Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 413
Filtrar
Mais filtros

Tipo de documento
Intervalo de ano de publicação
1.
J Physiol ; 2023 Jan 04.
Artigo em Inglês | MEDLINE | ID: mdl-36597809

RESUMO

Age-related decline in skeletal muscle structure and function can be mitigated by regular exercise. However, the precise mechanisms that govern this are not fully understood. The nucleus plays an active role in translating forces into biochemical signals (mechanotransduction), with the nuclear lamina protein lamin A regulating nuclear shape, nuclear mechanics and ultimately gene expression. Defective lamin A expression causes muscle pathologies and premature ageing syndromes, but the roles of nuclear structure and function in physiological ageing and in exercise adaptations remain obscure. Here, we isolated single muscle fibres and carried out detailed morphological and functional analyses on myonuclei from young and older exercise-trained individuals. Strikingly, myonuclei from trained individuals were more spherical, less deformable, and contained a thicker nuclear lamina than those from untrained individuals. Complementary to this, exercise resulted in increased levels of lamin A and increased myonuclear stiffness in mice. We conclude that exercise is associated with myonuclear remodelling, independently of age, which may contribute to the preservative effects of exercise on muscle function throughout the lifespan. KEY POINTS: The nucleus plays an active role in translating forces into biochemical signals. Myonuclear aberrations in a group of muscular dystrophies called laminopathies suggest that the shape and mechanical properties of myonuclei are important for maintaining muscle function. Here, striking differences are presented in myonuclear shape and mechanics associated with exercise, in both young and old humans. Myonuclei from trained individuals were more spherical, less deformable and contained a thicker nuclear lamina than untrained individuals. It is concluded that exercise is associated with age-independent myonuclear remodelling, which may help to maintain muscle function throughout the lifespan.

2.
Opt Express ; 31(10): 16295-16302, 2023 May 08.
Artigo em Inglês | MEDLINE | ID: mdl-37157711

RESUMO

We experimentally investigate the spectral broadening in fused silica in the multiphoton absorption regime. Under standard conditions of laser irradiation, linear polarization of laser pulses is more advantageous for supercontinuum generation. However, with high non-linear absorption, we observe more efficient spectral broadening for circular polarizations for both Gaussian and doughnut-shaped beams. The multiphoton absorption in fused silica is studied by measuring the total transmission of laser pulses and by the intensity dependence of the self-trapped exciton luminescence observation. The strong polarization dependence of multiphoton transitions fundamentally affects the broadening of the spectrum in solids.

3.
Org Biomol Chem ; 21(27): 5648-5657, 2023 Jul 12.
Artigo em Inglês | MEDLINE | ID: mdl-37394986

RESUMO

We describe for the first time the co-existence of the parallel and antiparallel conformation of the heterodimeric E3/K3 and E3/R3 coiled-coil systems in solution. The introduction of a furanylated amino acid in the (EIAALEK)3 sequence allowed, upon photo-induced covalent crosslinking, freezing of the respective coiled-coil complexes present in solution. The occurrence of both parallel and antiparallel conformations in solution was supported by computational simulations and further confirmed by fluorescence experiments based on pyrene-pyrene stacking.

