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1.
BMC Med ; 22(1): 170, 2024 Apr 23.
Artigo em Inglês | MEDLINE | ID: mdl-38649867

RESUMO

BACKGROUND: The stalling global progress in malaria control highlights the need for novel tools for malaria elimination, including transmission-blocking vaccines. Transmission-blocking vaccines aim to induce human antibodies that block parasite development in the mosquito and mosquitoes becoming infectious. The Pfs48/45 protein is a leading Plasmodium falciparum transmission-blocking vaccine candidate. The R0.6C fusion protein, consisting of Pfs48/45 domain 3 (6C) and the N-terminal region of P. falciparum glutamate-rich protein (R0), has previously been produced in Lactococcus lactis and elicited functional antibodies in rodents. Here, we assess the safety and transmission-reducing efficacy of R0.6C adsorbed to aluminium hydroxide with and without Matrix-M™ adjuvant in humans. METHODS: In this first-in-human, open-label clinical trial, malaria-naïve adults, aged 18-55 years, were recruited at the Radboudumc in Nijmegen, the Netherlands. Participants received four intramuscular vaccinations on days 0, 28, 56 and 168 with either 30 µg or 100 µg of R0.6C and were randomised for the allocation of one of the two different adjuvant combinations: aluminium hydroxide alone, or aluminium hydroxide combined with Matrix-M1™ adjuvant. Adverse events were recorded from inclusion until 84 days after the fourth vaccination. Anti-R0.6C and anti-6C IgG titres were measured by enzyme-linked immunosorbent assay. Transmission-reducing activity of participants' serum and purified vaccine-specific immunoglobulin G was assessed by standard membrane feeding assays using laboratory-reared Anopheles stephensi mosquitoes and cultured P. falciparum gametocytes. RESULTS: Thirty-one participants completed four vaccinations and were included in the analysis. Administration of all doses was safe and well-tolerated, with one related grade 3 adverse event (transient fever) and no serious adverse events occurring. Anti-R0.6C and anti-6C IgG titres were similar between the 30 and 100 µg R0.6C arms, but higher in Matrix-M1™ arms. Neat participant sera did not induce significant transmission-reducing activity in mosquito feeding experiments, but concentrated vaccine-specific IgGs purified from sera collected two weeks after the fourth vaccination achieved up to 99% transmission-reducing activity. CONCLUSIONS: R0.6C/aluminium hydroxide with or without Matrix-M1™ is safe, immunogenic and induces functional Pfs48/45-specific transmission-blocking antibodies, albeit at insufficient serum concentrations to result in transmission reduction by neat serum. Future work should focus on identifying alternative vaccine formulations or regimens that enhance functional antibody responses. TRIAL REGISTRATION: The trial is registered with ClinicalTrials.gov under identifier NCT04862416.


Assuntos
Vacinas Antimaláricas , Malária Falciparum , Glicoproteínas de Membrana , Plasmodium falciparum , Proteínas de Protozoários , Adolescente , Adulto , Animais , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Adulto Jovem , Adjuvantes Imunológicos/administração & dosagem , Hidróxido de Alumínio/administração & dosagem , Anticorpos Antiprotozoários , Vacinas Antimaláricas/imunologia , Vacinas Antimaláricas/administração & dosagem , Malária Falciparum/prevenção & controle , Malária Falciparum/transmissão , Malária Falciparum/imunologia , Países Baixos , Plasmodium falciparum/imunologia , Proteínas de Protozoários/imunologia
2.
Nature ; 604(7905): 280-286, 2022 04.
Artigo em Inglês | MEDLINE | ID: mdl-35418631

RESUMO

Multijunction solar cells can overcome the fundamental efficiency limits of single-junction devices. The bandgap tunability of metal halide perovskite solar cells renders them attractive for multijunction architectures1. Combinations with silicon and copper indium gallium selenide (CIGS), as well as all-perovskite tandem cells, have been reported2-5. Meanwhile, narrow-gap non-fullerene acceptors have unlocked skyrocketing efficiencies for organic solar cells6,7. Organic and perovskite semiconductors are an attractive combination, sharing similar processing technologies. Currently, perovskite-organic tandems show subpar efficiencies and are limited by the low open-circuit voltage (Voc) of wide-gap perovskite cells8 and losses introduced by the interconnect between the subcells9,10. Here we demonstrate perovskite-organic tandem cells with an efficiency of 24.0 per cent (certified 23.1 per cent) and a high Voc of 2.15 volts. Optimized charge extraction layers afford perovskite subcells with an outstanding combination of high Voc and fill factor. The organic subcells provide a high external quantum efficiency in the near-infrared and, in contrast to paradigmatic concerns about limited photostability of non-fullerene cells11, show an outstanding operational stability if excitons are predominantly generated on the non-fullerene acceptor, which is the case in our tandems. The subcells are connected by an ultrathin (approximately 1.5 nanometres) metal-like indium oxide layer with unprecedented low optical/electrical losses. This work sets a milestone for perovskite-organic tandems, which outperform the best p-i-n perovskite single junctions12 and are on a par with perovskite-CIGS and all-perovskite multijunctions13.


