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1.
Neurobiol Dis ; 199: 106575, 2024 Jun 22.
Artigo em Inglês | MEDLINE | ID: mdl-38914170

RESUMO

CT1812 is a novel, brain penetrant small molecule modulator of the sigma-2 receptor (S2R) that is currently in clinical development for the treatment of Alzheimer's disease (AD). Preclinical and early clinical data show that, through S2R, CT1812 selectively prevents and displaces binding of amyloid beta (Aß) oligomers from neuronal synapses and improves cognitive function in animal models of AD. SHINE is an ongoing phase 2 randomized, double-blind, placebo-controlled clinical trial (COG0201) in participants with mild to moderate AD, designed to assess the safety and efficacy of 6 months of CT1812 treatment. To elucidate the mechanism of action in AD patients and pharmacodynamic biomarkers of CT1812, the present study reports exploratory cerebrospinal fluid (CSF) biomarker data from 18 participants in an interim analysis of the first set of patients in SHINE (part A). Untargeted mass spectrometry-based discovery proteomics detects >2000 proteins in patient CSF and has documented utility in accelerating the identification of novel AD biomarkers reflective of diverse pathophysiologies beyond amyloid and tau, and enabling identification of pharmacodynamic biomarkers in longitudinal interventional trials. We leveraged this technique to analyze CSF samples taken at baseline and after 6 months of CT1812 treatment. Proteome-wide protein levels were detected using tandem mass tag-mass spectrometry (TMT-MS), change from baseline was calculated for each participant, and differential abundance analysis by treatment group was performed. This analysis revealed a set of proteins significantly impacted by CT1812, including pathway engagement biomarkers (i.e., biomarkers tied to S2R biology) and disease modification biomarkers (i.e., biomarkers with altered levels in AD vs. healthy control CSF but normalized by CT1812, and biomarkers correlated with favorable trends in ADAS-Cog11 scores). Brain network mapping, Gene Ontology, and pathway analyses revealed an impact of CT1812 on synapses, lipoprotein and amyloid beta biology, and neuroinflammation. Collectively, the findings highlight the utility of this method in pharmacodynamic biomarker identification and providing mechanistic insights for CT1812, which may facilitate the clinical development of CT1812 and enable appropriate pre-specification of biomarkers in upcoming clinical trials of CT1812.

2.
Clin Exp Immunol ; 174(2): 302-17, 2013 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-23865694

RESUMO

While much is known about tolerogenic dendritic cell effects on forkhead box protein 3 (FoxP3)⁺ regulatory T cells, virtually nothing is known about their effects on another arm of immunoregulation that is mediated by a subpopulation of immunosuppressive B cells. These cells suppress rheumatoid arthritis, lupus and inflammatory bowel disease in mice, and functional defects have been reported in human lupus. We show that co-stimulation-impaired tolerogenic dendritic cells that prevent and reverse type 1 diabetes mellitus induce the proliferation of human immunosuppressive B cells in vitro. We also show that the suppressive properties of these B cells concentrate inside the CD19⁺ CD24⁺ B cell population and more specifically inside the CD19⁺ CD24⁺ CD38⁺ regulatory B cell population. We discovered that B cell conversion into suppressive cells in vitro is partially dependent on dendritic cell production of retinoic acid and also that CD19⁺ CD24⁺ CD38⁺ B regulatory cells express retinoic acid receptors. Taken together, our data suggest a model whereby part of the immunosuppressive properties of human tolerogenic dendritic cells could be mediated by retinoic acid which, in addition to its known role in favouring T cell differentiation to FoxP3⁺ regulatory T cells, acts to convert B cells into immunosuppressive cells.


Assuntos
Linfócitos B Reguladores/imunologia , Células Dendríticas/imunologia , Diabetes Mellitus Tipo 1/imunologia , ADP-Ribosil Ciclase 1/metabolismo , Antígenos CD19/metabolismo , Antígeno CD24/metabolismo , Diferenciação Celular , Proliferação de Células , Células Cultivadas , Fatores de Transcrição Forkhead/metabolismo , Humanos , Tolerância Imunológica , Terapia de Imunossupressão , Linfócitos T Reguladores/imunologia , Tretinoína/imunologia , Tretinoína/metabolismo
3.
Euro Surveill ; 18(24)2013 Jun 13.
Artigo em Inglês | MEDLINE | ID: mdl-23787161

RESUMO

In May 2013, Middle East Respiratory Syndrome Coronavirus (MERS-CoV) infection was diagnosed in an adult male in France with severe respiratory illness, who had travelled to the United Arab Emirates before symptom onset. Contact tracing identified a secondary case in a patient hospitalised in the same hospital room. No other cases of MERS-CoV infection were identified among the index case's 123 contacts, nor among 39 contacts of the secondary case, during the 10-day follow-up period.