4.
J Virol ; 95(9)2021 04 12.
Artigo em Inglês | MEDLINE | ID: mdl-33568510

RESUMO

In this placebo-controlled phase II randomized clinical trial, 103 human immunodeficiency virus type 1 (HIV-1)-infected patients under cART (combined antiretroviral treatment) were randomized 2:1 to receive either 3 doses of DNA GTU-MultiHIV B (coding for Rev, Nef, Tat, Gag, and gp160) at week 0 (W0), W4, and W12, followed by 2 doses of LIPO-5 vaccine containing long peptides from Gag, Pol, and Nef at W20 and W24, or placebo. Analytical treatment interruption (ATI) was performed between W36 to W48. At W28, vaccinees experienced an increase in functional CD4+ T-cell responses (P < 0.001 for each cytokine compared to W0) measured, predominantly against Gag and Pol/Env, and an increase in HIV-specific CD8+ T cells producing interleukin 2 (IL-2) and tumor necrosis factor alpha (TNF-α) (P = 0.001 and 0.013, respectively), predominantly against Pol/Env and Nef. However, analysis of T-cell subsets by mass cytometry in a subpopulation showed an increase in the W28/W0 ratio for memory CD8+ T cells coexpressing exhaustion and senescence markers such as PD-1/TIGIT (P = 0.004) and CD27/CD57 (P = 0.044) in vaccinees compared to the placebo group. During ATI, all patients experienced viral rebound, with the maximum observed HIV RNA level at W42 (median, 4.63 log10 copies [cp]/ml; interquartile range [IQR], 4.00 to 5.09), without any difference between arms. No patient resumed cART for CD4 cell count drop. Globally, the vaccine strategy was safe. However, a secondary HIV transmission during ATI was observed. These data show that the prime-boost combination of DNA and LIPO-5 vaccines elicited broad and polyfunctional T cells. The contrast between the quality of immune responses and the lack of potent viral control underscores the need for combined immunomodulatory strategies. (This study has been registered at ClinicalTrials.gov under registration no. NCT01492985.)IMPORTANCE In this placebo-controlled phase II randomized clinical trial, we evaluated the safety and immunogenicity of a therapeutic prime-boost vaccine strategy using a recombinant DNA vaccine (GTU-MultiHIV B clade) followed by a boost vaccination with a lipopeptide vaccine (HIV-LIPO-5) in HIV-infected patients on combined antiretroviral therapy. We show here that this prime-boost strategy is well tolerated, consistently with previous studies in HIV-1-infected individuals and healthy volunteers who received each vaccine component individually. Compared to the placebo group, vaccinees elicited strong and polyfunctional HIV-specific CD4+ and CD8+ T-cell responses. However, these immune responses presented some qualitative defects and were not able to control viremia following antiretroviral treatment interruption, as no difference in HIV viral rebound was observed in the vaccine and placebo groups. Several lessons were learned from these results, pointing out the urgent need to combine vaccine strategies with other immune-based interventions.


Assuntos
Vacinas contra a AIDS , Antirretrovirais/uso terapêutico , Infecções por HIV/terapia , Vacinas de DNA , Vacinas contra a AIDS/administração & dosagem , Vacinas contra a AIDS/imunologia , Adulto , Linfócitos T CD4-Positivos/citologia , Linfócitos T CD4-Positivos/imunologia , Linfócitos T CD8-Positivos/citologia , Linfócitos T CD8-Positivos/imunologia , Feminino , Infecções por HIV/imunologia , HIV-1/efeitos dos fármacos , Humanos , Imunização Secundária , Masculino , Pessoa de Meia-Idade , Vacinas de DNA/administração & dosagem , Vacinas de DNA/imunologia
5.
Clin Genet ; 91(6): 902-907, 2017 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-27808398

RESUMO

Mutations of several genes have been implicated in autosomal recessive osteopetrosis (OP), a disease caused by impaired function and differentiation of osteoclasts. Severe combined immune deficiencies (SCID) can likewise result from different genetic mutations. We report two siblings with SCID and an atypical phenotype of OP. A biallelic microdeletion encompassing the 5' region of TRAF6, RAG1 and RAG2 genes was identified. TRAF6, a tumor necrosis factor receptor-associated family member, plays an important role in T cell signaling and in RANKL-dependent osteoclast differentiation and activation but its role in human OP has not been previously reported. The RAG proteins are essential for recombination of B and T cell receptors, and for the survival and differentiation of these cells. This is the first study to report a homozygous deletion of TRAF6 as a cause of human disease.


Assuntos
Proteínas de Ligação a DNA/genética , Proteínas de Homeodomínio/genética , Proteínas Nucleares/genética , Osteopetrose/genética , Imunodeficiência Combinada Severa/genética , Fator 6 Associado a Receptor de TNF/genética , Regiões 5' não Traduzidas/genética , Diferenciação Celular/genética , Feminino , Predisposição Genética para Doença , Homozigoto , Humanos , Lactente , Recém-Nascido , Peptídeos e Proteínas de Sinalização Intracelular , Masculino , Mutação , Osteoclastos/metabolismo , Osteopetrose/patologia , Receptores de Antígenos de Linfócitos T/genética , Deleção de Sequência/genética , Imunodeficiência Combinada Severa/patologia , Transdução de Sinais/genética
6.
Lupus ; 26(5): 470-477, 2017 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-28394237

RESUMO

Animal models are a key element in disease research and treatment. In the field of neuropsychiatric lupus research, inbred, transgenic and disease-induced mice provide an opportunity to study the pathogenic routes of this multifactorial illness. In addition to achieving a better understanding of the immune mechanisms underlying the disease onset, supplementary metabolic and endocrine influences have been discovered and investigated. The ever-expanding knowledge about the pathologic events that occur at disease inception enables us to explore new drugs and therapeutic approaches further and to test them using the same animal models. Discovery of the molecular targets that constitute the pathogenic basis of the disease along with scientific advancements allow us to target these molecules with monoclonal antibodies and other specific approaches directly. This novel therapy, termed "targeted biological medication" is a promising endeavor towards producing drugs that are more effective and less toxic. Further work to discover additional molecular targets in lupus' pathogenic mechanism and to produce drugs that neutralize their activity is needed to provide patients with safe and efficient methods of controlling and treating the disease.