Assuntos
Compostos de Cálcio , Índio , Cobre , Óxidos , Titânio
3.
Parasit Vectors ; 10(1): 395, 2017 Aug 23.
Artigo em Inglês | MEDLINE | ID: mdl-28835262

RESUMO

BACKGROUND: Plasmodium falciparum genetic diversity and multiplicity of infection (MOI) are parasite features that have been suggested to influence the acquisition of protective immunity against malaria. This study sought to assess the relationship between MOI and parasite density (PD) in malaria patients living in the Central Region of Ghana and to determine whether naturally occurring antibody levels against P. falciparum GLURP (PF3D7_1035300) and MSP3 (PF3D7_1035400) antigens are associated with decreased parasite load. METHODS: Dried filter paper blood blots were obtained from children and adults diagnosed with uncomplicated P. falciparum malaria. Microscopy was used to estimate P. falciparum parasite density and polymerase chain reaction (PCR) amplification of the polymorphic regions of msp1 (PF3D7_0930300) and msp2 (PF3D7_0206800) was used for parasite genotyping and MOI determination. ELISA was used to measure the serum IgG concentration of R0 fragment of GLURP (GLURP(R0)) and MSP3 antibodies. RESULTS: All 115 samples were positive for P. falciparum by PCR using either the msp1 or msp2 genotyping primer sets. The most prevalent msp1 and msp2 alleles were KI and 3D7, respectively. The geometric mean (GM) for MOI determined by both msp1 and msp2 genotyping was 1.3 for the entire population and was generally higher in children than in adults. Seropositivity was estimated at 67 and 63% for GLURP(R0) and MSP3 antibodies, respectively, and antibody titers were negatively correlated with parasite density. CONCLUSIONS: The negative correlation between naturally occurring GLURP(R0) and MSP3 antibody levels and parasite density observed in this study suggest that augmenting the antibody response with the GMZ2 vaccine could enhance protection in the Central Region of Ghana.


Assuntos
Antígenos de Protozoários/imunologia , Malária Falciparum/imunologia , Malária Falciparum/parasitologia , Carga Parasitária , Plasmodium falciparum/imunologia , Plasmodium falciparum/fisiologia , Proteínas de Protozoários/imunologia , Adolescente , Adulto , Animais , Antígenos de Protozoários/genética , Criança , Pré-Escolar , Teste em Amostras de Sangue Seco , Ensaio de Imunoadsorção Enzimática , Feminino , Variação Genética , Genótipo , Gana/epidemiologia , Humanos , Imunoglobulina G/sangue , Lactente , Vacinas Antimaláricas/imunologia , Malária Falciparum/epidemiologia , Masculino , Proteína 1 de Superfície de Merozoito/genética , Plasmodium falciparum/genética , Reação em Cadeia da Polimerase , Proteínas de Protozoários/genética , Adulto Jovem
4.
Arch Dermatol Res ; 306(10): 903-14, 2014 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-25362540

RESUMO

Annexin A1 deregulation is often associated with cancer. Indeed we have shown that annexin A1 is overexpressed in melanoma and promotes metastases by formyl peptide receptor stimulation and MMP2 expression. Here, we demonstrated in different melanoma cell lines that annexin A1-MMP2 induction is mediated by MAPK and STAT3 pathways. To decipher endogenous annexin A1 action mode, we showed that annexin A1 is externalized in A375 cells and cleaved by a membrane-associated serine protease, allowing the release of a pro-invasive annexin A1 peptide in the extra cellular environment. Finally, a biochemical and proteomic approach allowed to enrich eight out of 12 members of the annexin family and to identify an original annexin A1 cleavage site localized between Ser(28) and Lys(29). Altogether, these data identify signaling pathways involved in annexin A1 pro-invasive role and suggest that externalized full-length annexin A1 interacts with formyl peptide receptors in a juxtacrine manner while ANXA 2-28 release allows autocrine and paracrine interaction.


Assuntos
Anexina A1/metabolismo , Melanoma/metabolismo , Fragmentos de Peptídeos/metabolismo , Neoplasias Cutâneas/metabolismo , Animais , Comunicação Autócrina , Linhagem Celular Tumoral , Membrana Celular/enzimologia , Humanos , Masculino , Metaloproteinase 2 da Matriz/metabolismo , Melanoma/enzimologia , Melanoma/patologia , Camundongos Nus , Proteínas Quinases Ativadas por Mitógeno/metabolismo , Invasividade Neoplásica , Comunicação Parácrina , Estrutura Terciária de Proteína , Receptores de Formil Peptídeo/metabolismo , Fator de Transcrição STAT3/metabolismo , Serina Proteases/metabolismo , Transdução de Sinais , Neoplasias Cutâneas/enzimologia , Neoplasias Cutâneas/patologia
5.
Scand J Immunol ; 75(6): 606-13, 2012 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-22268665

