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1.
J Healthc Qual Res ; 38(2): 76-83, 2023.
Artículo en Inglés | MEDLINE | ID: mdl-36163149

RESUMEN

INTRODUCTION AND OBJECTIVES: Using the assessment of satisfaction of patients of labour room services, the caregiver or policymakers can identify the gaps in the implemented programmes and health policies. This study was aimed to design a valid and reliable satisfaction questionnaire that will help in identifying the aspects of gaps that need improvement. METHODS: A facility and community-based observational cross-sectional study was conducted in the district of western Uttar Pradesh (India) between January 2019 and August 2020. Validation of the structured questionnaire with 34 dichotomous questions categorized under five subscales was performed by evaluating its validity and reliability. A total of 380 beneficiaries were selected from 48 government health facilities. RESULTS: The calculated Content validity index was calculated to be 9.5 which was adequate as per the guidelines. The reliability analysis of the questionnaire showed that the internal consistency was high with an overall Cronbach's alpha of 0.710. The variation in Cronbach's alpha on the elimination of any question from the questionnaire ranged from 0.676 to 0.767. The mean patient satisfaction score in the total surveyed population was 24.39±4.684 (total score=34) and there was a greater variation in the satisfaction score of infrastructure when compared with other subscales. CONCLUSION: The findings from this study support the reliability and validity of the patient satisfaction questionnaire as it is capable of evaluating the satisfaction in terms of delivery services provided in labour rooms as a whole.


Asunto(s)
Instituciones de Salud , Satisfacción Personal , Humanos , Estudios Transversales , Reproducibilidad de los Resultados , Encuestas y Cuestionarios
2.
BMC Ecol ; 20(1): 30, 2020 05 11.
Artículo en Inglés | MEDLINE | ID: mdl-32393235

RESUMEN

BACKGROUND: The wild radishes, Raphanus raphanistrum and R. pugioniformis (Brassicaceae) are native to the East Mediterranean region. However, whereas R. raphanistrum is widely distributed worldwide, the endemic R. pugioniformis is limited to specific habitats. In R. raphanistrum the diaspores of the indehiscent fruits comprise glabrous, light, single-seeded segments, whereas the intact fruits of R. pugioniformis are heavy and covered with spiny backward-pointing trichomes. We aimed to investigate whether the structure of the diaspores was directly associated with long- and short-range dispersal in R. raphanistrum and R. pugioniformis, respectively. We further surveyed within-population spatial distributions, to test the hypothesis that short- and long-range dispersal contribute to a patchy vs. uniform distribution patterns of R. pugioniformis and R. raphanistrum, respectively. RESULTS: The results indicated that dispersal by wind and run-off water was substantially lower for diaspores of R. pugioniformis than for those of R. raphanistrum diaspores. Supporting the hypothesis that backward-pointing trichomes promote adherence to soil particles, the displacement on soil surface of R. pugioniformis fruits depended on their orientation relative to wind direction. Furthermore, trichome removal from fruits of R. pugioniformis significantly reduced wind velocity needed to remove fruits that were placed on soils typical of the species' natural habitats. The spatial-distribution survey results indicated a patchy distribution of R. pugioniformis populations as compared with the more uniform arrangement in the studied populations of R. raphanistrum; consistent with the unidirectional vs. homogeneous wind dispersal of the respective diaspores, with respect to wind direction. In addition, R. pugioniformis population sizes changed less between years than those of R. raphanistrum. CONCLUSIONS: Overall, our results indicate that fruit structure is strongly linked to dispersal ability and spatial distribution of the two closely related wild radish species. Whereas R. raphanistrum inhabits homogenous sandy soil habitats, the distribution range of R. pugioniformis includes heterogeneous environments in which growth niches are scarcer. We suggest that the different modes of dispersal have evolved as adaptive traits appropriate to the species' specific habitats.