Assuntos
Modelos Animais de Doenças , Vasculite Associada ao Lúpus do Sistema Nervoso Central/patologia , Animais , Animais Geneticamente Modificados , Autoanticorpos/metabolismo , Citocinas/metabolismo , Predisposição Genética para Doença , Humanos , Vasculite Associada ao Lúpus do Sistema Nervoso Central/genética , Vasculite Associada ao Lúpus do Sistema Nervoso Central/metabolismo , Camundongos
7.
Int J Clin Pract ; 69(4): 501-8, 2015 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-25311361

RESUMO

AIMS: This study addresses the common practice of providing aggressive treatments of limited clinical benefit and cost-effectiveness to seriously ill and frail elderly. We have created a statistical model of 6-month mortality risk prediction following acute hospitalisation admission, and identified a subset of patients with poorest prognosis that requires comfort-focused care. METHODS: We have studied electronic medical records of 26,937 patients age 65 years or older, hospitalised in the internal medicine departments of one tertiary-care teaching medical center in Northern Israel from January 1, 2008 through December 31, 2011 and mortality data from the Israeli Internal Ministry Registry. Norton score records were employed for the performance status evaluation. Multivariate logistic regression analysis was used to predict the risk of 6-month mortality. RESULTS: Variables associated with an increased risk of 6-month mortality included: metastatic cancer, age above 85 years, decreased values of blood albumin and haemoglobin, increased blood urea nitrogen and decreased physical/mental status and activity. The receiver operating characteristic area for the predicted probability of death was 0.845 and 0.847 in external validation cohort. Using predictive values of the logistic regression analysis, the study cohort was stratified into six groups with various predictive mortality risks. CONCLUSION: The majority of deaths that have occurred within 6 months following the acute hospitalisation could be predicted on patient admission based on a few simple and easily obtained parameters. Earlier recognition of patients nearing the end of their lives may lead to better care and more efficient use of available resource.


Assuntos
Doença Aguda/mortalidade , Mortalidade Hospitalar , Medição de Risco/métodos , Idoso , Idoso de 80 Anos ou mais , Estudos de Coortes , Feminino , Idoso Fragilizado , Humanos , Medicina Interna/estatística & dados numéricos , Israel/epidemiologia , Modelos Logísticos , Masculino , Assistência Centrada no Paciente/métodos , Valor Preditivo dos Testes , Prognóstico , Fatores de Risco
8.
Adv Exp Med Biol ; 832: 25-33, 2015.
Artigo em Inglês | MEDLINE | ID: mdl-25300686

RESUMO

We have previously shown that green tea (GT) drinking combined with vitamin E supplementation reduced plasma protein carbonyls and increased erythrocytes catalase activity in exercising healthy elderly. In the present study we set out to investigate the antioxidative effects of GT drinking in an aging population. We performed an interventional, crossover, controlled prospective trial with 35 healthy elderly subjects (mean age 67.3±4.8 years), supplemented with four daily placebo maltodextrin "tea-bags" for 12 weeks, followed by four 1.5 g daily GT bags for another 12 weeks. Data were obtained at baseline, at the end of the placebo period, and at the end of the GT intervention period. We found that GT did not alter erythrocyte catalase activity. However, it provided protection against 2,2'-azobis (2-amidinopropane) dihydrochloride (AAPH)-induced oxidative hemolysis which declined by 10.2% (p<0.001). No changes were observed in saliva oral peroxidase enzymes. Nonetheless, saliva total antioxidant capacity increased by 42.0% (p<0.01). Plasma oxidative products, such as protein carbonyls, lipid peroxides and thiobarbituric acid reactive substances (TBARS) were stable throughout the intervention period. We conclude that four daily cups of GT are well tolerated in elderly free living subjects. Our results demonstrate that both erythrocyte resistances to oxidation and saliva antioxidant capacity are improved by GT drinking. The clinical implications of these oxidation modifications require further research.