RESUMO

FcγRIIa is known to be polymorphic; and certain variants are associated with different susceptibilities to malaria. Studies involving the Fulani ethnic group reported an ethnic difference in FcγRIIa-R131H genotype frequencies between the Fulani and other sympatric groups. No previous studies have addressed these questions in Burkina Faso. This study aimed to assess the influence of FcγRIIa-R131H polymorphism on anti-falciparum malaria IgG and IgG subclass responses in the Fulani and the Mossi ethnic groups living in Burkina Faso. Healthy adults more than 20 years old belonging to the Mossi or the Fulani ethnic groups were enrolled for the assessment of selected parasitological, immunological and genetic variables in relation to their susceptibility to malaria. The prevalence of the Plasmodium falciparum infection frequency was relatively low in the Fulani ethnic group compared to the Mossi ethnic group. For all tested antigens, the Fulani had higher antibody levels than the Mossi group. In both ethnic groups, a similar distribution of FcγRIIa R131H polymorphism was found. Individuals with the R allele of FcγRIIa had higher antibody levels than those with the H allele. This study confirmed that malaria infection affected less the Fulani group than the Mossi group. FcγRIIa-R131H allele distribution is similar in both ethnic groups, and higher antibody levels are associated with the FcγRIIa R allele compared to the H allele.


Assuntos
Predisposição Genética para Doença/genética , Imunoglobulina G/imunologia , Malária Falciparum/etnologia , Malária Falciparum/genética , Polimorfismo de Nucleotídeo Único , Receptores de IgG/genética , Adulto , Burkina Faso , Ensaio de Imunoadsorção Enzimática , Feminino , Genótipo , Humanos , Imunoglobulina G/genética , Malária Falciparum/imunologia , Masculino , Reação em Cadeia da Polimerase , Polimorfismo de Nucleotídeo Único/genética
6.
Phys Chem Chem Phys ; 13(42): 18781-8, 2011 Nov 14.
Artigo em Inglês | MEDLINE | ID: mdl-21789302

RESUMO

The preparation of an artificial superatom consisting of a positive charge inside a superfluid helium nanodroplet and an electron in an orbital surrounding the droplet is of fundamental interest and represents an experimental challenge. In this work, nanodroplets of several thousand helium atoms are doped with single caesium (Cs) atoms. While on the droplet, the Cs valence electron is excited in two steps through an intermediate state into nS, nP, and nD states. The excitation is monitored by laser induced fluorescence or, for high principal quantum numbers, by resonant three-photon-ionization. On-droplet Rydberg excitations are resolved up to about n = 20. The energies are compared with those of free Cs atom Rydberg states and quantum defects as well as the on-droplet ionization threshold are derived.

7.
Lab Anim ; 43(1): 96-101, 2009 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-19015175

RESUMO

The aim of this study was to find the fastest, easiest and safest method of achieving orotracheal intubation for general anaesthesia in laboratory pigs. Twenty-one Yorkshire x Landrace crossbreed male castrated pigs (32.9 +/- 4.8 kg) were investigated. Dorsal and ventral recumbency are the alternatives most frequently described for animal positioning during intubation procedures. Based on standardized induction of general anaesthesia using pentobarbital and remifentanil, the dorsoventral and ventrodorsal positions were compared with regard to the time needed, changes in oxygenation and circulatory response. Positioning was found to be crucial for fast orotracheal intubation. The time required for safe intubation is significantly shorter with the ventrodorsal position (17.3 s) in comparison with the dorsoventral position (58.4 s; P < 0.001). Hypoxia did not occur in either group. A significant drop in systolic blood pressure was observed in both groups. Diastolic and mean arterial pressures were not influenced by intubation. A significant increase in heart rate was observed in pigs intubated in ventral recumbency, but not after intubation in the dorsal position. Preoxygenation before intubation is vitally important for preventing hypoxia. With regard to clinical practice, the haemodynamic changes observed in this investigation do not appear to be relevant, as the mean arterial pressure was not altered and heart rates only increased moderately. It may be concluded that the ventrodorsal position can be recommended for orotracheal intubation in pigs as the first choice for providing a smooth and fast airway.


Assuntos
Anestesia Endotraqueal/veterinária , Intubação Intratraqueal/veterinária , Ciência dos Animais de Laboratório/métodos , Suínos/cirurgia , Anestesia Endotraqueal/métodos , Animais , Intubação Intratraqueal/métodos , Laringoscopia/métodos , Laringoscopia/veterinária , Fatores de Tempo
8.
Trop Med Int Health ; 13(2): 229-37, 2008 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-18304269

