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1.
Ecotoxicol Environ Saf ; 128: 189-94, 2016 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-26946283

RESUMEN

Calotropis procera L. is known as medicinal plant. The Phytochemical analyzes of its latex revealed that it possessed antioxidants, namely terpenes, phenolic compounds and cardenolides, flavonoids and saponins, while tannins, alkaloids and resin were absent in moderate to high concentration. In the present study, the role of latex of Calotropis procera as antioxidant and antiapoptotic was reported. To carry out this aim, fishes were exposed to 100 µg l(-1) 4-nonylphenol as chemical pollutant. The enzymes, superoxidase dismutase, catalase, acetlycholinstrase (AchE), glutathione s-transferase, cortisol, G6PDH) and apoptotic cells increased significantly (p<0.05) accompanied by irregular disturbance of (Na(+), K(+)) ions in the presence of 4-nonylphenol. On the other hand, these enzymes, ions, and apoptotic cells decreased normally and significantly (p<0.05) in the presence of latex. Total phenol content, total capacity antioxidant, reducing power decrease significantly (p<0.05) in the presence of 4-nonylphenol and increase normally in the presence of latex. Latex was used for the first time to protect catfish after 4-nonylphenol exposure. Our study confirms that crude latex of Calotropis procera possessed antioxidant and antiapoptotic activities against the toxicity of 4-Nonylphenol.


Asunto(s)
Antioxidantes/farmacología , Apoptosis/efectos de los fármacos , Calotropis/química , Bagres/metabolismo , Látex/farmacología , Fenoles/toxicidad , Contaminantes Químicos del Agua/toxicidad , Animales , Antioxidantes/aislamiento & purificación , Catalasa/sangre , Bagres/sangre , Eritrocitos/efectos de los fármacos , Eritrocitos/patología , Glutatión Transferasa/sangre , Látex/aislamiento & purificación , Masculino , Extractos Vegetales/química , Superóxido Dismutasa/sangre
2.
Bioorg Med Chem Lett ; 25(20): 4615-20, 2015 Oct 15.
Artículo en Inglés | MEDLINE | ID: mdl-26323871

RESUMEN

Three new cardenolides (3, 9 and 10), along with eight known ones, were isolated from the latex of Calotropis procera. The structural determination was accomplished by the 1D- and 2D-NMR spectra as well as HRESIMS analysis. The growth inhibitory activity of the latex and its sub-fractions as well as isolated compounds was evaluated against human A549 and Hela cell lines. The results exhibited that latex had strong growth inhibitory activity with IC50s of (3.37 µM, A-549) and (6.45 µM, Hela). Among the four extracts (hexane, chloroform, ethyl acetate and aqueous), chloroform extract displayed the highest potential cytotoxic activity, with IC50s of (0.985 µM, A-549) and (1.471 µM, Hela). All the isolated compounds displayed various degrees of cytotoxic activity and the highest activity was observed by calactin (1) with IC50s values of (0.036 µM, A-549) and (0.083 µM, Hela). None of these isolated compounds exhibited good antimicrobial activity evaluated by determination of their MICs using the broth microdilution method against various infectious pathogens. The structure-activity relationships for cytotoxic activity were also discussed.


Asunto(s)
Antibacterianos/farmacología , Antifúngicos/farmacología , Antineoplásicos Fitogénicos/farmacología , Calotropis/química , Cardenólidos/farmacología , Látex/química , Antibacterianos/química , Antibacterianos/aislamiento & purificación , Antifúngicos/química , Antifúngicos/aislamiento & purificación , Antineoplásicos Fitogénicos/química , Antineoplásicos Fitogénicos/aislamiento & purificación , Bacterias/efectos de los fármacos , Cardenólidos/química , Cardenólidos/aislamiento & purificación , Línea Celular Tumoral , Proliferación Celular/efectos de los fármacos , Relación Dosis-Respuesta a Droga , Ensayos de Selección de Medicamentos Antitumorales , Hongos/efectos de los fármacos , Células HeLa , Humanos , Pruebas de Sensibilidad Microbiana , Estructura Molecular , Relación Estructura-Actividad
3.
Int J Biol Macromol ; 253(Pt 6): 127277, 2023 Dec 31.
Artículo en Inglés | MEDLINE | ID: mdl-37806410