Assuntos
Envelhecimento/sangue , Antioxidantes/metabolismo , Eritrócitos/metabolismo , Saliva/química , Chá , Idoso , Amidinas/farmacologia , Células Cultivadas , Estudos Cross-Over , Eritrócitos/efeitos dos fármacos , Feminino , Humanos , Peroxidação de Lipídeos , Masculino , Pessoa de Meia-Idade , Oxidantes/farmacologia , Oxirredução , Peroxidases/metabolismo , Estudos Prospectivos , Carbonilação Proteica , Substâncias Reativas com Ácido Tiobarbitúrico/metabolismo
9.
HIV Med ; 15(1): 23-9, 2014 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-24007426

RESUMO

OBJECTIVES: Interleukin-2 (IL-2) therapy increased CD4 cell counts and delayed antiretroviral therapy (ART) initiation in HIV-infected patients in the Agence Nationale de Recherche sur le SIDA et les Hépatites Virales (ANRS) 119 trial. However, four cases of lymphoma were reported. Epstein-Barr virus (EBV) replication is associated with an increased risk of lymphoma in immunocompromised patients. We assessed whether IL-2 had an impact on EBV replication and the development of lymphoma. METHODS: A total of 130 ART-naïve patients were randomized to receive IL-2 therapy (n = 66) or no treatment (n = 64). Clinical data for patients with lymphomas were reviewed and tumours assessed for evidence of EBV infection and CD25 (the IL-2 receptor) expression. EBV DNA levels were measured in whole blood and plasma in both arms using real-time polymerase chain reaction (PCR), up to 48 weeks after baseline (BL). RESULTS: Four lymphomas occurred, a median of 61 weeks [range 40-94 weeks] after randomization at a median CD4 cell count of 396 cells/µL (IQR 234-536 cells/µL). In the IL-2 arm, two patients developed EBV-positive Hodgkin's lymphoma, and one developed EBV-negative Burkitt-type lymphoma. One patient in the control group developed EBV-positive non-Hodgkin's lymphoma. CD25 was negative in all cases. Among the 41 of 55 (control arm) and 44 of 58 (IL-2 arm) patients with detectable EBV DNA in whole blood at both BL and week 48, the median change in EBV DNA between BL and week 48 was +0.04 log10 copies/ml in both arms (P = 0.7). In plasma, EBV was detected at least once in 22 of 52 controls and 21 of 54 IL-2-treated patients (P = 0.8). CONCLUSIONS: IL-2 therapy had no significant effect on EBV replication over 48 weeks in these ART-naïve patients. The occurrence of lymphomas did not seem to be associated with IL-2 therapy.


Assuntos
Fármacos Anti-HIV/uso terapêutico , Linfoma de Burkitt/virologia , Infecções por HIV/tratamento farmacológico , HIV-1 , Herpesvirus Humano 4/genética , Doença de Hodgkin/virologia , Interleucina-2/uso terapêutico , Adulto , Fármacos Anti-HIV/efeitos adversos , Linfoma de Burkitt/sangue , Contagem de Linfócito CD4 , DNA Viral/sangue , DNA Viral/efeitos dos fármacos , Infecções por Vírus Epstein-Barr/sangue , Infecções por Vírus Epstein-Barr/complicações , Infecções por Vírus Epstein-Barr/virologia , Feminino , Infecções por HIV/complicações , Herpesvirus Humano 4/isolamento & purificação , Doença de Hodgkin/sangue , Humanos , Incidência , Interleucina-2/efeitos adversos , Masculino , Pessoa de Meia-Idade , Carga Viral/efeitos dos fármacos
11.
Clin Infect Dis ; 55(2): 291-300, 2012 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-22550117

RESUMO

BACKGROUND: The immune deficiency of human immunodeficiency virus (HIV) infection is not fully corrected with ARV therapy. Interleukin-7 (IL-7) can boost CD4 T-cell counts, but optimal dosing and mechanisms of cellular increases need to be defined. METHODS: We performed a randomized placebo-controlled dose escalation (10, 20 and 30 µg/kg) trial of 3 weekly doses of recombinant human IL-7 (rhIL-7) in ARV-treated HIV-infected persons with CD4 T-cell counts between 101 and 400 cells/µL and plasma HIV levels <50 copies/mL. Toxicity, activity and the impact of rhIL-7 on immune reconstitution were monitored. RESULTS: Doses of rhIL-7 up to 20 µg/kg were well tolerated. CD4 increases of predominantly naive and central memory T cells were brisk (averaging 323 cells/µL at 12 weeks) and durable (up to 1 year). Increased cell cycling and transient increased bcl-2 expression were noted. Expanded cells did not have the characteristics of regulatory or activated T cells. Transient low-level HIV viremia was seen in 6 of 26 treated patients; modest increases in total levels of intracellular HIV DNA were proportional to CD4 T-cell expansions. IL-7 seemed to increase thymic output and tended to improve the T-cell receptor (TCR) repertoire in persons with low TCR diversity. CONCLUSIONS: Three weekly doses of rhIL-7 at 20 µg/kg are well tolerated and lead to a dose-dependent CD4 T-cell increase and the broadening of TCR diversity in some subjects. These data suggest that this rhIL-7 dose could be advanced in future rhIL-7 clinical studies. CLINICAL TRIALS REGISTRATION: NCT0047732.


