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1.
Tech Coloproctol ; 27(11): 995-1005, 2023 11.
Artigo em Inglês | MEDLINE | ID: mdl-37414915

RESUMO

PURPOSE: Complete mesocolic excision (CME) has been associated with improved oncological outcomes in treatment of colon cancer. However, widespread adoption is limited partly because of the technical complexity and perceived risks of the approach. The aim of out study was to evaluate the safety of CME compared to standard resection and to compare robotic versus laparoscopic approaches. METHODS: Two parallel searches were undertaken in MEDLINE, Embase and Web of Science databases 12 December 2021. The first was to evaluate IDEAL stage 3 evidence to compare complication rates as a surrogate marker of perioperative safety between CME and standard resection. The second independent search compared lymph node yield and survival outcomes between minimally invasive approaches. RESULTS: There were four randomized control trials (n = 1422) comparing CME to standard resection, and three studies comparing laparoscopic (n = 164) to robotic (n = 161) approaches. Compared to standard resection, CME was associated with a reduction in Clavien-Dindo grade 3 or higher complication rates (3.56% vs. 7.24%, p = 0.002), reduced blood loss (113.1 ml vs. 137.6 ml, p < 0.0001) and greater mean lymph node harvest (25.6 vs. 20.9 nodes, p = 0.001). Between the robotic and laparoscopic groups, there were no significant differences in complication rates, blood loss, lymph node yield, 5-year disease-free survival (OR 1.05, p = 0.87) and overall survival (OR 0.83, p = 0.54). CONCLUSIONS: Our study demonstrated improved safety with CME. There was no difference in safety or survival outcomes between robotic and laparoscopic CME. The advantage of a robotic approach may lie in the reduced learning curve and an increased penetration of minimally invasive approach to CME. Further studies are required to explore this. PROSPERO ID: CRD42021287065.


Assuntos
Neoplasias do Colo , Laparoscopia , Mesocolo , Procedimentos Cirúrgicos Robóticos , Robótica , Humanos , Procedimentos Cirúrgicos Robóticos/efeitos adversos , Excisão de Linfonodo/efeitos adversos , Colectomia/efeitos adversos , Neoplasias do Colo/patologia , Mesocolo/cirurgia , Mesocolo/patologia , Laparoscopia/efeitos adversos , Resultado do Tratamento
2.
Osteoarthritis Cartilage ; 30(8): 1091-1102, 2022 08.
Artigo em Inglês | MEDLINE | ID: mdl-35339693

RESUMO

OBJECTIVES: Proteolytic destruction of articular cartilage, a major pathogenic mechanism in osteoarthritis (OA), was not previously investigated by terminomics strategies. We defined the degradome of human knee OA cartilage and the contribution therein of the protease HtrA1 using Terminal Amine Isotopic Labeling of Substrates (TAILS). DESIGN: Proteins from OA cartilage taken at knee arthroplasty (n = 6) or separately, from healthy cartilage incubated in triplicate with/without active HtrA1, were labeled at natural and proteolytically cleaved N-termini by reductive dimethylation, followed by trypsin digestion, enrichment of N-terminally labeled/blocked peptides, tandem mass spectrometry and positional peptide annotation to identify cleavage sites. Biglycan proteolysis by HtrA1 was validated biochemically and Amino-Terminal Oriented Mass Spectrometry of Substrates (ATOMS) was used to define the HtrA1 cleavage sites. RESULTS: We identified 10,155 unique internal peptides from 2,162 proteins, suggesting at least 10,797 cleavage sites in OA cartilage. 7,635 internal peptides originated in 371 extracellular matrix/secreted components, many undergoing extensive proteolysis. Rampant ragging of protein termini suggested pervasive exopeptidase activity. HtrA1, the most abundant protease in OA cartilage, experimentally generated 323 cleavages in 109 cartilage proteins, accounting for 171 observed cleavages in the OA degradome. ATOMS identified HtrA1 cleavage sites in a selected substrate, biglycan, whose direct cleavage by HtrA1 was thus orthogonally validated. CONCLUSIONS: OA cartilage demonstrates widespread proteolysis by endo- and exopeptidases. HtrA1 contributes broadly to cartilage proteolysis. Forward degradomics of OA cartilage together with reverse degradomics of proteases active in OA, e.g., HtrA1, can potentially fully annotate OA proteolytic pathways and provide new biomarkers.