Assuntos
Infecções por Coronavirus/epidemiologia , Infecções Respiratórias/epidemiologia , Viagem , Busca de Comunicante , Coronavirus/isolamento & purificação , Infecções por Coronavirus/prevenção & controle , Infecções por Coronavirus/transmissão , Transmissão de Doença Infecciosa/prevenção & controle , Evolução Fatal , França , Humanos , Masculino , Pessoa de Meia-Idade , Infecções Respiratórias/prevenção & controle , Infecções Respiratórias/transmissão , Reação em Cadeia da Polimerase Via Transcriptase Reversa , Emirados Árabes Unidos
4.
Clin Exp Immunol ; 165(1): 60-76, 2011 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-21413939

RESUMO

We have identified a novel interleukin (IL)-7-responsive T cell population [forkhead box P3 (FoxP3(+) ) CD4(+) CD25(+) CD127(+) ] that is comparably functionally suppressive to conventional FoxP3(+) CD4(+) CD25(+) regulatory T cells (T(regs) ). Although IL-2 is the most critical cytokine for thymic development of FoxP3(+) T(regs) , in the periphery other cytokines can be compensatory. CD25(+) CD127(+) T cells treated with IL-7 phenotypically 'matured' into the known 'classical' FoxP3(+) CD4(+) CD25(high) CD127(-) FoxP3(+) T(regs) . In freshly isolated splenocytes, the highest level of FoxP3 expression was found in CD127(+) CD25(+) T cells when compared with CD127(-) CD25(+) or CD127(+) CD25(-) cells. IL-7 treatment of CD4(+) CD25(+) T cells induced an increase in the accumulation of FoxP3 in the nucleus in vitro. IL-7-mediated CD25 cell surface up-regulation was accompanied by a concurrent down-regulation of CD127 in vitro. IL-7 treatment of the CD127(+) CD25(+) FoxP3(+) cells also resulted in up-regulation of cytotoxic T lymphocyte antigen 4 without any changes in CD45RA at the cell surface. Collectively, these data support emerging evidence that FoxP3(+) T cells expressing CD127 are comparably functionally suppressive to CD25(+) CD127(-) FoxP3(+) T cells. This IL-7-sensitive regulation of FoxP3(+) T(reg) phenotype could underlie one peripheral non-IL-2-dependent compensatory mechanism of T(reg) survival and functional activity, particularly for adaptive T(regs) in the control of autoimmunity or suppression of activated effector T cells.


Assuntos
Núcleo Celular/metabolismo , Fatores de Transcrição Forkhead/metabolismo , Interleucina-7/farmacologia , Subpopulações de Linfócitos T/efeitos dos fármacos , Linfócitos T Reguladores/efeitos dos fármacos , Transporte Ativo do Núcleo Celular , Animais , Antígenos CD/genética , Antígenos CD/imunologia , Antígenos CD/metabolismo , Antígeno CTLA-4 , Diferenciação Celular/efeitos dos fármacos , Diferenciação Celular/imunologia , Células Cultivadas , Regulação da Expressão Gênica/efeitos dos fármacos , Regulação da Expressão Gênica/imunologia , Subunidade alfa de Receptor de Interleucina-2/biossíntese , Subunidade alfa de Receptor de Interleucina-7/biossíntese , Antígenos Comuns de Leucócito/genética , Antígenos Comuns de Leucócito/imunologia , Antígenos Comuns de Leucócito/metabolismo , Camundongos , Camundongos Endogâmicos BALB C , Camundongos Endogâmicos C57BL , Subpopulações de Linfócitos T/citologia , Subpopulações de Linfócitos T/imunologia , Subpopulações de Linfócitos T/metabolismo , Linfócitos T Reguladores/citologia , Linfócitos T Reguladores/imunologia , Linfócitos T Reguladores/metabolismo
5.
Transfus Clin Biol ; 26(4): 234-239, 2019 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-31277987