Assuntos
Fármacos Anti-HIV/administração & dosagem , Terapia Antirretroviral de Alta Atividade/métodos , Linfócitos T CD4-Positivos/imunologia , Infecções por HIV/tratamento farmacológico , Infecções por HIV/imunologia , Fatores Imunológicos/administração & dosagem , Interleucina-7/administração & dosagem , Contagem de Linfócito CD4 , Humanos , Fatores Imunológicos/efeitos adversos , Interleucina-7/efeitos adversos , Placebos/administração & dosagem , Proteínas Recombinantes/administração & dosagem , Proteínas Recombinantes/efeitos adversos , Resultado do Tratamento
12.
N Engl J Med ; 361(16): 1548-59, 2009 Oct 15.
Artigo em Inglês | MEDLINE | ID: mdl-19828532

RESUMO

BACKGROUND: Used in combination with antiretroviral therapy, subcutaneous recombinant interleukin-2 raises CD4+ cell counts more than does antiretroviral therapy alone. The clinical implication of these increases is not known. METHODS: We conducted two trials: the Subcutaneous Recombinant, Human Interleukin-2 in HIV-Infected Patients with Low CD4+ Counts under Active Antiretroviral Therapy (SILCAAT) study and the Evaluation of Subcutaneous Proleukin in a Randomized International Trial (ESPRIT). In each, patients infected with the human immunodeficiency virus (HIV) who had CD4+ cell counts of either 50 to 299 per cubic millimeter (SILCAAT) or 300 or more per cubic millimeter (ESPRIT) were randomly assigned to receive interleukin-2 plus antiretroviral therapy or antiretroviral therapy alone. The interleukin-2 regimen consisted of cycles of 5 consecutive days each, administered at 8-week intervals. The SILCAAT study involved six cycles and a dose of 4.5 million IU of interleukin-2 twice daily; ESPRIT involved three cycles and a dose of 7.5 million IU twice daily. Additional cycles were recommended to maintain the CD4+ cell count above predefined target levels. The primary end point of both studies was opportunistic disease or death from any cause. RESULTS: In the SILCAAT study, 1695 patients (849 receiving interleukin-2 plus antiretroviral therapy and 846 receiving antiretroviral therapy alone) who had a median CD4+ cell count of 202 cells per cubic millimeter were enrolled; in ESPRIT, 4111 patients (2071 receiving interleukin-2 plus antiretroviral therapy and 2040 receiving antiretroviral therapy alone) who had a median CD4+ cell count of 457 cells per cubic millimeter were enrolled. Over a median follow-up period of 7 to 8 years, the CD4+ cell count was higher in the interleukin-2 group than in the group receiving antiretroviral therapy alone--by 53 and 159 cells per cubic millimeter, on average, in the SILCAAT study and ESPRIT, respectively. Hazard ratios for opportunistic disease or death from any cause with interleukin-2 plus antiretroviral therapy (vs. antiretroviral therapy alone) were 0.91 (95% confidence interval [CI], 0.70 to 1.18; P=0.47) in the SILCAAT study and 0.94 (95% CI, 0.75 to 1.16; P=0.55) in ESPRIT. The hazard ratios for death from any cause and for grade 4 clinical events were 1.06 (P=0.73) and 1.10 (P=0.35), respectively, in the SILCAAT study and 0.90 (P=0.42) and 1.23 (P=0.003), respectively, in ESPRIT. CONCLUSIONS: Despite a substantial and sustained increase in the CD4+ cell count, as compared with antiretroviral therapy alone, interleukin-2 plus antiretroviral therapy yielded no clinical benefit in either study. (ClinicalTrials.gov numbers, NCT00004978 [ESPRIT] and NCT00013611 [SILCAAT study].)