Assuntos
Cartilagem Articular , Serina Peptidase 1 de Requerimento de Alta Temperatura A , Peptídeo Hidrolases , Biglicano/metabolismo , Cartilagem Articular/metabolismo , Serina Peptidase 1 de Requerimento de Alta Temperatura A/metabolismo , Humanos , Peptídeo Hidrolases/metabolismo , Peptídeos/metabolismo , Proteínas/metabolismo , Proteólise , Espectrometria de Massas em Tandem
3.
Nat Genet ; 5(1): 79-82, 1993 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-8220429

RESUMO

The expression of type X collagen is restricted to hypertrophic chondrocytes in regions undergoing endochondral ossification, such as growth plates. The precise function of type X collagen is unknown but the tissue-specific expression prompted us to examine the gene in hereditary disorders of cartilage and bone growth (osteochondrodysplasias). We have identified a 13 base pair deletion in one type X collagen allele segregating with autosomal dominant Schmid metaphyseal chondrodysplasia in a large Mormon kindred (lod score = 18.2 at theta = 0). The mutation produces a frameshift which alters the highly conserved C-terminal domain of the alpha 1(X) chain and reduces the length of the polypeptide by nine residues. This mutation may prevent association of the mutant polypeptide during trimer formation, resulting in a decreased amount of normal protein.


Assuntos
Colágeno/genética , Genes , Osteocondrodisplasias/genética , Alelos , Sequência de Aminoácidos , Animais , Sequência de Bases , Bovinos , Galinhas , Análise Mutacional de DNA , Genes Dominantes , Humanos , Camundongos , Dados de Sequência Molecular , Linhagem , Alinhamento de Sequência , Deleção de Sequência , Homologia de Sequência de Aminoácidos , Especificidade da Espécie
4.
Osteoarthritis Cartilage ; 18(3): 455-63, 2010 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-19909832

RESUMO

OBJECTIVE: Glucosamine has been previously shown to suppress cartilage aggrecan catabolism in explant cultures. We determined the effect of glucosamine on ADAMTS5 (a disintegrin-like and metalloprotease domain (reprolysin type) with thrombospondin type-1 motifs 5), a major aggrecanase in osteoarthritis, and investigated a potential mechanism underlying the observed effects. DESIGN: HEK293F and CHO-K1 cells transiently transfected with ADAMTS5 cDNA were treated with glucosamine or the related hexosamine mannosamine. Glucosamine effects on FURIN transcription were determined by quantitative RT-PCR. Effects on furin-mediated processing of ADAMTS5 zymogen, and aggrecan processing by glucosamine-treated cells, were determined by western blotting. Post-translational modification of furin and N-glycan deficient furin mutants generated by site-directed mutagenesis was analyzed by western blotting, and the mutants were evaluated for their ADAMTS5 processing ability in furin-deficient CHO-RPE.40 cells. RESULTS: Ten mM glucosamine and 5-10mM mannosamine reduced excision of the ADAMTS5 propeptide, indicating interference with the propeptide excision mechanism, although mannosamine compromised cell viability at these doses. Although glucosamine had no effect on furin mRNA levels, western blot of furin from glucosamine-treated cells suggested altered post-translational modification. Glucosamine treatment led to decreased glycosylation of cellular furin, with reduced furin autoactivation as the consequence. Recombinant furin treated with peptide N-glycanase F had reduced activity against a synthetic peptide substrate. Indeed, site-directed mutagenesis of two furin N-glycosylation sites, Asn(387) and Asn(440), abrogated furin activation and this mutant was unable to rescue ADAMTS5 processing in furin-deficient cells. CONCLUSIONS: Ten mM glucosamine reduces excision of the ADAMTS5 propeptide via interference with post-translational modification of furin and leads to reduced aggrecanase activity of ADAMTS5.


Assuntos
Proteínas ADAM/efeitos dos fármacos , Furina/efeitos dos fármacos , Glucosamina/metabolismo , Proteína ADAMTS5 , Western Blotting , Células Cultivadas , Humanos , Processamento de Proteína Pós-Traducional , Reação em Cadeia da Polimerase Via Transcriptase Reversa , Estatística como Assunto
5.
J Drug Target ; 15(2): 154-61, 2007 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-17365287

RESUMO

Carbamazepine (CBZ) is used in the treatment of generalized tonic clonic and partial seizures. In seizure disorder the focal point of treatment is brain. At present no commercial parenteral formulation of CBZ is available. We developed o/w nanoemulsions of CBZ stabilized by 1-O-alkylglycerol/lecithin for intravenous administration and evaluated the brain targeting potential of these formulations. The nanoemulsions were characterized for globule size, zeta potential (ZP), CBZ content and in vivo tissue distribution in mice. The in vivo data revealed a significant uptake of CBZ in all tissues. Among the nanoemulsions, 1-O-decylglycerol stabilized system showed significantly higher tissue levels and availability of CBZ. Particularly for this system 2.37 times higher brain availability and a brain/serum concentration ratio of 3.0 at 30 min is an important finding. This indicates the brain targeting potential. A systematic formulation development of CBZ nanoemulsions employing 1-O-alkylglycerols might pave way to achieve selective brain delivery of this important antiepileptic drug.