RESUMO

OBJECTIVES: The objectives of this study were to evaluate the prevalence of Human Pegivirus-1 (HPgV-1) viremia and genotype diversity among healthy blood donors from the Eastern Brazilian Amazon (city of Macapá, State of Amapá). There is little information for prevalence and circulation of HPgV-1 in this remote Brazilian region. MATERIALS AND METHODS: We conducted a study evaluating the HPgV-1 RNA prevalence and circulating genotypes in 431 volunteer blood donors originating from the Eastern Brazilian Amazon. The obtained HPgV-1 positive samples were submitted to sequencing and genotyping analysis in order to examine the genotype diversity of this virus in the Brazilian Amazon. RESULTS: Our results demonstrated a prevalence of HPgV-1 RNA in 9.5% of the tested blood donors. The phylogenetic analyses of the detected positive samples showed the presence of HPgV-1 genotypes 1, 2 and 3. The most frequently detected genotype was 2 (78.0% of the cases) represented by sub-genotypes 2A (39.0%) and 2B (39.0%). At lower rates, genotypes 1 (14.6%) and 3 (7.4%) were also detected. CONCLUSION: Our results revealed the presence of genotypes with European, Asiatic and African endemicity in Amazonian blood donors, probably due to the complex miscegenation processes that took place in this Brazilian region. More investigations, including information for the prevalence of HPgV-1 RNA in blood donors from other Latin American countries are needed to estimate the viremic rates and genotype distribution of this virus in a highly diverse continent like South America.


Assuntos
Doadores de Sangue , Infecções por Flaviviridae/epidemiologia , Vírus GB C/genética , Hepatite Viral Humana/epidemiologia , RNA Viral/sangue , Adolescente , Adulto , África/etnologia , Ásia/etnologia , Brasil/epidemiologia , Europa (Continente)/etnologia , Feminino , Infecções por Flaviviridae/virologia , Vírus GB C/isolamento & purificação , Genótipo , Hepatite Viral Humana/virologia , Migração Humana , Humanos , Indígenas Sul-Americanos/estatística & dados numéricos , Masculino , Pessoa de Meia-Idade , Filogenia , Análise de Sequência de RNA , Estudos Soroepidemiológicos , Adulto Jovem
6.
Pharmazie ; 63(10): 704-10, 2008 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-18972830

RESUMO

Dopamine delivery to the central nervous system (CNS) undergoes the permeability limitations of blood-brain barrier (BBB) which is a selective interface that excludes most water-soluble molecules from entering the brain. Neutral amino acids permeate the BBB by specific transport systems. Condensation of dopamine with neutral amino acids could afford potential prodrugs able to interact with the BBB endogenous transporters and easily enter the brain. The synthesis and characterization of the dopamine derivative 2-amino-N-[2-(3,4-dihydroxy-phenyl)-ethyl]-3-phenyl-propionamide (7) is described. The chemical and enzymatic stability of 7 was evaluated. The molecular weight (300 Da) and Log Papp (0.76) indicated that the physico-chemical characteristics of compound 7 are adequate to cross biological membranes. Compound 7 was enzymatically cleaved to free dopamine in rat brain homogenate (t1/2 = 460 min). In human plasma, the t1/2 of 7 was estimated comparable to that reported for L-DOPA. In view of a possible oral administration of 7, studies of its chemical behavior under conditions simulating those of the gastrointestinal tract showed that no dopamine production occurred; furthermore, 7 is able to permeate through a simulated intestinal mucosal membrane. The collected data suggest that compound 7 could beconsidered a very valuable candidate for subsequent in vivo evaluation.


Assuntos
Dopamina/administração & dosagem , Dopamina/farmacologia , Pró-Fármacos/síntese química , Pró-Fármacos/farmacologia , Animais , Soluções Tampão , Físico-Química , Sistemas de Liberação de Medicamentos , Humanos , Indicadores e Reagentes , Mucosa Intestinal/metabolismo , Espectroscopia de Ressonância Magnética , Membranas Artificiais , Ratos , Ratos Sprague-Dawley , Solubilidade
7.
Int J Immunopathol Pharmacol ; 18(3 Suppl): 21-31, 2005.
Artigo em Inglês | MEDLINE | ID: mdl-16848984

RESUMO

Tranbsuccal drug administration is an attractive method, as it has several advantages especially with respect to peroral delivery. Here we report: i) the aptitude of carbamazepine (CBZ) to penetrate porcine buccal mucosa and reconstituted human oral (RHO) epithelium; ii) three different tablet formulations for transbuccal administration; iii) the drug release rate from tablets. CBZ permeation through the buccal mucosa was investigated by using two different bi-compartmental open models: Franz cells for porcine buccal mucosa and Transwell diffusion cells system for RHO epithelium. Results, expressed as drug flux (Js) and permeability coefficients (Kp), indicated that CBZ well penetrates the membrane and arrives in the acceptor phase. Js and Kp resulted 7x10(-2) mg/cm2h and 0.23 cm/h for in vitro experiments and 1.81 x 10(-2) mg/cm2h and 4.57 x 10(-2) cm/h for ex vivo experiments. The flux is extensively affected by the membrane thickness. The CBZ release from three different formulations of tablets, prepared with loaded microspheres, loaded matrices, and conventional compressed physical mixture of components was studied. Using the new formulated "non-conventional" tablets prolonged drug release was obtained. Loaded matrix tablets discharged CBZ faster than microsphere tablets (17% and 12% in about 2.5 h respectively). Results indicate the possibility of administering CBZ on buccal mucosa.