Asunto(s)
Brassicaceae , Raphanus , Dispersión de Semillas , Demografía , Semillas
3.
RSC Adv ; 9(31): 17868-17876, 2019 Jun 04.
Artículo en Inglés | MEDLINE | ID: mdl-35520587

RESUMEN

We report a novel and simple approach for the synthesis of silver nanoparticles capped with inositol (Ag NPs/Ino) by the reduction of silver salt with ascorbic acid under basic conditions. UV-vis, TEM, FTIR and TGA techniques were used to characterize the Ag NPs/Ino to determine the size, shape and surface modification of the NPs. Stable silver nano-ink was prepared in aqueous solution containing 1% PVP (stabilizer) and glycerol (cosolvent) and was used for the direct-writing of a paper electrode with a roller ball-point pen for electrochemical applications. The solvent, stabilizing agents, concentration of NPs (10%), paper substrate, sintering temperature (40 °C) and sintering time (15 min) were optimized to obtain a uniform coating of Ag NPs on the paper substrate. Further, the synthesis and fabrication of ZnO NPs on a paper substrate was put forward to design a touch pad device based on the piezoelectric effect. The preparation of paper based devices suggests a direction for the development of a simple, low cost and compatible approach for the direct-writing of paper based flexible electrodes and electronics for future applications.

4.
Artículo en Inglés | MEDLINE | ID: mdl-22947647

RESUMEN

Polarized Raman spectra of pure and alanine doped tri-glycine sulfate (TGS) single crystals at 12 K in different scattering geometries are analyzed. Sub species modes due to three crystallographically distinguishable glycine ions G (I), G (II) and G (III) are assigned. It is observed that alanine doping does not change the crystalline field and acts as local perturbation only. The major changes due to doping are observed in the relative intensities of different modes; most of the modes associated with G (I) and SO(4)(2-) ions show reversal behavior in relative intensity at high doping concentration. The observed spectral changes are analyzed in terms of reorientation of G (I) ions with sub species modes of G (II)/ G (III) following the reorientation due to complex hydrogen bonding network.


Asunto(s)
Alanina/química , Glicina/química , Simulación de Dinámica Molecular , Oligopéptidos/química , Espectrometría Raman , Cristalización , Electricidad , Iones , Rayos Láser , Fonones , Sulfatos/química , Temperatura , Vibración
5.
J Food Sci ; 77(2): C156-61, 2012 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-22225422

RESUMEN

The aim of this study was to evaluate the in vitro antioxidant potential of hydro-ethanolic extract of a novel phytococktail comprising of sea buckthorn, apricot, and Rhodiola (SAR) from trans-Himalaya. The 1,1-diphenyl-2-picrylhydrazyl (DPPH) activity of the extract increased in a dose-dependent manner (upto 0.1 mg/mL), and was found to be about 38% of that of ascorbic acid at 0.1 mg/mL. The hydro-ethanolic extract of SAR also scavenged the ABTS(.+) radical generated by ABTS/potassium persulfate (PPS) system and was found to be about 62% of that of ascorbic acid at 0.1 mg/ mL. The total antioxidant power of the extract was determined by ferric reducing antioxidant power (FRAP) assay. Total phenolic content was found to be 1.28016 × 10(-3) mol gallic acid equivalent (GAE)/g extract. Total flavonoid and flavonol contents were estimated to be 2.5970 × 10(-4) mol and 4.87 × 10(-4) mol quercetin equivalent/g extract, respectively. The hydro-ethanolic extract of this phytococktail indicated presence of essential phytoconstituents of polyphenols, flavonoids, flavonols, and ascorbic acid, which contributed significantly to its antioxidant capacity. The combination of the 3 plants may well support their use in traditional medicine to combat oxidative stress and high-altitude sickness.


Asunto(s)
Antioxidantes/farmacología , Frutas/química , Extractos Vegetales/farmacología , Polifenoles/farmacología , Ácido Ascórbico/metabolismo , Benzotiazoles/metabolismo , Etanol/química , Ácido Gálico/metabolismo , Hippophae/química , Prunus/química , Rhodiola/química , Ácidos Sulfónicos/metabolismo
6.
J Environ Sci Eng ; 54(1): 21-6, 2012 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-23741854

RESUMEN

Concentrations of various organochlorine pesticides in a commercial fresh water catfish, Heteropneustes fossilis, were measured. This study reveals possible toxicological exposure of human beings by way of consuming such fish containing pesticide and that will amount to possible exposure. Tissue extracts obtained by Soxhlet apparatus were used for analysis and the concentrations of analytes were determined by gas chromatography with electron capture detection. The major organochlorines found in blood sample were Endosulfan, Alpha-HCH, Beta-HCH and Gamma-HCH. However, the organochlorines found in edible portion of fish (i.e.flesh) were mainly--Endosulfan, Delta-HCH, Aldrine, pp-DDE etc. The concentrations of these organochlorines were at or above the theoretical threshold limit and hence are supposed to be effectively toxic to fish eaters, due to biomagnification.


Asunto(s)
Hidrocarburos Clorados/sangre , Músculos/química , Plaguicidas/sangre , Animales , Bagres/sangre , Agua Dulce/análisis
7.
Food Chem Toxicol ; 39(1): 11-8, 2001 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-11259847

RESUMEN

Riboflavin (RF) is a known photoreactive and phototoxic molecule. However, unlike other photosensitizers, it does not induce photohaemolysis of erythrocytes by itself. On the other hand, illuminated RF caused haemolysis but in the presence of serum or plasma. The kinetics of photohaemolysis in the presence of serum/plasma has been studied by monitoring the rate of haemolysis spectrophotometrically and morphological changes at erythrocytes membrane by scanning electron microscopy. We found that the extent of mammalian RBC membrane damage was dependent on the concentration of RF or hematoporphyrin (HP) (0-20 microgram/ml) and dose of sunlight (0-20 min). The RBC membrane-damaging potential of illuminated HP was not affected by the presence of plasma in the reaction system. Furthermore, RF showed a protective role against photohaemolysis caused by photoexcited HP if erythrocytes were preincubated with RF in the absence of serum/plasma. For mechanistic studies, biochemical parameters such as acetylcholinesterase activity (AChE) and formation of TBA-reactive substance (TBA-RS) were analysed in RBC and RBC+plasma under a similar set of experimental conditions. We observed about a 25% decrease in AchE activity as a synergistic action of RF or HP (20 microgram/ml) and sunlight (30 min) in both cases (RBC or RBC+plasma). Interestingly, illuminated RF caused about a 125% increase of TBA-RS in a reaction system consisting of RBC+plasma. On the other hand, an increase in the production of TBA-RS by illuminated RF was not observed in the absence of plasma/serum, in the reaction system. These results suggested that photooxidation of RBC membrane lipids by illuminated RF, under the influence of plasma/serum, may be one of the causes of membrane modification leading to RBC lysis.


Asunto(s)
Acetilcolinesterasa/metabolismo , Membrana Eritrocítica/efectos de los fármacos , Hemólisis/efectos de los fármacos , Riboflavina/farmacología , Luz Solar , Animales , Membrana Eritrocítica/ultraestructura , Eritrocitos , Hematoporfirinas , Técnicas In Vitro , Cinética , Peróxidos Lipídicos/sangre , Ratones , Microscopía Electrónica de Rastreo , Ratas , Dosimetría Termoluminiscente , Sustancias Reactivas al Ácido Tiobarbitúrico/metabolismo
8.
Spectrochim Acta A Mol Biomol Spectrosc ; 56A(12): 2453-8, 2000 Nov 01.
Artículo en Inglés | MEDLINE | ID: mdl-11075687

RESUMEN

Dye-protein interactions are of immense importance in dye-ligand chromatography of protein purification. In this type of interactions, the structure of the dye molecules has a significant role. However, studies on the structure of these ligands are scanty. Therefore, we have spectroscopically investigated interactions of three 5-(aryl)azoquinolin-8-ol derivatives, which could be used as potent chelate forming agents, with bovine serum albumin (BSA). Among these, the carboxy derivative, 5-(2'-carboxyphenyl)azoquinolin-8-ol (CPAQ) has been selected for resonance Raman study. It has been shown that BSA has six independent binding sites for CPAQ at pH 7.2, the binding constant being 6.2 x 10(3) M(-1). Assignments of Raman modes of bound CPAQ are also presented. It has also been shown that bound CPAQ exists exclusively in hydrazone form. Results further demonstrate that the azo group nitrogen adjacent to the phenyl ring probably participated in the formation of a BSA-CPAQ complex.