Assuntos
Anticonvulsivantes/administração & dosagem , Carbamazepina/administração & dosagem , Emulsões , Glicerol/análogos & derivados , Nanotecnologia , Animais , Anticonvulsivantes/farmacocinética , Carbamazepina/farmacocinética , Cromatografia Líquida de Alta Pressão , Glicerol/química , Infusões Intravenosas , Masculino , Camundongos , Distribuição Tecidual
6.
J Vet Intern Med ; 31(2): 532-538, 2017 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-28158899

RESUMO

Musladin-Lueke syndrome (MLS), previously termed Chinese Beagle syndrome, is an autosomal-recessive connective tissue disorder characterized by extensive fibrosis of the skin and joints that was first identified in Beagles in the 1970s. Recent research identified a founder mutation (c.660C>T; p.R221C) in the ADAMTSL2 gene in Beagles with MLS. Here, we report the detailed clinical phenotype and laboratory findings in 2 Beagles affected with MLS. We discuss these findings in relation to the human disorder geleophysic dysplasia (GD), which also arises from recessive ADAMTSL2 mutations, and recent findings in Adamtsl2-deficient mice.


Assuntos
Doenças do Cão/genética , Artropatias/veterinária , Anormalidades da Pele/veterinária , Animais , Doenças do Desenvolvimento Ósseo/genética , Doenças do Desenvolvimento Ósseo/patologia , Doenças do Cão/patologia , Cães , Feminino , Humanos , Artropatias/genética , Artropatias/patologia , Deformidades Congênitas dos Membros/genética , Deformidades Congênitas dos Membros/patologia , Masculino , Camundongos , Fenótipo , Anormalidades da Pele/genética , Anormalidades da Pele/patologia
7.
Matrix Biol ; 19(2): 185-7, 2000 May.
Artigo em Inglês | MEDLINE | ID: mdl-10842103

RESUMO

Adam9, Adam15 and Adam21, genes encoding members of the ADAM or MDC family of metalloproteases, have been mapped to mouse chromosomes 8, 1, and 12, respectively, using an interspecific cross. The mapping of these mouse loci and the extrapolated loci for their human orthologs may facilitate the mapping of diseases involving these genes.


Assuntos
Mapeamento Cromossômico , Desintegrinas/genética , Proteínas de Membrana/genética , Metaloendopeptidases/genética , Proteínas ADAM , Animais , Mapeamento Cromossômico/métodos , Ligação Genética , Humanos , Camundongos , Camundongos Endogâmicos C3H
8.
FEBS Lett ; 265(1-2): 104-6, 1990 Jun 04.
Artigo em Inglês | MEDLINE | ID: mdl-2365047

RESUMO

Biotransformation of rac-1(3)-O-hexadecylglycerol by photomixotrophic rape (Brassica napus) cells in suspension culture leads to 1-O-hexadecyl-2-acyl-sn-glycero-3-phosphocholines and small proportions of other ether lipids, e.g. 1-O-hexadecyl-2-acyl-sn-glycero-3-phosphoethanolamines. Reaction of the hexadecylacyl-glycerophosphocholines with ethanolamine in the presence of phospholipase D from Streptomyces chromofuscus yields additional hexadecylacylglycerophosphoethanolamines. Partial hydrolysis of the combined hexadecylacylglycerophosphoethanolamines followed by reacylation of the resulting lyso compound with palmitic anhydride gives 1-O-hexadecyl-2-palmitoyl-sn-glycero-3-phospho-(N-palmitoyl) ethanolamine, a nontoxic ether glycerophospholipid with antitumor activity. The corresponding 1-O-tetradecyl,1-O-octadecyl, and 1-O-[(Z)-9'-octadecnyl] derivatives are prepared similarly.