Assuntos
Carbamazepina/administração & dosagem , Mucosa Bucal/metabolismo , Absorção , Administração Bucal , Animais , Carbamazepina/química , Carbamazepina/farmacocinética , Bochecha , Química Farmacêutica , Solubilidade , Suínos , Comprimidos
8.
Eur J Pharm Biopharm ; 59(1): 139-46, 2005 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-15567311

RESUMO

Ionizing radiation can be used as a drug sterilization technique, provided that the drug itself is not modified and that no toxic products are produced; moreover, if the irradiated product is a drug delivery system, the drug release characteristics must not be significantly altered by radiation. The aim of this work was to study the effects of sterilization by ionizing radiation on hydroxyethylcellulose/trehalose spherical micromatrices, containing the antibiotic vancomycin. Our experimental results showed that gamma-rays did not alter the chromophore groups of vancomycin (UV measurements), and did not modify the kinetic behavior of drug release from microspheres. Moreover, no significant changes in the shape and in the size distribution of microspheres were found after irradiation. The electron spin resonance (ESR) spectroscopy was proven to be a valid identification method of the executed radiation treatment, even after 5 years. The experimental results showed that the therapeutic application of the pharmacological system investigated was not compromised by irradiation, and that ESR spectroscopy can be used to distinguish irradiated from non-irradiated products.


Assuntos
Celulose/análogos & derivados , Celulose/efeitos da radiação , Raios gama , Microesferas , Trealose/efeitos da radiação , Vancomicina/efeitos da radiação , Celulose/química , Trealose/química , Vancomicina/química
9.
Neuroreport ; 11(5): 1081-4, 2000 Apr 07.
Artigo em Inglês | MEDLINE | ID: mdl-10790886

RESUMO

We report that extracellular matrix and neurons modulate the expression of occludin, one of the main components of tight junctions, by rat brain endothelial cells (RBE4.B). Of the three extracellular matrix proteins which we tested (collagen I, collagen IV, and laminin), collagen IV stimulated at the best the expression of occludin mRNA. The corresponding protein, however, was not synthesized. Significant amounts of occludin accumulated only when RBE4.B cells were cultured on collagen IV-coated inserts, in the presence of cortical neurons, plated on laminin-coated companion wells. Finally, occludin segregated at the cell periphery, only when endothelial cells were co-cultured with neurons for > or = 1 week.


Assuntos
Encéfalo/metabolismo , Endotélio Vascular/química , Endotélio Vascular/metabolismo , Matriz Extracelular/metabolismo , Proteínas de Membrana/genética , Proteínas de Membrana/metabolismo , Neurônios/metabolismo , Animais , Barreira Hematoencefálica/efeitos dos fármacos , Barreira Hematoencefálica/fisiologia , Encéfalo/citologia , Células Cultivadas , Circulação Cerebrovascular/fisiologia , Colágeno/farmacologia , Endotélio Vascular/efeitos dos fármacos , Matriz Extracelular/efeitos dos fármacos , Feto , Proteína Glial Fibrilar Ácida/metabolismo , Imuno-Histoquímica , Laminina/farmacologia , Proteínas de Neurofilamentos/metabolismo , Neurônios/efeitos dos fármacos , Ocludina , RNA Mensageiro/metabolismo , Ratos , Ratos Sprague-Dawley , Junções Íntimas/efeitos dos fármacos , Junções Íntimas/metabolismo , Fatores de Tempo
10.
J Control Release ; 76(1-2): 139-47, 2001 Sep 11.
Artigo em Inglês | MEDLINE | ID: mdl-11532320

