activation of α-granules in platelets releases various growth factors that are involved in multiple stages of tissue repair, suggesting potential for disease modification. In recent years, platelet-based therapies, such as platelet-rich plasma, platelet-rich fibrin, and platelet lysates, have emerged as promising regenerative treatments for KOA, but their related effects and mechanisms are still unclear. Therefore, this review aims to summarize the biological characteristics and functions of platelets, classify the products of platelet-based therapy and related preparation methods. Moreover, we summarize the basic research of platelet-based regeneration strategies for KOA and discuss the cellular effects and molecular mechanisms. Further, we describe the general clinical application of platelet-based therapy in the treatment of KOA and the results of the meta-analysis of randomized controlled trials.
RESUMO
The recent reports of artemisinin (ART) resistance in the Thai-Cambodian border area raise a serious concern on the long-term efficacy of ARTs. To elucidate the resistance mechanisms, we performed in vitro selection with dihydroartemisinin (DHA) and obtained two parasite clones from Dd2 with more than 25-fold decrease in susceptibility to DHA. The DHA-resistant clones were more tolerant of stressful growth conditions and more resistant to several commonly used antimalarial drugs than Dd2. The result is worrisome as many of the drugs are currently used as ART partners in malaria control. This study showed that the DHA resistance is not limited to ring stage, but also occurred in trophozoites and schizonts. Microarray and biochemical analyses revealed pfmdr1 amplification, elevation of the antioxidant defence network, and increased expression of many chaperones in the DHA-resistant parasites. Without drug pressure, the DHA-resistant parasites reverted to sensitivity in approximately 8 weeks, accompanied by de-amplification of pfmdr1 and reduced antioxidant activities. The parallel decrease and increase in pfmdr1 copy number and antioxidant activity and the up and down of DHA sensitivity strongly suggest that pfmdr1 and antioxidant defence play a role in in vitro resistance to DHA, providing potential molecular markers for ART resistance.