Assuntos
Antineoplásicos/síntese química , Brassica/metabolismo , Éteres de Glicerila/metabolismo , Fosfatidiletanolaminas/metabolismo , Biotransformação , Células Cultivadas , Éteres de Glicerila/síntese química , Indicadores e Reagentes , Fosfatidiletanolaminas/síntese química , Fosfolipase D/metabolismo , Streptomyces/enzimologia
9.
FEBS Lett ; 363(3): 304-6, 1995 Apr 24.
Artigo em Inglês | MEDLINE | ID: mdl-7737422

RESUMO

We have cloned the cDNA encoding the mouse DAD1 (defender against apoptotic cell death) protein. While showing an expected high homology with the previously cloned human and Xenopus DAD1-encoding cDNAs, this sequence has striking homology to partial cDNA sequences reported from O. sativa (rice) and C. elegans (nematode), suggesting the existence of plant and invertebrate homologs of this highly conserved gene. The human and mouse DAD1 genes map to chromosome 14q11-q12 and chromosome 14, respectively. This mapping data supports and extends the previously reported similarities between human chromosome 14q and mouse chromosome 14.


Assuntos
Proteínas de Membrana , Proteínas/genética , Proteínas de Xenopus , Sequência de Aminoácidos , Animais , Apoptose , Proteínas Reguladoras de Apoptose , Sequência de Bases , Mapeamento Cromossômico , Cromossomos Humanos Par 14 , Primers do DNA/química , Humanos , Camundongos , Dados de Sequência Molecular , Alinhamento de Sequência , Homologia de Sequência de Aminoácidos
10.
FEBS Lett ; 401(2-3): 213-7, 1997 Jan 20.
Artigo em Inglês | MEDLINE | ID: mdl-9013889

RESUMO

We have isolated cDNA clones corresponding to a new member of the murine tissue inhibitor of metalloproteinase (TIMP) family, designated Timp-4. The nucleotide sequence predicts a protein of 22,609 Da that contains the characteristic 12 cysteine TIMP signature. TIMP-4 is more closely related to TIMP-2 and TIMP-3 than to TIMP-1 (48%, 45% and 38% identity, respectively). Analysis of Timp-4 mRNA expression in adult mouse tissues indicated a 1.2 kb transcript in brain, heart, ovary and skeletal muscle. This pattern of expression distinguishes Timp-4 from other Timps, suggesting that the TIMP-4 protein may be an important tissue-specific regulator of extracellular matrix remodelling.


Assuntos
Metaloendopeptidases/antagonistas & inibidores , Proteínas/genética , Inibidores Teciduais de Metaloproteinases , Sequência de Aminoácidos , Animais , Sequência de Bases , Clonagem Molecular , DNA Complementar , Inibidores Enzimáticos , Masculino , Camundongos , Dados de Sequência Molecular , RNA/genética , Homologia de Sequência de Aminoácidos , Inibidor Tecidual 4 de Metaloproteinase
11.
J Histochem Cytochem ; 46(2): 221-9, 1998 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-9446829

RESUMO

The extracellular matrix proteolytic machinery is known to play a major role in trophoblast invasion, a process that shares similar features with the pathology of tumor invasion. In this study we investigated the expression of the recently described membrane-type matrix metalloproteinase-1 (MT-MMP-1; MMP-14) in early human placenta and decidual membrane to determine whether it might play a role in invasion. With in situ hybridization, the cytotrophoblasts of trophoblastic columns and the infiltrating intermediate trophoblasts in the decidual membrane were found to be the main producers of MT-MMP-1 mRNA. Gene expression was also seen in the villous double-layered trophoblastic epithelium and in the decidual cells of the decidual membrane. In endothelial and fibroblastic cells, however, the hybridization signal was either very weak or nonexistent. Immunohistochemical analysis and immunoelectron microscopy correlated well with the in situ hybridization findings. The most significant exception to this consisted of pericytes of spiral arteries, which appeared to lack MT-MMP-1 mRNA but showed intensive intracytoplasmic staining for the antigen. Our results show that MT-MMP-1 mRNA production is highly characteristic of intermediate trophoblasts, and MT-MMP-1 may have general importance in the tissue organization of early human placenta. We propose that MT-MMP-1 could be one of the key enzymes in the process of trophoblast invasion, acting alone or as a cell-surface activator of other proteinases.