RESUMEN

For chemical modification, p-aminobenzoic acid was incorporated into chitosan Schiff base (ACsSB) and chitosan (ACs). Two ACs-based CuO nanoparticles composites; ACs/CuONPs-1 % and ACs/CuONPs-5 %, were also synthesized. Their structures were emphasized utilizing several analytical techniques; elemental analysis, FTIR, 1H NMR, XRD, SEM, EDX and TEM. Compared with standard cyclooxygenase (COX) inhibitor, Celecoxib, the prepared biomaterials showed in vitro selective inhibitory effectiveness against COX-2 enzyme that could be sorted, according to their MIC values that produce 50 % inhibition of COX-2 enzyme activity, as follows: Celecoxib (0.28 µg/mL) > ACs/CuONPs-5 % (4.1 µg/mL) > ACs/CuONPs-1 % (14.8 µg/mL) > ACs (38.5 µg/mL) > ACsSB (58.9 µg/mL) > chitosan (>125 µg/mL). Further, ACs/CuONPs-5 % has more in vitro inhibition efficiency towards Helicobacter pylori (H. pylori) than the other prepared biomaterials. Interestingly, the MIC value of 100 % growth inhibition of H. pylori for ACs/CuONP-5 % is equal to that of drug Clarithromycin (1.95 µg/mL). Thus, ACs/CuONPs-5 % has a promising potential as anti-H. pylori and selective anti-inflammatory agent. ACs/CuONPs-5 % is safe on the human gastric normal cells (GES-1). Therefore, amalgamation of both p-aminobenzoic acid and CuONPs into chitosan extremely promoted its anti-inflammatory and anti-H. pylori activity. This is a promising approach to achieve methods successful to compete the conventional antibiotics.


Asunto(s)
Quitosano , Helicobacter pylori , Nanopartículas del Metal , Nanopartículas , Humanos , Quitosano/farmacología , Quitosano/química , Materiales Biocompatibles/farmacología , Cobre/farmacología , Cobre/química , Ácido 4-Aminobenzoico , Celecoxib , Ciclooxigenasa 2 , Nanopartículas/química , Antibacterianos/farmacología , Antibacterianos/química , Antiinflamatorios , Óxidos , Nanopartículas del Metal/química
4.
Front Oral Health ; 4: 1211242, 2023.
Artículo en Inglés | MEDLINE | ID: mdl-38024146

RESUMEN

Background: Child neglect is a public health, human rights, and social problem, with potentially devastating and costly consequences. The aim of this study was to: (1) summarize the oral health profile of children across the globe; (2) provide a brief overview of legal instruments that can offer children protection from dental neglect; and (3) discuss the effectiveness of these legal instruments. Methods: We summarized and highlighted the caries profile and status of implementation of legislation on child dental neglect for 26 countries representing the World Health Organization regions: five countries in Africa (Nigeria, South Africa, Sudan, Tanzania, Zimbabwe), eight in the Americas (Argentina, Brazil, Canada, Chile, Mexico, Peru, Unites States of America, Uruguay), six in the Eastern Mediterranean (Egypt, Iran, Libya, Jordan, Qatar, Saudi Arabia), four in Europe (Italy, Latvia, Serbia, United Kingdom), two in South-East Asia (India and Indonesia) and one country (China) with its special administrative region (Hong Kong) in the Western Pacific. Results: Twenty-five of the 26 countries have legal instruments to address child neglect. Only two (8.0%) of these 25 countries had specific legal instruments on child dental neglect. Although child neglect laws can be interpreted to establish a case of child dental neglect, the latter may be difficult to establish in countries where governments have not addressed barriers that limit children's access to oral healthcare. Where there are specific legal instruments to address child dental neglect, a supportive social ecosystem has also been built to facilitate children's access to oral healthcare. A supportive legal environment, however, does not seem to confer extra protection against risks for untreated dental caries. Conclusions: The institution of specific country-level legislation on child dental neglect may not significantly reduce the national prevalence of untreated caries in children. It, however, increases the prospect for building a social ecosystem that may reduce the risk of untreated caries at the individual level. Social ecosystems to mitigate child dental neglect can be built when there is specific legislation against child dental neglect. It may be more effective to combine public health and human rights-based approaches, inclusive of an efficient criminal justice system to deal with child dental neglect.