Assuntos
Antirretrovirais/uso terapêutico , Infecções por HIV/tratamento farmacológico , Interleucina-2/uso terapêutico , Infecções Oportunistas Relacionadas com a AIDS/epidemiologia , Adulto , Terapia Antirretroviral de Alta Atividade , Contagem de Linfócito CD4 , Quimioterapia Combinada , Feminino , Seguimentos , HIV/genética , HIV/isolamento & purificação , Infecções por HIV/mortalidade , Infecções por HIV/virologia , Humanos , Injeções Subcutâneas , Interleucina-2/administração & dosagem , Interleucina-2/análogos & derivados , Masculino , RNA Viral/sangue , Proteínas Recombinantes/administração & dosagem , Proteínas Recombinantes/uso terapêutico
14.
Acta Virol ; 56(4): 305-14, 2012.
Artigo em Inglês | MEDLINE | ID: mdl-23237086

RESUMO

Cassava mosaic disease (CMV), caused by one or a combination of cassava mosaic geminiviruses, is ranked among the most important constraints to profitable and efficient production of cassava. Effective control measures require in-depth knowledge of the viral causative agent. Using rolling-circle amplification and unique enzymes, the full genome of two species of cassava mosaic geminivirus isolated from infected cassava plants in Ghana were cloned into pCambia 1300 and pET-28b. The sequences of the genome were determined on an ABI sequencer and a pairwise comparison was performed with other cassava-infecting geminiviruses from different countries. It was revealed that cassava grown in Ghana is attacked by two species of geminivirus in either single or mixed infections. These are the African cassava mosaic virus (ACMV) and the East African cassava mosaic virus (EACMV)-like, with high sequence similarity of 94% and 80%, respectively, between the DNA-A and DNA-B components of each virus, and 66% and 41% similarity of the common region (CR) (for A and B accordingly). The DNA-A of ACMV and EACMV-like contained 2781 and 2800 nucleotides, respectively, while their DNA-B components had 2725 and 2734 nucleotides, respectively. ACMV DNA-A was over 97% similar to those of other ACMVs from the continent. In contrast, EACMV-like DNA-A was over 98% similar to the isolates from Cameroon and other West African countries, and less than 88% similar to other EACMV species. Thus ACMV and EACMV-like were named African cassava mosaic virus-Ghana and East African cassava mosaic Cameroon virus-Ghana. Computer analysis revealed that their genome arrangement follows the typical old world bipartite begomovirus genome. The association of these two species and their interaction might account for the severe symptoms observed on infected plants in the field and in the greenhouse.


Assuntos
Begomovirus/genética , Begomovirus/isolamento & purificação , Genoma Viral , Manihot/virologia , Doenças das Plantas/virologia , Sequência de Bases , Begomovirus/classificação , Gana , Dados de Sequência Molecular , Filogenia , Análise de Sequência de DNA
15.
Nat Commun ; 13(1): 7856, 2022 12 21.
Artigo em Inglês | MEDLINE | ID: mdl-36543800

RESUMO

Silk is a unique, remarkably strong biomaterial made of simple protein building blocks. To date, no synthetic method has come close to reproducing the properties of natural silk, due to the complexity and insufficient understanding of the mechanism of the silk fiber formation. Here, we use a combination of bulk analytical techniques and nanoscale analytical methods, including nano-infrared spectroscopy coupled with atomic force microscopy, to probe the structural characteristics directly, transitions, and evolution of the associated mechanical properties of silk protein species corresponding to the supramolecular phase states inside the silkworm's silk gland. We found that the key step in silk-fiber production is the formation of nanoscale compartments that guide the structural transition of proteins from their native fold into crystalline ß-sheets. Remarkably, this process is reversible. Such reversibility enables the remodeling of the final mechanical characteristics of silk materials. These results open a new route for tailoring silk processing for a wide range of new material formats by controlling the structural transitions and self-assembly of the silk protein's supramolecular phases.