RESUMO

OBJECTIVES: To examine whether the humoural response to malaria vaccine candidate antigens, Plasmodium falciparum [circumsporozoite repetitive sequence (NANP)(5) GLURP fragments (R0 and R2) and MSP3] varies with the level of malaria transmission and to determine whether the antibodies (IgG) present at the beginning of the malaria transmission season protect against clinical malaria. METHODS: Cross-sectional surveys were conducted to measure antibody response before, at the peak and at the end of the transmission season in children aged 6 months to 10 years in two villages with different levels of malaria transmission. A cohort study was performed to estimate the incidence of clinical malaria. RESULTS: Antibodies to these antigens showed different seasonal patterns. IgG concentrations to any of the four antigens were higher in the village with high entomological inoculation rate. Multivariate analysis of combined data from the two villages indicated that children who were classified as responders to the selected antigens were at lower risk of clinical malaria than children classified as non-responders [(NANP)(5) (incidence rate ratio (IRR) = 0.65, 95% CI: 0.46-0.92; P = 0.016), R0 (IRR = 0.69, 95% CI: 0.48-0.97; P = 0.032), R2 (IRR = 0.73, 95% CI: 0.50-1.06; P = 0.09), MSP3 (IRR = 0.52, 95% CI: 0.32-0.85; P = 0.009)]. Fitting a model with all four antibody responses showed that MSP3 looked the best malaria vaccine candidate (IRR = 0.63; 95% CI: 0.38-1.05; P = 0.08). CONCLUSION: Antibody levels to the four antigens are affected by the intensity of malaria transmission and associated with protection against clinical malaria. It is worthwhile investing in the development of these antigens as potential malaria vaccine candidates.


Assuntos
Anticorpos Antiprotozoários/imunologia , Antígenos de Protozoários/imunologia , Vacinas Antimaláricas/imunologia , Malária Falciparum/prevenção & controle , Malária Falciparum/transmissão , Animais , Anticorpos Antiprotozoários/sangue , Burkina Faso , Criança , Pré-Escolar , Estudos Transversais , Humanos , Imunoglobulina G/sangue , Imunoglobulina G/imunologia , Lactente , Malária Falciparum/imunologia , Malária Falciparum/parasitologia , Plasmodium falciparum/imunologia , Proteínas de Protozoários/imunologia , Estações do Ano
9.
Parasite Immunol ; 26(6-7): 265-72, 2004.
Artigo em Inglês | MEDLINE | ID: mdl-15541030

RESUMO

A longitudinal study was undertaken in Burkina Faso among 293 children aged 6 months to 9 years in order to determine the correlation between an antibody response to several individual malarial antigens and malarial infection. It was found that the presence of a positive antibody response at the beginning of the rainy season to three long synthetic peptides corresponding to Plasmodium falciparum Exp-1 101-162, MSP-3 154-249 and GLURP 801-920 but not to CSP 274-375 correlated with a statistically significant decrease in malarial infection during the ongoing transmission season. The simultaneous presence of an antibody response to more than one antigen is indicative of a lower frequency of malarial infection. This gives scientific credibility to the notion that a successful malaria vaccine should contain multiple antigens.


Assuntos
Anticorpos Antiprotozoários/sangue , Antígenos de Protozoários/imunologia , Malária Falciparum/imunologia , Oligopeptídeos/imunologia , Plasmodium falciparum/imunologia , Proteínas de Protozoários/imunologia , Animais , Burkina Faso , Criança , Pré-Escolar , Estudos Transversais , Ensaio de Imunoadsorção Enzimática , Feminino , Humanos , Imunoglobulina G/sangue , Lactente , Estudos Longitudinais , Malária Falciparum/prevenção & controle , Masculino
10.
Scand J Immunol ; 59(4): 363-72, 2004 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-15049780

RESUMO

The immunogenicity and protective efficacy of various antigen-adjuvant formulations derived either from the merozoite-surface protein-3 (MSP-3) or the glutamate-rich protein (GLURP) of Plasmodium falciparum were evaluated in Saimiri sciureus monkeys. These proteins were selected for immunogenicity studies based primarily on their capacity of inducing an antibody-dependent cellular inhibition effect on parasite growth. Some of the S. sciureus monkeys immunized with MSP-3(212-380)-AS02 or GLURP(27-500)-alum were able to fully or partially control parasitaemia upon an experimental P. falciparum [Falciparum Uganda Palo Alto (FUP-SP) strain] blood-stage infection, and this protection was related to the prechallenge antibody titres induced. The data are indicative that MSP-3 and GLURP can induce protective immunity against an experimental P. falciparum infection using adjuvants that are acceptable for human use and this should trigger further studies with those new antigens.


Assuntos
Anticorpos/sangue , Antígenos de Protozoários/farmacologia , Vacinas Antimaláricas/farmacologia , Malária Falciparum/prevenção & controle , Plasmodium falciparum/imunologia , Proteínas de Protozoários/farmacologia , Animais , Anticorpos/imunologia , Antígenos de Protozoários/administração & dosagem , Antígenos de Protozoários/imunologia , Imunofluorescência , Memória Imunológica/efeitos dos fármacos , Memória Imunológica/imunologia , Vacinas Antimaláricas/administração & dosagem , Vacinas Antimaláricas/imunologia , Peptídeos/administração & dosagem , Peptídeos/imunologia , Peptídeos/farmacologia , Proteínas de Protozoários/administração & dosagem , Proteínas de Protozoários/imunologia , Saimiri
11.
Acta Trop ; 88(1): 17-25, 2003 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-12943972

RESUMO

Insecticide treated materials (ITM) are considered a useful malaria control measure for endemic countries, but whether they also delay the acquisition of immunity to malaria remains unclear. This study investigates plasma antibody levels in 160 children aged 3-6 years from five villages protected by insecticide treated curtains (ITC) over 6 years and in 184 children of the same age group from five villages in the same area never covered by ITC. The antigens to which antibodies were investigated were: the Plasmodium falciparum circumsporozoite protein (CSP) repetitive sequence (NANP)5; the C-terminal domain of the P. falciparum exported protein 1 (Cter-PfExp1); three fragments of the glutamate rich protein (GLURP), referred to as R0, R1 and R2; the merozoite surface protein 3 (MSP3). The level of antibodies was lower in children from the ITC area than in children from the non-ITC area for (NANP)5, R0, R2 and MSP3. Prevalence and intensity of P. falciparum infection were similar in the two groups of children. These findings suggest that reducing the level of malaria transmission over a long period may affect the level of antibodies in children to both sporozoite and blood stage malaria antigens.


Assuntos
Antígenos de Protozoários/sangue , Malária Falciparum/imunologia , Controle de Mosquitos , Plasmodium falciparum/imunologia , Animais , Formação de Anticorpos , Burkina Faso/epidemiologia , Criança , Pré-Escolar , Ensaio de Imunoadsorção Enzimática , Feminino , Humanos , Malária Falciparum/epidemiologia , Malária Falciparum/prevenção & controle , Masculino , Prevalência
12.
Intensive Care Med ; 29(6): 995-1002, 2003 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-12739012

RESUMO

OBJECTIVE: To investigate the effects of combined selective inducible nitric oxide synthase (iNOS) inhibition using 1400 W with nicotinamide (NAD) as a PARS-inhibitor on hepato-splanchnic hemodynamics, O(2) kinetics, and energy metabolism during hyperdynamic porcine endotoxemia. DESIGN: Prospective, randomized, controlled, interventional experiment. SETTING: Animal research laboratory. SUBJECTS: Seventeen domestic pigs. INTERVENTIONS: After 12 h of continuous i.v. endotoxin (LPS) infusion 17 pigs received either no drug (CON, n=9) or 1400 W, titrated to maintain mean arterial pressure (MAP) at pre-endotoxin level, plus 10 mg.kg.h NAD ( n=8;). Measurements were obtained before, 12 h, 18 h, and 24 h after starting LPS infusion. MEASUREMENTS AND RESULTS: In addition to systemic and pulmonary hemodynamics and gas exchange, we measured hepatic arterial and portal venous blood flow, liver and portal venous drained viscera O(2) exchange, ileal mucosal-arterial PCO(2) gap, and portal as well as hepatic venous lactate/pyruvate ratios. Expired NO and plasma nitrate levels were assessed as a parameter of NO production. Without affecting cardiac output, therapy maintained MAP and blunted the LPS-induced rise in expired NO levels, attenuated the progressive fall in liver lactate clearance, and blunted the impairment of hepato-splanchnic redox state. The rise of ileal mucosal-arterial PCO(2) gap was not influenced. CONCLUSIONS: Combining selective iNOS inhibition with NAD as a PARS blocker may prevent circulatory failure and attenuate the detrimental consequences of LPS in intestinal and hepatocellular energy metabolism. Given the potential hepatotoxicity of high-dose NAD treatment, more potent PARS blockers with higher selectivity might further enhance the benefit of this therapeutic approach.


Assuntos
Amidinas/uso terapêutico , Benzilaminas/uso terapêutico , Modelos Animais de Doenças , Endotoxemia/tratamento farmacológico , Niacinamida/uso terapêutico , Óxido Nítrico Sintase/antagonistas & inibidores , Inibidores de Poli(ADP-Ribose) Polimerases , Amidinas/farmacologia , Animais , Benzilaminas/farmacologia , Avaliação Pré-Clínica de Medicamentos , Quimioterapia Combinada , Endotoxemia/imunologia , Endotoxemia/metabolismo , Endotoxemia/fisiopatologia , Metabolismo Energético/efeitos dos fármacos , Feminino , Hemodinâmica/efeitos dos fármacos , Mucosa Intestinal/efeitos dos fármacos , Lipopolissacarídeos/efeitos adversos , Circulação Hepática/efeitos dos fármacos , Masculino , Niacinamida/farmacologia , Estudos Prospectivos , Circulação Pulmonar/efeitos dos fármacos , Distribuição Aleatória , Circulação Esplâncnica/efeitos dos fármacos , Suínos , Fatores de Tempo
13.
FEBS Lett ; 515(1-3): 114-8, 2002 Mar 27.
Artigo em Inglês | MEDLINE | ID: mdl-11943205

RESUMO

Potential contamination of animal-derived collagen with pathogens has led to the demand for safe recombinant sources of this complex molecule. In continuation of our previous work [Ruggiero et al. (2000) FEBS Lett. 469, 132-136], here we show that it is possible to produce recombinant hydroxylated homotrimeric collagen in tobacco plants that are co-transformed with a human type I collagen and a chimeric proline-4-hydroxylase (P4H). This is to our knowledge the first time that transient expression in tobacco was used to improve the quality of a recombinant protein produced in plants through co-expression with an animal cell-derived modifying enzyme. We demonstrated the functionality of the new chimeric P4H and thus improved the thermal stability of recombinant collagen I from plants to 37 degrees C.