5.
Biodegradation ; 23(5): 717-24, 2012 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-22453659

RESUMEN

A thermophilic Bacillus strain ASU7 was isolated from soil sample collected from Assiut governorate in Upper Egypt on latex rubber-containing medium at 45 °C. Genetically, the 16S bacterial ribosomal RNA gene of the strain ASU7 was amplified by the polymerase chain reaction (PCR) and sequenced. The sequence of the PCR product was compared with known 16S rRNA gene sequences in the GenBank database. Based on phylogenetic analyses, strain ASU7 was identified as Bacillus amyloliquefaciens. The strain was able to utilize Ficus elastica rubber latex as a sole source for carbon and energy. The ability for degradation was determined by measuring the increase in protein content of bacterium (mg/g dry wt), reduction in molecular weight (g/mol), and inherent viscosity (dl/g) of the latex. Moreover, the degradation was also confirmed by observing the growth of bacterium and formation of aldehyde or keto group using scanning electron microscopy (SEM) and shiff's reagent, respectively.


Asunto(s)
Bacillus/genética , Bacillus/aislamiento & purificación , Ficus/química , ARN Ribosómico 16S/genética , Goma/metabolismo , Análisis de Secuencia de ADN , Temperatura , Aldehídos/aislamiento & purificación , Bacillus/ultraestructura , Secuencia de Bases , Biodegradación Ambiental , Fraccionamiento Químico , Cromatografía en Gel , Egipto , Genes Bacterianos/genética , Cetonas/aislamiento & purificación , Datos de Secuencia Molecular , Filogenia , Bases de Schiff/química , Homología de Secuencia de Ácido Nucleico , Factores de Tiempo
6.
Molecules ; 17(12): 13969-88, 2012 Nov 26.
Artículo en Inglés | MEDLINE | ID: mdl-23183888

RESUMEN

Twelve novel intrinsically colored wholly aromatic azopolyamide-hydrazides containing various proportions of para- and meta-phenylene units were successfully synthesized by a low temperature (-10 °C) solution polycondensation reaction of either 4-amino-3-hydroxybenzhydrazide (4A3HBH) or 3-amino-4-hydroxybenzhydrazide (3A4HBH) with an equimolar amount of either 4,4'-azodibenzoyl chloride (4,4'ADBC), 3,3'-azodibenzoyl chloride (3,3'ADBC), or mixtures of various molar ratios of 4,4'ADBC and 3,3'ADBC in anhydrous N,N-dimethyl acetamide (DMAc) containing 3% (wt/v) LiCl as a solvent. The structures of the polymers were proven by elemental analysis, FTIR, ¹H- and ¹³C-NMR spectroscopy. The polymers' properties were strongly affected by their various structures. The intrinsic viscosities of the polymers were ranged from 0.7 to 4.75 dL g⁻¹ and increased with the para-phenylene units content. The polymers are partially soluble in DMAc, dimethyl formamide (DMF) and N-methyl-2-pyrrolidone (NMP). Their solubility increases with the introduction of meta-phenylene moieties into the polymer chains. The polymers exhibit a great affinity for water sorption. Their hydrophilicity increases as a function of the content of meta-phenylene rings incorporated into the polymer. Mechanical properties of the polymer films are improved markedly by substitution of para-phenylene units for meta-phenylene units. The completely para-oriented type polymer has the best thermal and thermo-oxidative stability relative to those of the other polymers.


Asunto(s)
Nylons/síntesis química , Polímeros , Relación Estructura-Actividad , Hidrazinas/química , Estructura Molecular , Nylons/química , Polímeros/síntesis química , Polímeros/química , Pirrolidinonas/química , Solubilidad , Espectroscopía Infrarroja por Transformada de Fourier , Agua/química
7.
Molecules ; 17(7): 7927-40, 2012 Jul 02.
Artículo en Inglés | MEDLINE | ID: mdl-22751259

RESUMEN

Biologically active N-benzoyl-4-(N-maleimido)-phenylhydrazide (BMPH) was synthesized and its structure was confirmed by elemental analysis and various spectral tools. It was examined as a thermal stabilizer and co-stabilizer for rigid poly (vinyl chloride) at 180 °C in air. Blending BMPH with reference samples in different ratios greatly lengthens the thermal stability value and improves the extent of discoloration of PVC. TGA confirmed the improved stability of PVC in presence of the investigated organic stabilizer. GPC measurements were done to investigate the changes occurred in the molecular masses of the degraded samples of blank PVC and PVC in presence of the novel stabilizer. BMPH showed good antimicrobial activity towards two kinds of bacteria and two kinds of fungi.


Asunto(s)
Antiinfecciosos/farmacología , Excipientes/farmacología , Fenilhidrazinas/farmacología , Cloruro de Polivinilo/química , Temperatura , Antiinfecciosos/síntesis química , Antiinfecciosos/química , Bacterias/efectos de los fármacos , Cromatografía en Gel , Color , Excipientes/síntesis química , Excipientes/química , Hongos/efectos de los fármacos , Halogenación/efectos de los fármacos , Espectroscopía de Resonancia Magnética , Pruebas de Sensibilidad Microbiana , Peso Molecular , Fenilhidrazinas/síntesis química , Fenilhidrazinas/química , Espectroscopía Infrarroja por Transformada de Fourier , Termogravimetría
8.
Oral Health Prev Dent ; 18(1): 1047-1053, 2020.
Artículo en Inglés | MEDLINE | ID: mdl-33499557

RESUMEN

PURPOSE: Three commercial restorative glass-ionomer cements (GICs) were modified with 5% and 10 wt/wt% nanodiamond (ND) particles incorporated into the powder of the GICs. The aim of the study was to assess the percentage of surface fluoride increase on different materials, following 2% neutral sodium fluoride gel application (2% NSF). Materials and Methods: The commercial GICs were: FN, Fuji IX GP (GC); KU, Ketac Universal (3M Oral Care); and RSC: Riva Self Cure (SDI). Grade 1 (Plasmachem) nanodiamond was used. Six specimens of each material were prepared using precise powder:liquid ratios. After a 10-min setting time, the GICs were polished. The specimens were randomly divided into two groups: control (group A) and test (group B). The samples were blot dried and group B received the 2% NSF gel for 2 min. The excess was wiped off with gauze and both groups were analyzed with SEM-EDS. Results: Data analysis revealed that all the GICs and their respective ND modifications had a statistically significant surface fluoride percentage increase (p < 0.0001) on the GICs in group B. The addition of ND10% w/w to FN (p < 0.001) and RSC (p = 0.029) resulted in statistically significant increase of surface fluoride percentage. KU remained consistent with no statistically significant increase noted between ND-modified KU and KU in group A or B. Conclusion: The ability of GICs to absorb the 2% NSF gel immediately after finishing of the restoration statistically significantly increases the fluoride percentage of the surface layer.


Asunto(s)
Nanodiamantes , Fluoruro de Sodio , Resinas Acrílicas , Fluoruros , Cementos de Ionómero Vítreo , Humanos , Ensayo de Materiales , Dióxido de Silicio
9.
Clin Exp Dent Res ; 6(1): 75-81, 2020 02.
Artículo en Inglés | MEDLINE | ID: mdl-32067394