Assuntos
Fibroínas , Seda , Seda/química , Materiais Biocompatíveis/química , Microscopia de Força Atômica , Espectrofotometria Infravermelho , Fibroínas/química
16.
Pediatr Allergy Immunol ; 22(2): 172-7, 2011 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-20536784

RESUMO

Little is known about the courses, causes, and clinical features of anaphylaxis in children outside the USA and Europe. Our objective was to evaluate the events of anaphylaxis in children admitted to the Schneider Children's Medical Center of Israel, a major tertiary facility, over a 12-year period. Ninety-two children with anaphylaxis (50 boys, 42 girls) aged 14 days to 18 yr (mean, 7.4 yr) were hospitalized during the study period. The event occurred at home in 52 children (56%), in a medical institution in 24 (26%), outdoors in 13 (15%), at school in 2 (2%), and in an unspecified location in 1 (1%). The main causes were foods (43%), mainly milk and nuts, medications (22%), and hymenoptera venom (11%); in five children, anaphylaxis occurred during general anesthesia, and in 5, the causative agent could not be determined. Food-induced anaphylaxis tended to occur in younger children. Forty-eight children (52%) had a history of atopy (mainly asthma). Hospital treatment consisted of corticosteroids (85%), antihistamines (75%), epinephrine (72%), and ß2 agonists (42%). Seven patients were admitted to intensive care units. There were no fatalities. EpiPen was used by only one of the 16 patients with more than one episode of anaphylaxis, indicating that patient and parent education in the application of the EpiPen needs to be improved.


Assuntos
Anafilaxia/epidemiologia , Anafilaxia/etiologia , Adolescente , Corticosteroides/uso terapêutico , Agonistas de Receptores Adrenérgicos beta 2/uso terapêutico , Anafilaxia/imunologia , Anafilaxia/patologia , Anafilaxia/prevenção & controle , Anestesia/efeitos adversos , Venenos de Artrópodes/efeitos adversos , Venenos de Artrópodes/imunologia , Asma/complicações , Asma/imunologia , Criança , Criança Hospitalizada , Pré-Escolar , Efeitos Colaterais e Reações Adversas Relacionados a Medicamentos , Epinefrina/uso terapêutico , Feminino , Hipersensibilidade Alimentar/complicações , Hipersensibilidade Alimentar/imunologia , Antagonistas dos Receptores Histamínicos/uso terapêutico , Humanos , Lactente , Recém-Nascido , Israel/epidemiologia , Masculino , Estudos Retrospectivos
17.
Curr Opin Struct Biol ; 18(1): 60-6, 2008 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-18160276

RESUMO

Human immunodeficiency virus type 1 (HIV-1) protease (PR) plays an essential role in the life cycle of the virus. Consequently, its inhibition can control acquired immunodeficiency syndrome (AIDS). Any pharmacological treatment targeting the active site of the protease is known to generate escape mutants. On the other hand, if a drug targets a site crucial for the correct folding of the protease, mutations affecting this region would denaturate the protein and thus will not be expressed. We review the progress in our understanding of the folding of the protease, which has been instrumental in the design of a (non-conventional) folding inhibitor. The transferability of these results to other proteins testify to the universality of the folding-inhibition scenario for the design of leads of drugs which are unlikely to generate resistance.


Assuntos
Inibidores da Protease de HIV/química , Protease de HIV/química , Animais , Desenho de Fármacos , Farmacorresistência Viral , Protease de HIV/metabolismo , Inibidores da Protease de HIV/farmacologia , Humanos , Cinética , Modelos Moleculares , Conformação Proteica , Dobramento de Proteína , Estrutura Terciária de Proteína
18.
Nat Med ; 3(10): 1133-6, 1997 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-9334726

RESUMO

Multiple sclerosis (MS) is a T cell-mediated autoimmune demyelinating disease, which may be initiated by a virus infection. Theiler's murine encephalomyelitis virus (TMEV), a natural mouse pathogen, is a picornavirus that induces a chronic, CD4+ T cell-mediated demyelinating disease with a clinical course and histopathology similar to that of chronic progressive MS (ref. 3). Demyelination in TMEV-infected mice is initiated by a mononuclear inflammatory response mediated by virus-specific CD4+ T cells targeting virus, which chronically persists in the CNS (ref. 4-6). We show that beginning 3-4 weeks after disease onset, T-cell responses to multiple myelin autoepitopes arise in an ordered progression and may play a pathologic role in chronic disease. Kinetic and functional studies show that T-cell responses to the immunodominant myelin proteolipid protein epitope (PLP139-151) did not arise because of cross-reactivity between TMEV and self epitopes (that is, molecular mimicry), but because of de novo priming of self-reactive T cells to sequestered autoantigens released secondary to virus-specific T cell-mediated demyelination (that is, epitope spreading). Epitope spreading is an important alternate mechanism to explain the etiology of virus-induced organ-specific autoimmune diseases.