Assuntos
Agrobacterium tumefaciens/metabolismo , Colágeno Tipo I/genética , Colágeno Tipo I/metabolismo , Nicotiana/genética , Nicotiana/metabolismo , Aminoácidos/análise , Bioensaio , Cromatografia Líquida de Alta Pressão , Dicroísmo Circular , Colágeno Tipo I/isolamento & purificação , Eletroforese em Gel de Poliacrilamida , Expressão Gênica , Humanos , Hidroxilação , Pepsina A/química , Plantas Geneticamente Modificadas , Pró-Colágeno-Prolina Dioxigenase/genética , Pró-Colágeno-Prolina Dioxigenase/metabolismo , Conformação Proteica , Proteínas Recombinantes de Fusão/genética , Proteínas Recombinantes de Fusão/metabolismo , Proteínas Recombinantes/genética , Proteínas Recombinantes/metabolismo , Reação em Cadeia da Polimerase Via Transcriptase Reversa , Temperatura , Nicotiana/química , Transformação Genética
14.
Anal Biochem ; 299(1): 84-91, 2001 Dec 01.
Artigo em Inglês | MEDLINE | ID: mdl-11726188

RESUMO

The orientation of an immobilized antigen is important for recognition by, e.g., an antibody. When noncovalent passive adsorption is used for immobilization, the number of ways that the antigen can attach to the surface is numerous and control of how the antigen orientates on the surface is limited. Covalent immobilization restricts the number of the ways that the antigen can be immobilized to the number of reactive groups on the antigen and, hence, the orientation of the immobilized antigen is more predictable. Peptide antigens were synthesized and purified with protection groups on the lysine and cysteine side chains. These peptides, which have only one good nucleophilic group (the N-terminal alpha-amino group), were immobilized covalently in microtiter plates supplied with tresyl groups on the surface and the protection groups were cleaved off in situ after immobilization. The controlled orientation of these peptides resulted in enhanced recognition by antibodies in general. An enzyme-linked immunosorbent assay for detection of antibodies against a peptide derived from outer surface protein C from Borrelia burgdorferi, found in Lyme borreliosis patients, was established using this strategy. Lyme borreliosis suspect patient sera showed up to a 10-fold increase in the signal when the orientation of the peptide antigen was controlled by the in situ deprotection strategy.


Assuntos
Antígenos de Protozoários , Antígenos de Superfície/imunologia , Proteínas da Membrana Bacteriana Externa/química , Ensaio de Imunoadsorção Enzimática/métodos , Soros Imunes/imunologia , Doença de Lyme/diagnóstico , Peptídeos/química , Proteínas de Protozoários , Anticorpos/imunologia , Borrelia burgdorferi/química , Borrelia burgdorferi/patogenicidade , Humanos , Imunoensaio/métodos , Doença de Lyme/microbiologia , Peptídeos/imunologia , Peptídeos/isolamento & purificação
15.
Shock ; 16(3): 203-10, 2001 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-11531022

RESUMO

We have previously demonstrated that non-selective nitric oxide synthase (NOS) inhibition did not reverse the LPS-induced deterioration of hepato-splanchnic energy status in porcine endotoxic shock. Therefore, this study investigated the effect of selective inducible NOS (iNOS) inhibition using 1400 W on intestinal and liver perfusion, O2 kinetics, and energy metabolism during hyperdynamic porcine endotoxemia. Intravenous E. Coli LPS was continuously infused over 24 h concomitant with fluid resuscitation. After 12 h of endotoxemia, continuous intravenous infusion of 1400 W was started until the end of the experiment and was titrated to maintain mean blood pressure (MAP) at baseline levels. Twelve, 18, and 24 h after starting LPS, we measured hepatic arterial and portal venous blood flow, ileal mucosal-arterial PCO2 gap, portal as well as hepatic venous lactate/pyruvate ratios, and endogenous glucose production rate. Expired NO and plasma nitrate levels were assessed as a measure of NO production. 1400 W decreased LPS-induced increase in expired NO and allowed for the maintenance of MAP without modification of cardiac output. Despite unchanged regional macrocirculation, 1400 W prevented the progressive rise of ileal mucosal-arterial PCO2 gap, significantly improved the LPS-induced impairment of hepato-splanchnic redox state, and blunted the decline in liver lactate clearance. Increased glucose production rate was not influenced. Thus, the selective iNOS inhibition with 1400 W prevented circulatory failure and largely attenuated otherwise progressive LPS-induced deterioration of intestinal and hepatocellular energy metabolism.