RESUMO

Drug delivery to the central nervous system (CNS) is subject to the permeability limitations imposed by the blood-brain barrier (BBB). Several systems in vitro have been described to reproduce the physical and biochemical behavior of intact BBB, most of which lack the feature of the in vivo barrier. We developed a fully formed monolayer of RBE4.B immortalized rat brain microvessel endothelial cells (ECs), grown on top of polycarbonate filter inserts with cortical neuronal cells grown on the outside. Neurons induce ECs to synthesize and sort occludin to the cell periphery. Occludin localization is regulated by both compositions of the substratum and soluble signals released by cortical co-cultured neurons. The observed effects do not require strict physical contact among cells and neurons. To assess the physiological function of the barrier we examined the transendothelial transfer of three test compounds: dopamine, L-tryptophan and L-DOPA. Polycarbonate filter inserts, where ECs were co-cultured with neurons, were assumed as open two compartments vertical dynamic models. Permeation studies demonstrated that the ECs/neurons co-cultures possess permeability characteristics approaching those of a functional BBB: the system behaved as a selective interface that excludes dopamine permeation, yet permits L-tryptophan and L-DOPA to cross. The movement of test compounds from the donor to the acceptor compartment was observed at a distinct time from the start of co-culture. Transfer was determined using standard kinetic equations. Different performance was observed after 5 and 7 days of co-culture. After 5 days dopamine, L-tryptophan and L-DOPA passively permeate through the membrane as indicated by fittings with a first-order kinetic process equation. After 7 days of co-culture, occludin localizes at ECs periphery, dopamine does not cross the barrier to any further extent, while the transfer of L-tryptophan and L-DOPA fits well with a saturable Michaelis-Menten kinetic process, thus indicating the involvement of a specific carrier-mediated transport mechanism. Permeation studies confirmed that culture of ECs in the presence of neurons induces the characteristic permeability limitations of a functional BBB.


Assuntos
Barreira Hematoencefálica , Animais , Células Cultivadas , Dopamina/farmacocinética , Levodopa/farmacocinética , Permeabilidade , Ratos , Ratos Sprague-Dawley , Triptofano/farmacocinética
11.
Phys Med Biol ; 46(2): 461-71, 2001 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-11229726

RESUMO

Solid state pellets (1 mm thick) for electron spin resonance (ESR) dosimetry were made using ammonium tartrate as the radiation-sensitive substance. Their behaviour was experimentally investigated as a function of dose with 60Co gamma rays. The calibration function obtained permits measurements of absorbed dose in the 2-50 Gy range, with a combined uncertainty of +/-4%. The lowest detectable dose was about 0.5 Gy. These properties are comparable with or even better than those of ESR dosimeters made from other materials. The time stability of the ESR signal of ammonium tartrate dosimeters at different storage conditions after irradiation was studied. A rather complex behaviour was observed, which suggests that more species of free radicals are produced by radiation and that migration processes may be effective. No dependence of the response on beam quality was found for high-energy photon and electron beams produced by a linear accelerator used in radiotherapy, whereas dose was underestimated with low-energy x-rays.


Assuntos
Espectroscopia de Ressonância de Spin Eletrônica/métodos , Radiometria/métodos , Fenômenos Biofísicos , Biofísica , Elétrons/uso terapêutico , Radicais Livres/efeitos da radiação , Humanos , Microesferas , Tamanho da Partícula , Fótons/uso terapêutico , Radiometria/estatística & dados numéricos , Planejamento da Radioterapia Assistida por Computador , Tartaratos/efeitos da radiação
12.
Eur J Pharm Biopharm ; 52(1): 83-9, 2001 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-11438427

RESUMO

A new formulation, in which vancomycin is entrapped into trehalose and hydroxyethylcellulose (Natrosol) spherical matrices, is described. Microspheres were produced by the solvent evaporation method. The entrapped drug was fully recovered following microspheres dissolution. Differential scanning calorimetry analyses proved that Natrosol maintains trehalose in its amorphous form. The stabilizing effects of trehalose on vancomycin were evaluated even after long storage and heating of microspheres. Calorimetric data indicated no decomposition of the entrapped drug. In vitro drug release, already performed by using a general two-compartment linear time-invariant open model, suggests that the new delivery system is suitable for topical application on extensive and purulent or burn wounds, when the skin is heavily damaged and the barrier disrupted. The system activation is determined by osmotic phenomena. The prepared new delivery system seems to have characteristics suitable for topical applications on extensive and purulent wounds. The system is able to take away serous exudates from wounds, thus letting the matrix to swell and form a viscous gel-like dispersion that, in turn, enables drug diffusion.