Assuntos
Autoimunidade , Doenças Desmielinizantes/imunologia , Epitopos/imunologia , Proteínas da Mielina/imunologia , Proteína Proteolipídica de Mielina/imunologia , Poliomielite/imunologia , Linfócitos T/imunologia , Theilovirus , Sequência de Aminoácidos , Animais , Linfócitos T CD4-Positivos/imunologia , Reações Cruzadas , Feminino , Inflamação , Cinética , Camundongos , Camundongos Endogâmicos , Dados de Sequência Molecular , Proteínas da Mielina/química , Proteína Proteolipídica de Mielina/química , Poliomielite/fisiopatologia , Tolerância a Antígenos Próprios
19.
J Exp Med ; 181(3): 839-44, 1995 Mar 01.
Artigo em Inglês | MEDLINE | ID: mdl-7869046

RESUMO

Interleukin-10 (IL-10) is produced at a high level by B lymphocytes and monocytes of patients with systemic lupus erythematosus (SLE). In the present work, we analyzed whether this increased production of IL-10 contributed to the abnormal production of immunoglobulins (Ig) and of autoantibodies in SLE. The role of IL-10 was compared with that of IL-6, another cytokine suspected to play a role in these abnormalities. The spontaneous in vitro production of IgM, IgG, and IgA by peripheral blood mononuclear cells from SLE patients was weakly increased by recombinant IL (rIL)-6, but strongly by rIL-10. This production was not significantly affected by an anti-IL-6 mAb but was decreased by an anti-IL-10 mAb. We then tested the in vivo effect of these antibodies in severe combined immunodeficiency mice injected with PBMC from SLE patients. The anti-IL-6 mAb did not significantly affect the serum concentration of total human IgG and of anti-double-stranded DNA IgG in the mice. In contrast, the anti-IL-10 mAb strongly inhibited the production of autoantibodies, and, to a lesser extent, that of total human IgG. These results indicate that the Ig production by SLE B lymphocytes is largely IL-10 dependent, and that the increased production of IL-10 by SLE B lymphocytes and monocytes may represent a critical mechanism in the emergence of the autoimmune manifestations of the disease.


Assuntos
Autoanticorpos/biossíntese , Linfócitos B/imunologia , Interleucina-10/fisiologia , Lúpus Eritematoso Sistêmico/imunologia , Adulto , Animais , Anticorpos Monoclonais/imunologia , Células Cultivadas , Feminino , Humanos , Imunoglobulinas/biossíntese , Interleucina-10/farmacologia , Interleucina-6/farmacologia , Interleucina-6/fisiologia , Camundongos , Camundongos SCID , Pessoa de Meia-Idade , Proteínas Recombinantes/farmacologia
20.
Ann Rheum Dis ; 69(1): 61-4, 2010 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-19155235

RESUMO

OBJECTIVE: To update the follow-up of the Euro-Lupus Nephritis Trial (ELNT), a randomised prospective trial comparing low-dose (LD) and high-dose (HD) intravenous (IV) cyclophosphamide (CY) followed by azathioprine (AZA) as treatment for proliferative lupus nephritis. PATIENTS AND METHODS: Data for survival and kidney function were prospectively collected during a 10-year period for the 90 patients randomised in the ELNT, except in 6 lost to follow-up. RESULTS: Death, sustained doubling of serum creatinine and end-stage renal disease rates did not differ between the LD and HD group (5/44 (11%) vs 2/46 (4%), 6/44 (14%) vs 5/46 (11%) and 2/44 (5%) vs 4/46 (9%), respectively) nor did mean serum creatinine, 24 h proteinuria and damage score at last follow-up. Most patients in both groups were still treated with glucocorticoids, other immunosuppressant agents and blood pressure lowering drugs. After 10 years of follow-up, the positive predictive value for a good outcome of an early drop in proteinuria in response to initial immunosuppressive therapy was confirmed. CONCLUSION: The data confirm that a LD IVCY regimen followed by AZA-the "Euro-Lupus regimen"-achieves good clinical results in the very long term.


Assuntos
Ciclofosfamida/administração & dosagem , Imunossupressores/administração & dosagem , Nefrite Lúpica/tratamento farmacológico , Adolescente , Adulto , Azatioprina/uso terapêutico , Ciclofosfamida/uso terapêutico , Relação Dose-Resposta a Droga , Quimioterapia Combinada , Métodos Epidemiológicos , Feminino , Humanos , Imunossupressores/uso terapêutico , Injeções Intravenosas , Testes de Função Renal , Nefrite Lúpica/fisiopatologia , Masculino , Pessoa de Meia-Idade , Proteinúria/tratamento farmacológico , Resultado do Tratamento , Adulto Jovem
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA