RESUMO
OBJECTIVE: Long-term storage of articular cartilage (AC) remains challenging due to poor post-thaw viability. An initial step towards addressing this issue is characterizing cryoprotectant (CPA) transport, since ensuring adequate CPA equilibration throughout the tissue offers protection during cooling. This study takes a systematic approach in determining CPA transport rates through bovine AC and uses that information in mathematical models to determine CPA equilibration times. DESIGN: Diffusion of high concentration single (6.9 M dimethyl sulfoxide (DMSO)) and multi-component CPA solutions (VS55, 3.1 M DMSO+2.2 M 1,2-propanediol (PD)+3.1 M formamide (FM)) was measured through AC using (1)H nuclear magnetic resonance (NMR) imaging and localized spectroscopy, respectively. Using experimentally calculated effective diffusivities, diffusion models describing CPA transport through the tissue matrix and across chondrocyte membranes were combined to design a CPA addition and removal scheme for a cartilage plug of clinically relevant dimensions. RESULTS: (1)H NMR imaging and localized spectroscopy experiments suggested that the permeation of CPAs through AC (5 mm diameter, 5-10 mm in thickness) took on the order of 4 h for full equilibration at 22 degrees C. Imaging clearly showed the permeation of DMSO into cartilage over time and localized spectroscopy was able to distinguish the permeation rates of the individual VS55 components and water. Experimentally measured diffusivity values were used in CPA addition/removal simulations with a cartilage plug of clinically relevant dimensions (5 mm diameter, 2 mm in thickness). Results suggested a multi-step approach for adding and removing high concentration CPAs, with the addition and removal each taking approximately 2 h to complete. CONCLUSIONS: This study provides a foundation for designing CPA addition and removal protocols for effective long-term storage of cartilage tissue using a novel approach to measure CPA permeation.
Assuntos
Cartilagem Articular/metabolismo , Permeabilidade da Membrana Celular/efeitos dos fármacos , Criopreservação/métodos , Crioprotetores/farmacologia , Dimetil Sulfóxido/farmacologia , Animais , Cartilagem Articular/química , Bovinos , Crioprotetores/análise , Dimetil Sulfóxido/análise , Espectroscopia de Ressonância Magnética/métodos , Modelos Biológicos , Permeabilidade , Fatores de TempoAssuntos
Inseticidas/química , Pirazóis/química , Solo , Adsorção , Índia , Inseticidas/análise , Pirazóis/análise , Clima TropicalAssuntos
Aspergillus/metabolismo , Cladosporium/metabolismo , Endossulfano/metabolismo , Inseticidas/metabolismo , Poluentes do Solo/metabolismo , Aspergillus/isolamento & purificação , Biodegradação Ambiental , Cladosporium/isolamento & purificação , Endossulfano/análise , Inseticidas/análise , Poluentes do Solo/análiseRESUMO
Starting from L-rhamnose, D-mannose and 2-amino-2-deoxy-D-glucose hydrochloride, two disaccharide blocks, namely, ethyl 2,4-di-O-benzyl-3-O-[(R)-1-(methoxycarbonyl)ethyl]-alpha-L-rhamnopyranos yl-(1-->3)-2-O-acetyl-4,6-di-O-benzyl-1-thio-alpha-D-mannopyranoside and 2-(trimethylsilyl)ethyl 2-O-acetyl-3,6-di-O-benzyl-alpha-D-mannopyranosyl-(1-->3)-4,6-di-O-benzy l-2-deoxy-2-phthalimido-beta-D-glucopyranoside, were synthesised and then allowed to react in the presence of N-iodosuccinimide and trifluoromethane sulfonic acid to give a tetrasaccharide derivative. This compound was converted into 2-(trimethylsilyl)ethyl 2,4-di-O-benzyl-3-O-[(R)-1-(methoxycarbonyl)ethyl]-alpha-L-rhamno- pyranosyl-(1-->3)-2-O-acetyl-4,6-di-O-benzyl-alpha-D-mannopyranosyl-(1-- >4)-2-O-acetyl-3,6-di-O-benzyl-alpha-D-mannopyranosyl-(1-->3)-2-acetamid o-4,6-di-O-benzyl-2-deoxy-beta-D-glucopyranoside, which on hydrogenolysis, afforded the methyl ester 2-(trimethylsilyl)ethyl glycoside of the tetrasaccharide related to the repeating unit of the O-antigen from Shigella dysenteriae type 5.
Assuntos
Antígenos de Bactérias/química , Antígenos O/química , Polissacarídeos/síntese química , Shigella dysenteriae/imunologia , Sequência de Carboidratos , Dissacarídeos/síntese química , Mesilatos/química , Modelos Químicos , Dados de Sequência Molecular , Succinimidas/químicaAssuntos
Descontaminação/métodos , Calefação , Temperatura Alta , Inseticidas/metabolismo , Nematoides/metabolismo , Compostos Organotiofosforados/metabolismo , Poluentes do Solo/metabolismo , Animais , Inseticidas/farmacologia , Compostos Organotiofosforados/farmacologia , Resíduos de Praguicidas/metabolismo , Distribuição Aleatória , Solo/parasitologia , Energia SolarAssuntos
Produtos Agrícolas/química , Fabaceae/química , Hexaclorocicloexano/análise , Inseticidas/análise , Resíduos de Praguicidas/análise , Plantas Medicinais , Produtos Agrícolas/metabolismo , Poeira/análise , Fabaceae/metabolismo , Meia-Vida , Hexaclorocicloexano/química , Hexaclorocicloexano/farmacocinética , Inseticidas/química , Inseticidas/farmacocinética , Isomerismo , Análise de RegressãoRESUMO
The review briefly covers the chromatographic techniques used in the analysis of organochlorine pesticide residues. The organochlorines ranging from DDT, HCH, the cyclodiene group and the polychloroterpene group have been covered. It endeavours to examine the existing methodologies and techniques including residue extraction, clean-up, chromatographic procedures involved in clean-up and determination and quantification of organochlorine residues by gas liquid chromatography from different substrates like food commodities, crops, soil and water.
Assuntos
Cromatografia/métodos , Contaminação de Alimentos/análise , Hidrocarbonetos Clorados , Inseticidas/análise , Resíduos de Praguicidas/análise , Poluentes do Solo/análise , Poluentes Químicos da Água/análiseAssuntos
Ração Animal/análise , Alimentos Infantis/análise , Controle de Pragas/normas , Resíduos de Praguicidas/metabolismo , Verduras/metabolismo , Ração Animal/normas , Cromatografia Gasosa , Análise de Alimentos , Contaminação de Alimentos , Humanos , Lactente , Alimentos Infantis/normas , Resíduos de Praguicidas/análise , Padrões de Referência , Relação Estrutura-Atividade , Verduras/normasRESUMO
A survey of dairy milk and milk products in and around Delhi, India, was undertaken to monitor the levels of DDT and HCH. The survey revealed that pesticide residue levels in milk often exceeded the limits recommended by the Food and Agriculture Organization/World Health Organization Expert Committee. Maximum residue levels of total HCH in milk (fat/whole milk basis) has not yet been prescribed. The 15 samples of dairy milk and 4 samples of milk products analyzed had residue levels ranging from 0.022 to 0.166 micrograms/g for HCH and from 0.042 to 0.382 micrograms/g for DDT.