Assuntos
Colagenases/biossíntese , Placenta/enzimologia , Trofoblastos/enzimologia , Vilosidades Coriônicas/enzimologia , Colagenases/análise , Colagenases/genética , Decídua/enzimologia , Implantação do Embrião , Feminino , Expressão Gênica , Humanos , Técnicas Imunoenzimáticas , Hibridização In Situ , Metaloproteinase 1 da Matriz , Microscopia Imunoeletrônica , RNA Mensageiro/análise , RNA Mensageiro/genética
12.
Invest Ophthalmol Vis Sci ; 38(5): 817-23, 1997 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-9112976

RESUMO

PURPOSE: It has been established that Sorsby's fundus dystrophy, a dominantly inherited form of blindness, is caused by mutations in the tissue inhibitor of metalloproteinase-3 (TIMP-3) gene. Because choroidal neovascularization is a prominent feature of Sorsby's fundus dystrophy, the authors have examined whether TIMP-3 protein plays a role in the regulation of angiogenesis. METHODS: Chemotaxis of endothelial cells toward vascular endothelial growth factor (VEGF) and basic fibroblast growth factor (bFGF) was examined using a modified Boyden chamber assay. Endothelial cells placed in the upper chamber were allowed to migrate through a polycarbonate membrane with 8 microns pores toward VEGF or bFGF present in the lower chamber. Next, the ability of TIMP-3 to inhibit chemotaxis was studied by incubating the cells with varying amounts of TIMP-3 during the assay. Finally, an in vitro angiogenesis assay was performed on collagen gels. Endothelial cells were seeded onto three-dimensional collagen gels. Treatment with bFGF and VEGF induced invasion of the gel and the formation of tube-like structures. TIMPs (1, 2, and 3) were added to the cultures to determine their effect on invasion. An in vivo chorioallantoic membrane (CAM) assay was performed using methylcellulose discs containing bFGF with or without TIMP-3. Induction of new blood vessels was observed with a stereomicroscope. RESULTS: TIMP-3 inhibits chemotaxis of vascular endothelial cells toward VEGF and bFGF, inhibits collagen gel invasion and capillary morphogenesis in vitro, and inhibits bFGF-induced angiogenesis in the CAM assay in vivo. CONCLUSIONS: TIMP-3 has the potential to inhibit angiogenesis. These results allow us to speculate on a possible mechanism by which mutant TIMP-3 protein might contribute to the Sorsby fundus dystrophy phenotype.


Assuntos
Alantoide/irrigação sanguínea , Córion/irrigação sanguínea , Neovascularização Patológica/prevenção & controle , Inibidores de Proteases/farmacologia , Proteínas/farmacologia , Alantoide/efeitos dos fármacos , Animais , Divisão Celular , Quimiotaxia/efeitos dos fármacos , Embrião de Galinha , Córion/efeitos dos fármacos , Cultura em Câmaras de Difusão , Fatores de Crescimento Endotelial/metabolismo , Endotélio Vascular/citologia , Endotélio Vascular/efeitos dos fármacos , Endotélio Vascular/fisiologia , Fator 2 de Crescimento de Fibroblastos/metabolismo , Fator 2 de Crescimento de Fibroblastos/farmacologia , Humanos , Linfocinas/metabolismo , Neovascularização Patológica/induzido quimicamente , Inibidor Tecidual de Metaloproteinase-3 , Fator A de Crescimento do Endotélio Vascular , Fatores de Crescimento do Endotélio Vascular
13.
Br J Ophthalmol ; 82(11): 1329-34, 1998 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-9924344

RESUMO

BACKGROUND/AIMS: Tissue inhibitor of metalloproteinases-3 (TIMP-3) is normally synthesised by the retinal pigment epithelium (RPE) and deposited in Bruch's membrane. Mutations in the TIMP3 gene cause Sorsby's fundus dystrophy (SFD), which is characterised by thickening of Bruch's membrane, choroidal neovascularisation, and photoreceptor degeneration. To elucidate the role of TIMP-3 in human retinal degenerative diseases, we immunolocalised TIMP-3 in eyes with SFD caused by the Ser-181-Cys TIMP3 gene mutation or retinitis pigmentosa (RP; not caused by TIMP3 mutations). METHODS: Standard light microscopic immunocytochemistry, including antigen retrieval, was used to localise TIMP-3 in paraffin sections of human eyes: two with SFD, three with different genetic forms of RP, and two normal. RESULTS: In the SFD eyes, the thickened Bruch's membrane was strongly TIMP-3 positive except where RPE cells had degenerated. Similarly, in the RP eyes, Bruch's membrane was TIMP-3 positive except where RPE cells were lost, consistent with ongoing RPE mediated turnover of TIMP-3 in this region. In areas of total photoreceptor loss, migrated RPE cells formed cuffs around blood vessels in the RP retinas. Thick, TIMP-3 positive extracellular matrix (ECM) deposits associated with the migrated RPE cells occluded some vascular lumina, correlating with the observed loss of inner retinal neurons in RP. CONCLUSIONS: TIMP-3 is a component of the increased ECM sequestered in Bruch's membrane in SFD. Further information is needed on normal TIMP-3/ECM interactions in Bruch's membrane and the effect of mutant TIMP-3 on this process. The finding of TIMP-3 accumulations in retinas with RP not caused by TIMP-3 mutations emphasises the importance of ECM remodelling in normal and diseased human eyes.


Assuntos
Olho/metabolismo , Retinose Pigmentar/metabolismo , Inibidor Tecidual de Metaloproteinase-3/metabolismo , Idoso , Idoso de 80 Anos ou mais , Lâmina Basilar da Corioide/metabolismo , Corioide/metabolismo , Células Epiteliais , Feminino , Humanos , Mutação , Reação do Ácido Periódico de Schiff , Retina/metabolismo , Vasos Retinianos , Retinose Pigmentar/genética , Inibidor Tecidual de Metaloproteinase-3/genética
14.
Int J Pharm ; 271(1-2): 95-113, 2004 Mar 01.
Artigo em Inglês | MEDLINE | ID: mdl-15129977

RESUMO

Vesicles with biological activity or with a targeting function in addition to carrier properties will have an added advantage. Vesicles prepared with amphiphiles having antioxidant property may have potential applications towards disorders implicated with reactive oxygen species. Ascorbyl palmitate (ASP) was explored as bilayer vesicle forming material. It formed vesicles (Aspasomes) in combination with cholesterol and a negatively charged lipid (dicetyl phosphate). Aspasomes were prepared by film hydration method followed by sonication in which aqueous azidothymidine (AZT) solution was encapsulated in aqueous regions of bilayer. Aspasomes were obtained with all compositions containing 18-72 mol% cholesterol. Differential scanning calorimetric data of aspasome dispersion and anhydrous mixtures of ascorbyl palmitate, cholesterol and dicetyl phosphate confirm the formation of bilayered vesicles with ascorbyl palmitate. Cholesterol content in aspasome did not exhibit any relation with vesicle size, zeta potential or percent entrapment. A substantial change in release rate of azidothymidine from aspasome was noticed on varying the proportion of cholesterol. Release rate and cholesterol content in Aspasomes did not exhibit any relation. A preparation with 45 mol% of cholesterol showed maximum retardation in release rate, than other compositions. The change in capture volume with time (latency) was studied for 8 h and with such a short duration study it was difficult to predict long term stability of these vesicles. But release experiments do indicate stability up to 18 h. Percent reducing activity of aspasome was estimated by measuring the absorbance of alpha,alpha-diphenyl-beta-picrylhydrazyl (DPPH) at 517 nm after addition of test antioxidant samples. These studies revealed that the antioxidant potency of ascorbyl moiety is retained even after converting ascorbyl palmitate into vesicles (Aspasomes). The antioxidant potency of Aspasomes was assessed by measuring the protection offered by this preparation against quinolinic acid induced lipoperoxidation of whole human blood in vitro, where in the lipoperoxidation was monitored by measuring thiobarbituric acid reactive substances (TBARS) levels. Aspasome rendered much better antioxidant activity than ascorbic acid. Transdermal permeation of aspasomal AZT, ASP-AZT aqueous dispersion and AZT-solution across excised rat skin was investigated in vitro using Franz diffusion cell. Permeation of aspasomal AZT was much higher than the other two preparations. However, ASP-AZT aqueous dispersion has also enhanced permeation of AZT significantly over the AZT-solution, indicating skin permeation enhancing property of ascorbyl palmitate.


Assuntos
Ácido Ascórbico/análogos & derivados , Ácido Ascórbico/química , Portadores de Fármacos/química , Animais , Antioxidantes/administração & dosagem , Antioxidantes/química , Antioxidantes/farmacocinética , Varredura Diferencial de Calorimetria , Química Farmacêutica , Colesterol/química , Estabilidade de Medicamentos , Técnicas In Vitro , Bicamadas Lipídicas/química , Peroxidação de Lipídeos , Organofosfatos/química , Tamanho da Partícula , Ratos , Absorção Cutânea , Solubilidade , Zidovudina/administração & dosagem , Zidovudina/química , Zidovudina/farmacocinética
15.
Int J Pharm ; 246(1-2): 187-97, 2002 Oct 10.
Artigo em Inglês | MEDLINE | ID: mdl-12270621

RESUMO

1-O-alkylglycerols (ALKG) have exhibited several biological activities and a prominent effect on blood-brain barrier permeability. They have markedly improved brain uptake of cancerostatic agents. Since ALKG are amphiphilic, we explored their tendency to assemble into bilayer vesicles, which can be applied as carriers for drugs. Vesicles (Algosomes) were formed by film hydration method using ALKG (tetra-, penta-, hexa-, hepta-, octa- or nona-decylglycerols) in combination with cholesterol (CHOL) and dicetyl phosphate (DCP) (1-O-alkylglycerol:CHOL:DCP in 45:45:10 molar ratio). On microscopic examination, the algosomes were found to be conspicuously spherical and the dispersion was a mixture of multi-lamellar and small-unilamellar vesicles. Phase transition temperatures of 1-O-hexadecylglycerol (HXDG) and CHOL mixtures were tested by differential scanning calorimetry (DSC). The changes in phase transition temperatures indicate the vesicle forming tendency of ALKG in presence of CHOL. Alkyl chain length dependent variations in vesicle size, zeta-potential (ZP) and capture volume (CV) could not be observed. Vesicles of 1-O-tetradecylglycerol (TTDG) showed improvement in CV with increase in CHOL content from 15 to 55 mol%. However the vesicle size decreased. On challenging algosomes with hypertonic salt solution [potassium iodide (KI) in water], vesicle size decreased and thus algosomes were found to be osmotically sensitive. Algosome dispersions on addition of higher concentrations of KI (40-100 mM) brought about increases in vesicle size and at concentrations 60 mM and above showed aggregation. All vesicular dispersions were stable for only a few days.


Assuntos
Glicerol/análogos & derivados , Glicerol/química , Transporte Biológico , Varredura Diferencial de Calorimetria , Cromatografia Líquida de Alta Pressão , Portadores de Fármacos , Estabilidade de Medicamentos , Osmose , Fotomicrografia , Fatores de Tempo , Zidovudina/química
16.
Lipids ; 26(12): 1086-92, 1991 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-1819691

RESUMO

Plant cells in culture are capable of incorporating exogenous 1-O-alkyl-sn-glycerols into various neutral and ionic ether lipids. 1-O-Alkyl-2-acyl-sn-glycero-3-phosphocholines, the major class of compounds thus formed, are used for the preparation of platelet activating factor (PAF) in high yields. Similarly, the prochiral 2-O-alkyl-sn-glycerols are transformed to chiral 2-O-alkyl glycerophospholipids from which compounds can be obtained that exhibit antiviral activity in plant and animal cells. Reaction of 1-O-alkyl-2-acyl-sn-glycero-3-phosphocholines with phospholipase D in the presence of ethanolamine leads to 1-O-alkyl-2-acyl-sn-glycero-3-phosphoethanolamines, which serve as starting material for the preparation of 1-O-alkyl-2-acyl-sn-glycero-3-phospho-(N-acyl)ethanolamines, compounds known to have antitumor activity.


Assuntos
Éteres de Glicerila/metabolismo , Plantas/metabolismo , Fator de Ativação de Plaquetas/biossíntese , Biotransformação , Células Cultivadas
17.
J Bone Joint Surg Br ; 76(5): 837-43, 1994 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-8083281

RESUMO

We studied the cellular response to physeal distraction in the growth plates of skeletally immature rabbits. We used a new method of labelling and detection of proliferating cells with bromodeoxyuridine (BUdR) and an anti-BUdR antibody. The application of an external fixator but no distraction force produced no changes in the growth plates. After five days of distraction at a maximum force of 20 N, the growth plate became thicker, mainly because of an increase in the number of hypertrophic chondrocytes, but there was no evidence of increased cell proliferation. Recent fractures were seen at the junction of growth plate and metaphysis but the increase in bone length was insignificant. After ten days of distraction at the same maximum force, the chondrocyte columns had become disorganised and cell proliferation was significantly decreased. There was an increase in bone length due to distraction of the fracture gap. In this model, physeal distraction did not stimulate cell proliferation, but actually inhibited it. The apparent increase in growth-plate thickness produced by distraction is not due to increased cell production, but results from inhibition of endochondral ossification and the consequent accumulation of hypertrophic chondrocytes. Any growth after distraction depends on the ability of growth-plate chondrocytes to divide. The decrease in proliferative activity which we found after ten days of distraction suggests the need for caution in the use of such procedures in young children.


Assuntos
Fixadores Externos , Lâmina de Crescimento/patologia , Hiperostose/patologia , Tíbia/patologia , Animais , Animais Recém-Nascidos , Bromodesoxiuridina , Divisão Celular , Lâmina de Crescimento/diagnóstico por imagem , Hiperostose/etiologia , Masculino , Modelos Biológicos , Coelhos , Radiografia , Tíbia/diagnóstico por imagem , Tíbia/cirurgia
18.
J Colloid Interface Sci ; 251(2): 360-5, 2002 Jul 15.
Artigo em Inglês | MEDLINE | ID: mdl-16290741

RESUMO

Monomers of some amphiphiles organize into bilayers to form liposomes and niosomes. Such bilayers are unstable or leaky and hence cholesterol is a common ingredient included to stabilize them. Cholesterol stabilizes bilayers, prevents leakiness, and retards permeation of solutes enclosed in the aqueous core of these vesicles. Other than cholesterol a material with good bilayer-stabilizing properties is yet to be identified. We have substituted cholesterol with fatty alcohols in niosomes containing polyglyceryl-3-di-isostearate (PGDS) and polysorbate-80 (PS-80) to explore their membrane-stabilizing property via permeation studies. Niosomes of polyglyceryl-3-di-isostearate, fatty alcohol/cholesterol, and polysorbate were prepared by ether injection method. Aqueous solution of ketorolac tromethamine (KT) was entrapped in them. The effects of alkyl chain length of fatty alcohols (C(12), C(14), C(16), C(18), and C(16+18)), of acyl chain length of polyoxyethylene sorbitan monoester surfactants, and of the molar ratio of lipid mixture on the release rate of ketorolac from niosomes were assessed by employing modified dissolution-dialysis method. Niosomes with cholesterol or fatty alcohols have exhibited a common release pattern. Niosomes containing fatty alcohol showed a considerably slower release rate of KT than those containing cholesterol. Based on the release rate, fatty alcohols can be ranked as stearyl

Assuntos
Colesterol/química , Álcoois Graxos/química , Lipossomos/química
19.
Drug Metabol Drug Interact ; 15(1): 71-81, 1999.
Artigo em Inglês | MEDLINE | ID: mdl-10707114

RESUMO

Circadian variation in the disease activity of rheumatoid arthritis has been established. Several nonsteroidal anti-inflammatory drugs have been studied for their chronokinetic behaviour. Time dependent influence of diazepam on the pharmacokinetics of diclofenac and naproxen has been reported. We report the time dependent influence of diazepam on the pharmacokinetics of ibuprofen in healthy subjects. Either ibuprofen or ibuprofen with diazepam was administered at 10.00 or 22.00 hours to eight healthy volunteers in a randomized crossover study. Serum ibuprofen levels were estimated by high performance liquid chromatography. There was a significant (p < 0.05) increase in mean elimination half life (2.39 +/- 0.42 to 3.59 +/- 0.35 h) following ibuprofen and diazepam administration compared to ibuprofen alone administered at 22.00 hours. The mean clearance of ibuprofen was therefore lowered from 62.7 +/- 8.9 to 41.7 +/- 2.6 ml/h/kg under the influence of diazepam during the night. Such a time dependent influence of diazepam on the pharmacokinetics of ibuprofen may be due to circadian variation in the pattern of protein production in the liver and/or competitive protein binding of the two drugs during the dark period.


Assuntos
Anti-Inflamatórios não Esteroides/farmacocinética , Cronoterapia , Diazepam/administração & dosagem , Hipnóticos e Sedativos/administração & dosagem , Ibuprofeno/farmacocinética , Adulto , Anti-Inflamatórios não Esteroides/sangue , Estudos Cross-Over , Diazepam/farmacocinética , Esquema de Medicação , Interações Medicamentosas , Humanos , Hipnóticos e Sedativos/farmacocinética , Ibuprofeno/sangue , Masculino
20.
Indian J Lepr ; 69(2): 179-81, 1997.
Artigo em Inglês | MEDLINE | ID: mdl-9290970

RESUMO

While extracting the M. leprae from the nasal flushings of leprosy patients it was found that these organisms were trapped in the waxy layer, between the aqueous and the chloroform layers. Thin layer chromotography (TLC) analysis of this layer, using chloroform-methanol-water system, revealed different spots when sprayed with acid alcohol and heated at 160 degrees C. The TLC profile of lipids of lepromatous and borderline (MB according to the WHO terminology) leprosy patients was distinctly different from that of tuberculoid leprosy patients and normal human volunteers. A simple, economical and fast procedure to characterize patients belonging to different spectra has been developed.


Assuntos
Hanseníase/diagnóstico , Metabolismo dos Lipídeos , Mycobacterium leprae/isolamento & purificação , Mucosa Nasal/microbiologia , Cromatografia em Camada Fina , Diagnóstico Diferencial , Humanos , Hanseníase/classificação , Mucosa Nasal/metabolismo
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