Assuntos
Antibacterianos/administração & dosagem , Celulose/análogos & derivados , Celulose/administração & dosagem , Trealose/administração & dosagem , Vancomicina/administração & dosagem , Sistemas de Liberação de Medicamentos , Microesferas , Solubilidade , Vancomicina/química
13.
Pharmazie ; 53(12): 829-34, 1998 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-9879567

RESUMO

Some new derivatives of valproic acid (1) have been synthesized by condensation reaction of L-phenylalanine ethyl ester (2), L-tryptophan methyl ester (3), L-leucine methyl ester (4), L-methionine methyl ester (5) or L-histidine methyl ester (6) with 1 in the presence of dicyclohexylcarbodiimide (DCC). The reaction afforded in good yield prodrugs containing an amino acidic moiety. The structure of the new compounds was determined with the aid of spectroscopic and analytical data. To evaluate the stability following p.o., administration, the synthesized molecules were tested for gastro-intestinal hydrolysis. No significant general acid-base hydrolysis for the peptide bond was observed. The molecules offer a potentially useful mean to obtain highly selective drug release to the brain.


Assuntos
Aminoácidos/química , Anticonvulsivantes/síntese química , Pró-Fármacos/síntese química , Ácido Valproico/síntese química , Anticonvulsivantes/farmacocinética , Disponibilidade Biológica , Sistema Digestório/metabolismo , Hidrólise , Espectroscopia de Ressonância Magnética , Pró-Fármacos/farmacocinética , Ácido Valproico/farmacocinética
14.
Pharmazie ; 48(2): 123-6, 1993 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-8475158

RESUMO

White beeswax microspheres were investigated as a vehicle for the controlled release of anticancer agents. The in vitro diffusion of fluorouracil (1) and its prodrug ftorafur (2) was studied. The transfer rate constants from simulated gastro-intestinal juices to simulated plasma, throughout artificial wall lipid membranes, were defined. The constant's values suggested that the two drugs are poorly absorbed from stomach and main absorption occurred in the intestinal tract. Microspheres of 1 and 2 were prepared by a meltable dispersion of white beeswax and a wetting agent. The method is simple, inexpensive, rapid and reproducible. The drug release from the prepared microspheres was evaluated in vitro. More than 95% of the isolated microspheres were of particle size range 100-425 microns. The average drug content was 4%. Drug dissolution was greatly retarded as a result of microsphere formation.


Assuntos
Fluoruracila/administração & dosagem , Tegafur/administração & dosagem , Ceras , Preparações de Ação Retardada , Estabilidade de Medicamentos , Fluoruracila/química , Fluoruracila/farmacocinética , Microesferas , Tamanho da Partícula , Tegafur/química , Tegafur/farmacocinética
15.
Pharmazie ; 51(7): 487-9, 1996 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-8774840

RESUMO

The in vitro permeation behaviour of L-tryptophan (1). L-pyroglutamic acid (2), L-pyroglutamyl-L-tryptophan (3), and the corresponding ethyl ester derivatives (4, 5 and 6 respectively) was studied to collect the essential informations for oral administration of these molecules. Dipeptides 3 and 6 offer a potentially useful mean to facilitate diffusion across the blood-brain barrier (BBB) and enhance the rate of entry of drug molecules into the central nervous system (CNS). The transfer rate constants (Kd) from simulated gastro-intestinal juices to simulated plasma, throughout artificial wall lipid membranes, were defined. The Kd values suggested that the molecules are absorbed both in gastric and intestinal environments in about comparable amounts. Since peptide bonds are often rapidly broken down by enzymes of most biological fluids the enzymatic hydrolysis characteristics in natural gastro-intestinal environment were studied. While hydrolysis of the ester bond of 6 was about 12%, after 5 h no important hydrolysis was observed for peptide bond of 3 and 6.


Assuntos
Sistema Digestório/química , Dipeptídeos/química , Portadores de Fármacos/análise , Animais , Cromatografia Líquida de Alta Pressão , Difusão , Dipeptídeos/metabolismo , Estabilidade de Medicamentos , Mucosa Gástrica/metabolismo , Concentração de Íons de Hidrogênio , Hidrólise , Técnicas In Vitro , Mucosa Intestinal/metabolismo , Membranas Artificiais , Permeabilidade , Ácido Pirrolidonocarboxílico/análogos & derivados , Ratos , Espectrofotometria Ultravioleta
16.
Pharmazie ; 48(12): 917-20, 1993 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-8115437

RESUMO

Hexadecanol microspheres were investigated as a vehicle for the controlled release of valproic acid. Microsphere of the antiepileptic agent were prepared by the meltable dispersion method in water using wetting agents. To prevent hepatotoxicity, microspheres containing both the drug and vitamin E were also prepared. The method in simple, inexpensive, rapid and reproducible. The drug release was evaluated in vitro. Kinetic results were analyzed to distinguish between the first-order release model and the square root of time relationship. More than 99% of the isolated microspheres were particle size range 200-710 microns. The average drug content was 24%. Drug bioavailability was greatly affected as a result of microspheres formation.