Asunto(s)
Oxiquinolina/química , Oxiquinolina/metabolismo , Albúmina Sérica Bovina/química , Albúmina Sérica Bovina/metabolismo , Absorción , Sitios de Unión , Espectrometría Raman
9.
Artículo en Inglés | MEDLINE | ID: mdl-10595449

RESUMEN

The dissolving pulp industry, spread throughout the world, is the principal source of wood-hydrolysate effluent rich in hemicelluloses. This effluent is the major source of pollution in the industry. COD and BOD5 values of the effluent range from 60,000 to 103,000 and 42,000 to 78,000 mg/l respectively. Biomethanation of this effluent is the best possible treatment option for reducing the COD load and recovering the bioenergy embedded in the effluent. This paper deals with the study on the biphasic biomethanation of the wood-hydrolysate in upflow acidogenic reactor coupled with anaerobic filter methanogenic reactor. The two reactors were operated at organic loading rates of 69.6 and 30.1 g COD/l/d respectively. The overall COD, hemicelluloses and lignin reductions, and methane generation were observed to be 88%, 92%, 82% and 6.5 l/l reactor volume/d respectively. The relative size of the biphasic, anaerobic filter (mono-phasic) and upflow anaerobic sludge blanket (mono-phasic) reactors is found to be 1:1.6:2.03 respectively.


Asunto(s)
Metano/metabolismo , Eliminación de Residuos/métodos , Madera , Animales , Biomasa , Reactores Biológicos , Ácidos Carboxílicos/metabolismo , Contaminación Ambiental , Euryarchaeota , Concentración de Iones de Hidrógeno , Methanosarcina/metabolismo , Methanosarcinaceae/metabolismo , Oxidación-Reducción , Polisacáridos/metabolismo , Eliminación de Residuos/economía , Soluciones , Temperatura
10.
Indian J Biochem Biophys ; 35(3): 166-71, 1998 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-9803666

RESUMEN

Gelonin, a type 1 ribosome inactivating protein (RIP), having only one polypeptide chain, and which could be used against deadly diseases like cancer and AIDS is investigated spectroscopically through infrared (IR), diffused reflectance infrared fourier transform (DRIFT) and Raman techniques and observed vibrational modes are assigned. It is found that gelonin is having mainly alpha-helix and beta-sheet structure with some turn and disordered structure, the estimated percentage structure using Raman data being approximately 32% alpha-helix, approximately 20% beta-sheet, approximately 26% turn and approximately 22% disorder type. The temperature dependent infrared study of gelonin reveals its thermal stability, the denaturation temperature being around 60 degrees C and disordered contribution increasing with heating.


Asunto(s)
Proteínas de Plantas/química , Estructura Secundaria de Proteína , Desnaturalización Proteica , Proteínas Inactivadoras de Ribosomas Tipo 1 , Espectroscopía Infrarroja por Transformada de Fourier , Espectrometría Raman , Temperatura
11.
Artículo en Inglés | MEDLINE | ID: mdl-9523085

RESUMEN

A variety of ceramics and delivery systems have been used to deliver chemicals, biologicals, and drugs at various rates for desired periods of time from different sites of implantation. In vitro and in vivo studies have shown that ceramics can successfully be used as drug-delivery devices. Matrices, inserts, reservoirs, cements, and particles have been used to deliver a large variety of therapeutic agents such as antibiotics, anticancer drugs, anticoagulants, analgesics, growth factors, hormones, steroids, and vaccines. In this article, the advantages and disadvantages of conventional drug-delivery systems and the different approaches used to deliver chemical and biological agents by means of ceramic systems will be reviewed.


Asunto(s)
Cerámica , Sistemas de Liberación de Medicamentos/instrumentación , Preparaciones Farmacéuticas/administración & dosificación , Analgésicos/administración & dosificación , Animales , Antibacterianos/administración & dosificación , Fármacos Anti-VIH/administración & dosificación , Anticoagulantes/administración & dosificación , Antineoplásicos/administración & dosificación , Implantes de Medicamentos , Sustancias de Crecimiento/administración & dosificación , Hormonas/administración & dosificación , Humanos , Esteroides/administración & dosificación , Vacunas/administración & dosificación
12.
Biomed Sci Instrum ; 34: 13-7, 1997.
Artículo en Inglés | MEDLINE | ID: mdl-9603005