Assuntos
Sistema Digestório/metabolismo , Endotoxemia/metabolismo , Fígado/metabolismo , Óxido Nítrico Sintase/antagonistas & inibidores , Óxido Nítrico Sintase/metabolismo , Oxigênio/metabolismo , Amidinas/farmacologia , Animais , Benzilaminas/farmacologia , Sistema Digestório/efeitos dos fármacos , Endotoxemia/tratamento farmacológico , Endotoxemia/fisiopatologia , Metabolismo Energético/efeitos dos fármacos , Inibidores Enzimáticos/farmacologia , Feminino , Hemodinâmica , Mucosa Intestinal/metabolismo , Intestinos/efeitos dos fármacos , Fígado/efeitos dos fármacos , Masculino , Óxido Nítrico Sintase Tipo II , Perfusão , Suínos
16.
J Biol Chem ; 276(47): 43693-8, 2001 Nov 23.
Artigo em Inglês | MEDLINE | ID: mdl-11557756

RESUMO

Human unhydroxylated homotrimeric triple-helical collagen I produced in transgenic plants was used as an experimental model to provide insights into the role of hydroxyproline in molecular folding and fibril formation. By using chemically cross-linked molecules, we show here that the absence of hydroxyproline residues does not prevent correct folding of the recombinant collagen although it markedly slows down the propagation rate compared with bovine fully hydroxylated homotrimeric collagen I. Relatively slow cis-trans-isomerization in the absence of hydroxyproline likely represents the rate-limiting factor in the propagation of the unhydroxylated collagen helix. Because of the lack of hydroxylation, recombinant collagen molecules showed increased flexibility as well as a reduced melting temperature compared with native homotrimers and heterotrimers, whereas the distribution of charged amino acids was unchanged. However, unlike with bovine collagen I, the recombinant collagen did not self-assemble into banded fibrils in physiological ionic strength buffer at 20 degrees C. Striated fibrils were only obtained with low ionic strength buffer. We propose that, under physiological ionic strength conditions, the hydroxyl groups in the native molecule retain water more efficiently thus favoring correct fibril formation. The importance of hydroxyproline in collagen self-assembly suggested by others from the crystal structures of collagen model peptides is thus confirmed experimentally on the entire collagen molecule.


Assuntos
Colágeno Tipo I/metabolismo , Hidroxiprolina/fisiologia , Plantas Geneticamente Modificadas/genética , Dobramento de Proteína , Animais , Bovinos , Colágeno Tipo I/biossíntese , Colágeno Tipo I/química , Colágeno Tipo I/genética , Eletroforese em Gel de Poliacrilamida , Conformação Proteica
17.
Shock ; 16(2): 130-6, 2001 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-11508865

RESUMO

We investigated the effect of mercaptoethylguanidine (MEG, 3 mg kg(-1)h(-1)), a combined selective inducible nitric oxide synthase (iNOS) inhibitor, a peroxynitrite and oxygen free radical scavenger with cyclooxygenase-inhibitor properties on intestinal and hepatic perfusion, O2 exchange, and metabolism during long-term hyperdynamic porcine endotoxemia. MEG was started 12 h after onset of endotoxemia. At baseline and after 12, 18, and 24 h of endotoxemia, hepatic arterial and portal venous blood flow, ileal mucosal-arterial PCO2 gap, portal and hepatic venous lactate/pyruvate ratio, free glutathione (GSH), and 8-isoprostanes were measured. Expired NO and plasma nitrate levels were assessed as well. MEG blunted the endotoxin-induced increase in expired NO and prevented the progressive fall in blood pressure without affecting cardiac output. It attenuated both systemic and regional venous acidosis without influencing the impairment of hepatosplanchnic metabolism nor counteracting the increase in GSH levels. In our model MEG failed to beneficially affect variables of oxidative stress.


Assuntos
Endotoxemia/fisiopatologia , Hemodinâmica/fisiologia , Óxido Nítrico Sintase/antagonistas & inibidores , Ácido Peroxinitroso/antagonistas & inibidores , 6-Cetoprostaglandina F1 alfa/sangue , Animais , Débito Cardíaco , Endotoxemia/sangue , Escherichia coli , Feminino , Glutationa/sangue , Hemoglobinas/metabolismo , Lipopolissacarídeos/toxicidade , Masculino , Óxido Nítrico/análise , Óxido Nítrico Sintase Tipo II , Consumo de Oxigênio , Mecânica Respiratória , Suínos , Tromboxano B2/sangue , Resistência Vascular
18.
Infect Immun ; 69(9): 5223-9, 2001 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-11500389

RESUMO

Antibodies against three long synthetic peptides (LSPs) derived from the glutamate-rich protein (GLURP) of Plasmodium falciparum were analyzed in three cohorts from Liberia, Ghana, and Senegal. Two overlapping LSPs, LR67 and LR68, are derived from the relatively conserved N-terminal nonrepeat region (R0), and the third, LR70, is derived from the R2 repeat region. A high prevalence of antibody responses to each LSP was observed in all three areas of endemic infection. Levels of cytophilic immunoglobulin G (IgG) antibodies against both GLURP regions were significantly correlated with protection from clinical P. falciparum malaria. Protected children from the Ghana cohort possessed predominantly IgG1 antibodies against the nonrepeat epitope and IgG3 antibodies against the repeat epitope. T-cell proliferation responses, studied in the cohort from Senegal, revealed that T-helper-cell epitopes were confined to the nonrepeat region. When used as immunogens, the LR67 and LR68 peptides elicited strong IgG responses in outbred mice and LR67 also induced antibodies in mice of different H-2 haplotypes, confirming the presence of T-helper-cell epitopes in these constructs. Mouse antipeptide antisera recognized parasite proteins as determined by immunofluorescence and immunoblotting. This indicates that synthetic peptides derived from relatively conserved epitopes of GLURP might serve as useful immunogens for vaccination against P. falciparum malaria.