Assuntos
Anticonvulsivantes/química , Ácido Valproico/química , Vitamina E/química , Aldeídos , Anticonvulsivantes/administração & dosagem , Preparações de Ação Retardada , Cinética , Microesferas , Modelos Biológicos , Tamanho da Partícula , Ácido Valproico/administração & dosagem , Vitamina E/administração & dosagem
17.
Bull Soc Pathol Exot ; 93(3): 193-7, 2000 Jul.
Artigo em Francês | MEDLINE | ID: mdl-11030056

RESUMO

To eradicate poliomyelitis and poliovirus, intensive vaccination campaigns with oral polio-vaccine (OPV) have been organised. Eradication campaigns may well be successful because the antiviral immunity and the local intestinal immunity due to OPV in particular avoids and/or limits poliovirus circulation. These campaigns give interesting opportunities for studying the impact of viral vaccines on the viral world in terms of ecological and genetic virology. The pre-eradication phase we are now entering brings with it two kinds of problems. First, the major disadvantage of OPV is the genetic and phenotypic variability of the vaccine strains. This variability leads to the spread of potentially pathogenic strains, which can be implicated in vaccine-associated paralytic poliomyelitis (VAPP). Genetic changes are characterised by point mutations and by genetic exchanges among OPV strains, between OPV and wild strains and perhaps between poliovirus and non-polio enteroviruses (ENPV). The fact that a few OPV mutant strains have been shown to multiply and/or to circulate for long periods suggests that OPV could sustain a reservoir of pathogenic poliovirus strains. Second, there are ecological considerations. The disappearance of wild poliovirus through OPV vaccination could be due not only to antiviral local immunity but also to competition between OPV strains and wild strains for infecting the digest tract. Moreover, a competition between OPV and other enteroviruses may take place in a common ecological niche. To our knowledge, the possible impact of intensive OPV vaccination campaigns on the ENPV populations has never been considered. Because the goal of poliovirus eradication may be reached in the near future, there is worry as to the possible evolution of ENPV towards highly epidemic and pathogenic strains. This is leading those laboratories involved in poliomyelitis surveillance not only to search for remaining wild poliovirus strains but also to study the possible long-term circulation of OPV strains and to develop efficient ENPV surveillance.


Assuntos
Enterovirus/fisiologia , Poliomielite/prevenção & controle , Vacina Antipólio Oral/efeitos adversos , Evolução Biológica , Enterovirus/genética , Variação Genética , Genótipo , Humanos , Intestinos/imunologia , Intestinos/virologia , Mutação , Fenótipo , Poliomielite/imunologia , Poliovirus/genética
18.
Clin Microbiol Infect ; 19(2): E118-28, 2013 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-23240764

RESUMO

Several haemorrhagic fevers are caused by highly pathogenic viruses that must be handled in Biosafety level 4 (BSL-4) containment. These zoonotic infections have an important impact on public health and the development of a rapid and differential diagnosis in case of outbreak in risk areas represents a critical priority. We have demonstrated the potential of a DNA resequencing microarray (PathogenID v2.0) for this purpose. The microarray was first validated in vitro using supernatants of cells infected with prototype strains from five different families of BSL-4 viruses (e.g. families Arenaviridae, Bunyaviridae, Filoviridae, Flaviviridae and Paramyxoviridae). RNA was amplified based on isothermal amplification by Phi29 polymerase before hybridization. We were able to detect and characterize Nipah virus and Crimean-Congo haemorrhagic fever virus (CCHFV) in the brains of experimentally infected animals. CCHFV was finally used as a paradigm for epidemics because of recent outbreaks in Turkey, Kosovo and Iran. Viral variants present in human sera were characterized by BLASTN analysis. Sensitivity was estimated to be 10(5) -10(6) PFU/mL of hybridized cDNA. Detection specificity was limited to viral sequences having ~13-14% of global divergence with the tiled sequence, or stretches of ~20 identical nucleotides. These results highlight the benefits of using the PathogenID v2.0 resequencing microarray to characterize geographical variants in the follow-up of haemorrhagic fever epidemics; to manage patients and protect communities; and in cases of bioterrorism.