RESUMEN

BACKGROUND: Children continue to suffer from the impact of the human immunodeficiency virus-acquired immunodeficiency syndrome (HIV/AIDS) pandemic. In Cape Town, these children receive medical care including antiretroviral therapy from facilities like Tygerberg Hospital's Paediatric Infectious Diseases Clinic. HIV-infected children may experience an increased caries experience when compared with their healthy peers. AIM: The aim of this study was to determine the oral health status of HIV-infected children younger than 12 years receiving antiviral drugs at the Paediatric Infectious Diseases Clinic. DESIGN: A cross-sectional survey was conducted among children aged between 2 and 12 years presenting at this clinic. Caregivers were interviewed to obtain information regarding health seeking behaviour, oral hygiene practices and dietary habits. A single clinician undertook a standardized clinical intraoral examination according to the World Health Organization guidelines, with modifications. RESULTS: Sixty-six children were recruited. A high prevalence of dental caries (78.8%) and an unmet treatment need of 90.4% were recorded among the participants. Most children had never visited the dentist, and those who did had mainly received emergency dental care. CONCLUSION: The high prevalence of severe dental caries in this population highlights the need for oral health awareness and the inclusion of oral health care in the comprehensive care of children with HIV. WHY THIS PAPER IS IMPORTANT TO PAEDIATRIC DENTISTS: The study highlights the importance of collaborating with health professions outside of dentistry. Doctors and nurses are often the first health professionals to come into contact with children with special needs. They should therefore be made aware of the early signs of decay so that these patients can be referred for dental treatment timeously. Holistic management of children with special healthcare needs is essential to improve their overall well-being.


Asunto(s)
Fármacos Anti-VIH/uso terapéutico , Atención Integral de Salud/organización & administración , Atención Odontológica/organización & administración , Caries Dental/epidemiología , Infecciones por VIH/complicaciones , Niño , Preescolar , Atención Integral de Salud/métodos , Estudios Transversales , Índice CPO , Caries Dental/diagnóstico , Caries Dental/inmunología , Caries Dental/prevención & control , Femenino , Infecciones por VIH/tratamiento farmacológico , Infecciones por VIH/inmunología , Necesidades y Demandas de Servicios de Salud , Hospitales Urbanos/organización & administración , Humanos , Masculino , Salud Bucal , Servicio Ambulatorio en Hospital/organización & administración , Prevalencia , Derivación y Consulta/organización & administración , Índice de Severidad de la Enfermedad , Sudáfrica/epidemiología
10.
J Clin Pediatr Dent ; 32(3): 247-52, 2008.
Artículo en Inglés | MEDLINE | ID: mdl-18524278

RESUMEN

OBJECTIVE: This retrospective survey highlighted the characteristics of children less than six years of age presenting with early childhood caries (ECC) who had two or more teeth extracted under intravenous sedation at the Tygerberg Oral Health Centre in Cape Town, South Africa. This survey was carried out in order to plan a community-appropriate intervention strategy. METHODS: Records of 140 patients kept by the pediatric Dentistry Division met the inclusion criteria and were included in this survey. Most of the patients originate from economically disadvantaged areas. RESULTS: Diet, feeding and oral hygiene habits were shown to be the most significant factors that contributed to the development of ECC in these patients. All the children were either breast- or bottle-fed past one year of age. 93.6% of the children went to sleep with the bottle or while on the breast and 90% of them were fed on demand during the night. On average, breastfeeding was stopped at 9 months of age compared to bottle-feeding that, on average, was stopped at a much later mean age of 23 months. Where oral hygiene practices were concerned, 52.6% of children brushed their own teeth without supervision. Frequency of brushing varied between subjects. CONCLUSION: The results of this study have demonstrated that there is a need for culturally appropriate education campaigns to inform parents (especially those in disadvantaged communities) about the importance of oral health and the prevention of oral disease.