RESUMEN

Dexamethasone has been shown to stimulate bone nodule formation in vitro. A hydroxyapatite (HA) reservoir drug release device was designed to release dexamethasone in vitro. Two HA particle sizes (< 38 microns or 63-75 microns) were used to fabricate the reservoirs. Each HA reservoir was loaded with 2 mg of dexamethasone and suspended in 100 ml of 50% aqueous ethanol at 37 degrees C for a period of 28 days. The positive controls indicated a limited solubility of dexamethasone of 1.18 mg per 100 ml of 50% aqueous ethanol. Dexamethasone was not released from any of the HA reservoirs for the first 24 hours. The largest amount of dexamethasone (0.0137 microgram/microliter) was released from the 63-75 microns particle HA reservoirs. A significantly lesser amount (0.00855 microgram/microliter) of dexamethasone was released from the < 38 microns particle HA reservoirs. The results of this study suggest that a HA ceramic reservoir loaded with dexamethasone can be used to deliver dexamethasone over long periods of time.


Asunto(s)
Materiales Biocompatibles , Dexametasona/administración & dosificación , Sistemas de Liberación de Medicamentos , Durapatita , Glucocorticoides/administración & dosificación
13.
Biomed Sci Instrum ; 34: 59-64, 1997.
Artículo en Inglés | MEDLINE | ID: mdl-9603013

RESUMEN

Hydroxyapatite (HA) has been used to deliver therapeutic drugs both in vitro and in vivo at a constant rate showing zero order kinetics. This study was designed specifically to analyze the effects of wheat germ (WG) incorporation with HA on the rate of delivery of AZT from an insert system over a one month period in vitro. Insert systems which were saturated with wheat germ oil delivered AZT at a slower rate over the one month period than did half-saturated or unsaturated insert systems. All systems containing 50 mg of AZT in the outer shell delivered 80% of the 100 mg AZT dosage over the first eight days. The systems which had a 100 mg AZT insert surrounded by an oily HA shell lacking AZT delivered AZT in a linear manner over the course of one month. The amounts and rates of AZT release from composites was indirectly proportional to the amount of wheat germ oil used. The results of this study show that the lipids incorporated in the ceramic composites can be tailored to deliver a 100 mg AZT dosage for a period of one month in vitro.


Asunto(s)
Fármacos Anti-VIH/administración & dosificación , Materiales Biocompatibles , Cerámica , Durapatita , Aceites de Plantas , Inhibidores de la Transcriptasa Inversa/administración & dosificación , Zidovudina/administración & dosificación , Implantes de Medicamentos , Triticum
14.
Biomed Sci Instrum ; 34: 65-9, 1997.
Artículo en Inglés | MEDLINE | ID: mdl-9603014

RESUMEN

Interleukin-2 (IL-2) is a potentially effective cytokine to be used for cancer treatment. Since keeping IL-2 doses at a low, continuous level is important to avoid side effects which accompany high IL-2 doses, a ceramic which release IL-2 could prove to be a beneficial method of drug delivery for cancer patients [1]. In vitro studies were performed to determine the optimal hydroxyapatite (HA) to IL-2 ratio for continuous release of IL-2 from HA using both a matrix and insert ceramic pellet. In the matrix pellet experiment, HA to IL-2 ratios of 25:1, 50:1 and 100:1 were tested by compressing a homogenous mixture of each variable in triplicate and placing each ceramic in 2.5 mL simulated body fluid (SBF) at 37 degrees C. The fluid was collected and replaced for each ceramic every two hours for 12 hours and at 24 hours. The collected fluid was then assayed for IL-2 content. Pellets consisting of 25:1 ceramic to drug ratio delivered almost the entire amount of IL-2 at the fastest rate. Composites of 100:1 IL-2 to HA delivered the least amount of IL-2 at the slowest rate. Release of IL-2 from the 50:1 ratio pellets was intermediate with respect to speed and amount of delivery. In the insert pellet experiment, similar laboratory procedures were used to show that 100:1 ratio insert pellets delivered IL-2 at a slower rate and in lesser amounts than 50:1 ratio insert pellets. Results of this study show that HA can deliver IL-2 at different rates by varying the ratio of HA to IL-2 in both matrix and insert ceramic pellets.