Assuntos
Febres Hemorrágicas Virais/diagnóstico , Febres Hemorrágicas Virais/virologia , Técnicas de Diagnóstico Molecular/métodos , Análise de Sequência com Séries de Oligonucleotídeos/métodos , Virologia/métodos , Surtos de Doenças , Europa Oriental/epidemiologia , Febres Hemorrágicas Virais/epidemiologia , Humanos , Oriente Médio/epidemiologia , Sensibilidade e Especificidade
19.
J Clin Virol ; 56(3): 238-43, 2013 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-23219893

RESUMO

BACKGROUND: Resequencing DNA microarray (RMA) technology uses probes designed to identify a panel of viral sequences. It can be used for detecting emerging viruses by revealing the nucleotide polymorphisms within the target of interest. OBJECTIVES/STUDY DESIGN: As a new tool for molecular diagnosis of arbovirus infection, high density PathogenID v2.0 RMA (PID2-RMA) was assessed for the detection and genetic analysis of dengue, West Nile, and Chikungunya viruses in spiked blood samples or sera from individuals infected with dengue virus. Viral RNAs extracted from biological samples were retrotranscribed into cDNA and amplified using the Phi 29 polymerase-based method. This amplified cDNA was used for hybridization on PID2-RMA. RESULTS: A good specificity of RMA-based detection was demonstrated using a panel of arboviruses including Dengue, West Nile and Chikungunya viruses. This technology was also efficient for the detection and genetic analysis of the different serotypes of dengue virus in sera of infected patients. Furthermore, the mixing of dengue, West Nile and Chikungunya prototype viruses within a single sample of human blood did not interfere with the sensitivity of PID2-RMA. CONCLUSIONS: Our data show that high density PID2-RMA was suitable for the identification of medically important arboviruses. It appears to be particularly adapted to the genetic analysis of dengue, West Nile, and Chikungunya viruses in urgent clinical situations where the rapid identification and characterization of the pathogen is essential.


Assuntos
Infecções por Alphavirus/diagnóstico , Arbovírus/isolamento & purificação , Dengue/diagnóstico , Técnicas de Diagnóstico Molecular/métodos , Virologia/métodos , Febre do Nilo Ocidental/diagnóstico , Infecções por Alphavirus/virologia , Arbovírus/classificação , Arbovírus/genética , Febre de Chikungunya , Dengue/virologia , Humanos , Análise em Microsséries/métodos , Análise de Sequência de DNA/métodos , Febre do Nilo Ocidental/virologia
20.
Eur J Cancer Prev ; 22(5): 417-9, 2013 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-23222411

RESUMO

Susceptibility to esophageal carcinoma (EC) is influenced by the interaction between genetic and environmental factors. To clarify the etiology of EC, several genome-wide association studies have identified single nucleotide polymorphisms (SNPs) in PCLE1 and RFT2 genes as esophageal squamous cell carcinoma (ESCC) susceptibility loci in Asian populations. This study aimed to determine whether these SNPs also modify the risk of esophageal adenocarcinoma (EAC) and ESCC in western populations of Caucasian ethnicity. A European case-control study including 349 EC patients and 580 controls matched for age, sex, geographical location, and race was carried out. The SNPs rs2274223 in the PCLE1 gene at chromosome 10q23 and rs13042395 in the RFT2 gene at chromosome 20p13 were determined using PCR. Genotype distributions were compared between patients and controls, and odds ratios with 95% confidence intervals were calculated. The total EC group included 86 patients with ESCC and 258 patients with EAC. The distribution of PLCE1 and RFT2 genotypes did not differ between patients with EAC or ESSC, and the controls. In contrast to the modulation of the risk of ESCC in Asians, it is unlikely that the PLCE1 rs2274223 and RFT2 13042395 SNPs play a role in EAC or ESCC susceptibility in Dutch Caucasians.


Assuntos
Adenocarcinoma/genética , Carcinoma de Células Escamosas/genética , Neoplasias Esofágicas/genética , Proteínas de Membrana Transportadoras/genética , Fosfoinositídeo Fosfolipase C/genética , Polimorfismo de Nucleotídeo Único , Adenocarcinoma/epidemiologia , Carcinoma de Células Escamosas/epidemiologia , Estudos de Casos e Controles , Neoplasias Esofágicas/epidemiologia , Feminino , Predisposição Genética para Doença , Estudo de Associação Genômica Ampla , Humanos , Masculino , Países Baixos/epidemiologia , Polimorfismo de Nucleotídeo Único/fisiologia , Fatores de Risco , População Branca/estatística & dados numéricos
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