Asunto(s)
Caries Dental/etiología , Caries Dental/prevención & control , Planificación en Salud , Alimentación con Biberón/efectos adversos , Lactancia Materna/efectos adversos , Preescolar , Caries Dental/epidemiología , Dieta Cariógena , Sacarosa en la Dieta/efectos adversos , Educación en Salud Dental , Humanos , Lactante , Estudios Retrospectivos , Padres Solteros , Sudáfrica/epidemiología , Cepillado Dental/estadística & datos numéricos , Desempleo , Poblaciones Vulnerables
11.
Health SA ; 23: 1039, 2018.
Artículo en Inglés | MEDLINE | ID: mdl-31934368

RESUMEN

BACKGROUND: Early childhood caries (ECC) is a particularly severe problem in low socio-economic communities which impacts the overall health and well-being of children. The extensive waiting lists for general anaesthesia and sedation services at the only tertiary dental care centre in the study area for the treatment of children with ECC were an indication of the extent of the problem. The true extent of the problem in this area was, however, not known. This information is crucial in order to plan and execute remedial measures. AIM: To assess the prevalence of oral and dental problems, especially ECC, in children under six years of age in the study population, and ascertain their need for dental treatment. METHODS: A cross-sectional survey of 659 children from selected schools and clinics in the study area was carried out between 2010 and 2013. RESULTS: A caries prevalence of 71.6% (472/659) was recorded. Of these, 67.5% (445/659) of children were in need of dental treatment. CONCLUSION: Over the last decade, there has been no improvement in the caries status of children in the study population, and no organised measures have been put in place to address this problem. Awareness needs to be raised so that governments, especially in developing countries, can take appropriate measures to alleviate this public health problem. Time and resources have to be invested in the education of all health professionals dealing with children, by raising their awareness of the early stages of the disease so that timeous referrals can be made.

12.
Acta Biomater Odontol Scand ; 4(1): 20-29, 2018.
Artículo en Inglés | MEDLINE | ID: mdl-29536024

RESUMEN

Aim: The purpose of the study was to assess the marginal adaptation and discrepancy of SSC's. Differences in adaptation and discrepancy between the four surfaces (mesial, lingual, distal, and buccal) were evaluated. Methods: The placement of stainless steel crowns were completed on a phantom head in accordance with the clinical technique. The ideal tooth preparation was made and this 'master tooth' duplicated to achieve a sample size of 15. The stainless steel crowns were placed, trimmed, and cemented as per the clinical technique. The cemented stainless crowns were analyzed under 100× stereomicroscope magnification. The marginal adaptation and discrepancy of each specimen was measured every 2 µm. Results: All the specimens showed marginal adaptation and discrepancy. The lingual margin had a significantly better adaptation (p < .0001) over the other surfaces. The buccal surface was the only surface that had an appropriate supra-CEJ level with a significance of p < .0001. Conclusion: The marginal discrepancies occur during the trimming procedure and assessment of the gingival approximation of the SSC margin. The inspection of stainless steel crown adaptation and discrepancy is an essential clinical step.

13.
Int J Biol Macromol ; 82: 589-98, 2016 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-26388182

RESUMEN

In this work, chitosan (CS) was cross-linked with different amounts of pyromellitimide benzoyl thiourea moieties. The structure of the cross-linked CS was confirmed by elemental analyses, FTIR and (1)H- NMR spectroscopy. The cross-linking process proceeds via reacting of the amino groups of CS with the isothiocyanate groups of the N,N'-bis [4-(isothiocyanate carbonyl)phenyl] pyromellitimide cross-linker. The amount of the cross-linker was varied with respect to CS to produce four new pyromellitimide benzoyl thiourea cross-linked CS (PIBTU-CS) hydrogels designated as PIBTU-CS-1, PIBTU-CS-2, PIBTU-CS-3, and PIBTU-CS-4 of increasing cross-linking degree percent of 11, 22, 44 and 88%, respectively. The scanning electron microscopy observation indicates the extremely porous structure of the hydrogels. XRD results showed that the crystallinity of CS was decreased upon cross-linking. The four hydrogels exhibit a higher antibacterial activity on Bacillus subtilis and Streptococcus pneumoniae as Gram positive bacteria and against Escherichia coli as Gram negative bacteria and higher antifungal activity on Aspergillus fumigatus, Syncephalastrum racemosum and Geotricum candidum than that of the parent CS as shown from their higher inhibition zone diameters and their lower MIC values. The swell ability of the hydrogel as well as their antimicrobial activity increased with increasing cross-linking density.