Asunto(s)
Materiales Biocompatibles , Cerámica , Durapatita , Interleucina-2/administración & dosificación , Líquidos Corporales , Implantes de Medicamentos
15.
Biomed Sci Instrum ; 34: 70-5, 1997.
Artículo en Inglés | MEDLINE | ID: mdl-9603015

RESUMEN

Various studies have been conducted using hydroxyapatite (HA) to deliver therapeutic drugs over a long period of time. However, the rate of drug release from ceramics varies tremendously. Thus a study was designed to observe the effect of particle size, pressure, drug ratio, and the addition of a zinc stearate binder on the release of BSA from ceramics. Samples were collected every two hours for a 12 hour period. Three particle sizes were used in the study (< 38, 45-63, and 63-75 microns). Variations in particle size did not influence the release of BSA. Ceramics compressed at a pressure of 150 Mpa delivered more protein than pressures of 300 MPa, 450 MPa, and 900 MPa. Drug to ceramic ratio had the most significant effect. A ratio of 1:25 BSA to HA delivered the protein quickly whereas the 1:100 BSA to HA delivered BSA to HA delivered BSA slowly and in zero order kinetics. The addition of the zinc binder improved the quality of the composite and decreased the release rate of protein delivery when present in 5% or less of the total ceramic weight. HA ceramics can be used to deliver proteins at different rates by varying compression pressure and drug to HA ratio.


Asunto(s)
Materiales Biocompatibles , Cerámica , Durapatita , Proteínas/administración & dosificación , Implantes de Medicamentos , Tamaño de la Partícula , Albúmina Sérica Bovina/administración & dosificación
16.
Biomed Sci Instrum ; 33: 126-30, 1997.
Artículo en Inglés | MEDLINE | ID: mdl-9731347

RESUMEN

Six different blends of zinc calcium phosphorous oxide ceramics (ZCAP) were prepared by mixing and calcining powders (ZnO:CaO:P2O5) of weight percent ratio: 50:30:20, 48:32:20, 44:20:26, 40:40:20, 30:40:30, and 30:30:40. ZCAP is a resorbable bioceramic and has been used to repair bone defects and deliver drugs in a continuous manner. The chemical composition, porosity, and elements released on exposure to buffered Tris HCl were measured for each blend of ZCAP. The products of mixing and thermal reaction were beta-Ca3(PO4)2, alpha-CaZn2(PO4)2, and 2CaO.P2O5. Free calcium and/or zinc oxide was present in several blends. The components of ZCAP and their volume percentages influenced the interconnected porosity of ZCAP bioceramics. The interconnected porosity for all blends of ZCAP ranged from 35 to 38%. Pore sizes from these six blends of ZCAP ranged from less 1 micron to greater than 100 microns. Results of the 12 hour dissolution study showed that more calcium was released than zinc or phosphorous from all blends of ZCAP. Zinc was released in trace amounts from all blends of ZCAP. Release of phosphorous from the different blends of ZCAP was not detected by the procedures used to detect phosphorous in this investigation. These blends of ZCAP have the potential to be used as bone substitutes and probably long term treatment of zinc deficiency in humans.


Asunto(s)
Materiales Biocompatibles , Cerámica , Porosidad , Solubilidad
17.
Biomed Sci Instrum ; 33: 131-6, 1997.
Artículo en Inglés | MEDLINE | ID: mdl-9731348

RESUMEN

Testosterone has been shown to stimulate bone healing. However, large doses of testosterone are associated with liver damage and prostate enlargement. Continuous release of testosterone at the traumatized bone site could enhance healing without inducing systemic side effects. In this investigation a self-setting zinc sulfate calcium phosphate (ZSCAP) ceramic with and without testosterone was used to fill experimentally induced bone defects in rats. Each treatment group consisted of six albino, Holtzman rats. Groups I and II consisted of non-operated and sham-operated animals. Rats in Group III, IV, V, and VI were implanted with ZSCAP particulate ceramic powders (63-75 microns) containing 0.0, 0.5, 1.0, or 1.5 mg testosterone in a 2.3 mm defect in the femur of each rat. Radiographic and morphologic examination of the implant site at four, eight, and twelve weeks post surgery showed integration of the implant in the femur of each rat. Serum testosterone of all rats was assayed at four, eight, and twelve weeks post surgery. Differences in the serum testosterone levels of rats in the six groups were not significant. Results of this study suggest that a ZSCAP-testosterone composite can be used to repair traumatized bone without increasing the levels of testosterone in the systemic circulation.