Assuntos
Vacinas Antimaláricas , Malária Falciparum/prevenção & controle , Peptídeos/síntese química , Peptídeos/imunologia , Plasmodium falciparum/imunologia , Proteínas de Protozoários/imunologia , Adolescente , Adulto , Animais , Anticorpos Antiprotozoários/sangue , Antígenos de Protozoários/imunologia , Criança , Pré-Escolar , Feminino , Humanos , Vacinas Antimaláricas/imunologia , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Endogâmicos CBA , Camundongos Endogâmicos DBA , Pessoa de Meia-Idade , Peptídeos/química , Proteínas de Protozoários/química , Proteínas de Protozoários/genética , Linfócitos T/imunologia
19.
Occup Med (Lond) ; 51(4): 278-86, 2001 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-11463873

RESUMO

Musculoskeletal disorders are the leading cause of disability among people between 18 and 64 years of age. Patients with musculoskeletal injuries of the upper extremities are usually evaluated and treated by an individual physician and therapist. However, for patients who have problems, especially after being treated by a hand surgeon and a certified hand therapist, there are few other management options. A multidisciplinary assessment program for patients with chronic upper limb pain has not been described in the literature. As part of The University of Michigan RERC (Rehabilitation Engineering Research Center), the UPPER Program (UPper extremity Protocol Evaluation in Rehabilitation) was developed to evaluate patients who have disabling upper limb musculoskeletal disorders. At the center of the program is a multidisciplinary team composed of a physiatrist (physical medicine and rehabilitation specialist), occupational therapist, physical therapist, exercise physiologist, vocational counselor and pain psychologist. The UPPER Program elements include a pre-evaluation questionnaire, individual team member assessments and a team meeting. It is followed by a patient appointment with the team physician to review the results and recommendations. The essential details of the program are presented in this article so it can be reproduced elsewhere.


Assuntos
Traumatismos do Braço/reabilitação , Transtornos Traumáticos Cumulativos/reabilitação , Equipe de Assistência ao Paciente/organização & administração , Adolescente , Adulto , Protocolos Clínicos , Humanos , Pessoa de Meia-Idade
20.
Intensive Care Med ; 27(4): 757-66, 2001 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-11398705

RESUMO

OBJECTIVE: To investigate whether an increased ileal-mucosal-arterial PCO2 gap (delta PCO2) during hyperdynamic porcine endotoxemia is associated with impaired villus microcirculation. DESIGN: Prospective, randomized, controlled, experimental study. SETTING: Animal research laboratory. ANIMALS: Twenty-two domestic pigs. INTERVENTIONS: After baseline measurements, anesthetized and ventilated pigs received continuous i.v. endotoxin (ETX, n = 12) for 24 h or placebo (SHAM, n = 10). MEASUREMENTS AND RESULTS: Before, as well as 12 and 24 h after, the start of endotoxin or saline portal venous blood flow (QPV, ultrasound flow probe) and lactate/pyruvate ratios (L/P), the ileal-mucosal-arterial delta PCO2 (fiberoptic sensor) and bowel-wall capillary hemoglobin O2 saturation (%Hb-O2-cap, remission spectrophotometry) were assessed together with intravital video records of the ileal-mucosal microcirculation (number of perfused/heterogeneously perfused/unperfused villi) using orthogonal polarization spectral imaging (CYTOSCAN A/R) via an ileostomy. At 12 and 24 h endotoxin infusion, about half of the evaluated villi were heterogeneously or unperfused which was paralleled by a progressive significant increase of the ileal-mucosal-arterial delta PCO2 and portal venous L/P ratios, whereas QPV as well as both the mean %Hb-O2-cap and the %Hb-O2-cap frequency distributions remained unchanged. By contrast, in the SHAM-group, mucosal microcirculation was well-preserved, and none of the other parameters were influenced. CONCLUSIONS: We conclude that an increased ileal-mucosal-arterial delta PCO2 during porcine endotoxemia is related to impaired villus microcirculation. A putative contribution of disturbed cellular oxygen utilization resulting from "cytopathic hypoxia" may also assume importance.


Assuntos
Dióxido de Carbono/sangue , Endotoxemia/sangue , Endotoxemia/fisiopatologia , Infecções por Escherichia coli/sangue , Infecções por Escherichia coli/fisiopatologia , Íleo/irrigação sanguínea , Íleo/fisiopatologia , Mucosa Intestinal/irrigação sanguínea , Mucosa Intestinal/fisiopatologia , Artérias Mesentéricas/fisiopatologia , Animais , Gasometria , Modelos Animais de Doenças , Feminino , Ácido Láctico/sangue , Masculino , Microcirculação/fisiopatologia , Microscopia de Polarização , Veia Porta/fisiopatologia , Estudos Prospectivos , Ácido Pirúvico/sangue , Espectrofotometria , Suínos
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