Asunto(s)
Antiinfecciosos/química , Antiinfecciosos/farmacología , Quitosano/química , Hidrogeles/química , Tiourea/química , Materiales Biocompatibles/química , Materiales Biocompatibles/farmacología , Hidrogeles/síntesis química , Espectroscopía de Resonancia Magnética , Solubilidad , Solventes , Espectroscopía Infrarroja por Transformada de Fourier , Tiourea/síntesis química , Difracción de Rayos X
14.
Mater Sci Eng C Mater Biol Appl ; 56: 363-73, 2015 Nov 01.
Artículo en Inglés | MEDLINE | ID: mdl-26249602

RESUMEN

Crosslinked poly(vinyl alcohol) (PVA)/carboxymethyl chitosan (CMCh) nanocomposites were synthesized using terephthaloyl diisothiocyanate crosslinker, in the presence of montmorillonite (MMT), in different ratios of the two matrices. Characterization of nanocomposites was performed using different analyses. Swelling behavior was studied in different buffered solutions. It was found that formation of crosslinked CMCh/PVA hydrogels increased the swellability. Metal ion adsorption has also been investigated. The results indicated that crosslinked CMCh adsorbs various metal ions much more than non crosslinked CMCh. Antimicrobial activity was examined against Gram positive bacteria, against Gram negative bacteria, and also against fungi. Results indicated that most of these nanocomposites exhibited good antimicrobial potency. Degradation study was carried out in Simulated Body Fluid (SBF) for different time periods in order to find out degradation index (Di). Results showed that weight loss of most of the nanocomposites increased as a function of incubation time.


Asunto(s)
Silicatos de Aluminio/química , Quitosano/análogos & derivados , Hidrogeles/síntesis química , Nanocompuestos/química , Alcohol Polivinílico/química , Antibacterianos/síntesis química , Antibacterianos/química , Bentonita/química , Quitosano/química , Arcilla , Bacterias Gramnegativas/crecimiento & desarrollo , Bacterias Grampositivas/crecimiento & desarrollo , Hidrogeles/química , Nanocompuestos/ultraestructura
15.
J Biomed Mater Res A ; 100(12): 3503-10, 2012 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-23015476

RESUMEN

N,N-Dimethyl-N'-(6-oxo-2-thioxo-1H-pyrimidine-4-yl)formamidine has been synthesized and introduced as a substituent in poly(vinyl chloride) (PVC) chains via a chemical reaction. Both the dimethyl derivative and the modified PVC have been characterized via spectroscopic analyses and their biological activities have been evaluated. Both IR and (1) H NMR spectral data confirm the incorporation of the newly prepared bioactive dimethyl pyrimidine derivative in the polymeric chains. The dimethyl pyrimidine derivative has exhibited good antibacterial and antifungal activities. The modified PVC shows higher antibacterial effects than that of the blank one. Photostabilizing efficiency of the modified PVC is determined by measuring the changes that occurred in the molecular weights of modified PVC samples after UV irradiation using the gel permeation chromatography technique. The extent of discoloration of the photodegraded modified PVC samples has also been measured. The results have been compared with that of the blank PVC and that of the PVC stabilized with phenyl salicylate as a reference UV absorber. The lower decrease in the values of weight average molecular weight, M(w) , at the first stages of UV irradiation and the absence of crosslinking at the latter stages of irradiation confirms the photostability of the modified PVC. The extent of discoloration of the modified sample is also decreased when compared with the blank and stabilized PVC samples.


Asunto(s)
Procesos Fotoquímicos/efectos de los fármacos , Cloruro de Polivinilo/síntesis química , Cloruro de Polivinilo/farmacología , Amidinas/química , Antiinfecciosos/farmacología , Bacterias/efectos de los fármacos , Cromatografía en Gel , Hongos/efectos de los fármacos , Espectroscopía de Resonancia Magnética , Pruebas de Sensibilidad Microbiana , Peso Molecular , Cloruro de Polivinilo/química , Pirimidinas/química , Espectrofotometría Infrarroja , Espectrofotometría Ultravioleta , Factores de Tiempo
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