Asunto(s)
Sustitutos de Huesos , Cerámica , Curación de Fractura/efectos de los fármacos , Testosterona/administración & dosificación , Animales , Sistemas de Liberación de Medicamentos , Implantes de Medicamentos , Fémur/efectos de los fármacos , Fémur/patología , Fémur/cirugía , Masculino , Ratas , Testosterona/sangre
18.
Biomed Sci Instrum ; 33: 143-8, 1997.
Artículo en Inglés | MEDLINE | ID: mdl-9731350

RESUMEN

Coumadin is an anticoagulant used in the treatment of patients with pulmonary thromboembolisms or those implanted with mechanical vascular devices. Its efficacy is complicated by side effects such as hemorrhaging. Administration of coumadin by the traditional routes of pills and injections causes wide fluctuations of the drug in plasma. Thus, experiments were conducted to develop a hydroxyapatite ceramic system for releasing coumadin in vivo continuously for 7-10 days. A series of preliminary in vivo experiments was conducted to determine an effective non-lethal therapeutic dosage of coumadin for rats. Homogenous matrices containing varying amounts of coumadin were implanted subcutaneously in rats and the blood clotting time was determined. Results of these experiments showed that one mg coumadin delivered from HA implants doubled the blood clotting time and did not induce fatal hemorrhage. Subsequent in vitro studies were conducted to determine the most efficient way to deliver coumadin at a slow and sustained rate. Results of these experiments suggested that a solid insert of one mg of compressed coumadin in a hydroxyapatite ceramic shell released the drug more slowly and efficiently than a homogenous matrix consisting of compressed coumadin and hydroxyapatite.


Asunto(s)
Anticoagulantes/administración & dosificación , Materiales Biocompatibles , Cerámica , Durapatita , Warfarina/administración & dosificación , Animales , Coagulación Sanguínea/efectos de los fármacos , Relación Dosis-Respuesta a Droga , Implantes de Medicamentos , Ratas , Ratas Sprague-Dawley
19.
Biomed Sci Instrum ; 33: 149-54, 1997.
Artículo en Inglés | MEDLINE | ID: mdl-9731351

RESUMEN

Dapsone is a drug which is administered orally, on a daily basis, for four to five years as a cure for leprosy. The major problems associated with dapsone therapy include hemolysis, methemoglobinemia and patient non-compliance. Cimetidine reduces the side effects of dapsone and increases its levels in the blood. A ceramic drug delivery system was developed to maintain therapeutic levels of dapsone for an extended period of time and to alleviate associated side effects. In vitro release of commercial dapsone tablets (100 mg) and cimetidine pellets (400 mg) from hydroxyapatite reservoirs was studied in 100 ml absolute ethanol at 37 degrees C. Hydroxyapatite (HA) reservoirs loaded with one dapsone tablet released the drug at the rate of 8.3 mg/day for nine days, after which a much slower release occurred for another three days. With a load of two dapsone tablets, the rate of release was 6.7 mg/day for four weeks. HA reservoirs loaded with one cimetidine pellet delivered the drug at a rate of 25 mg/day for sixteen days. Combining both drugs in a single reservoir did not affect their respective release rates. When implanted subcutaneously in rats, HA reservoirs loaded with one dapsone tablet appeared to be well tolerated. After nine weeks, 77 mg of dapsone had been released. These experiments showed that HA reservoirs can be used to deliver dapsone and cimetidine in vivo.


Asunto(s)
Materiales Biocompatibles , Dapsona/administración & dosificación , Durapatita , Leprostáticos/administración & dosificación , Animales , Cimetidina/administración & dosificación , Cimetidina/farmacocinética , Dapsona/farmacocinética , Implantes de Medicamentos , Leprostáticos/farmacocinética , Masculino , Ratas , Ratas Sprague-Dawley
20.
Biomed Sci Instrum ; 32: 63-70, 1996.
Artículo en Inglés | MEDLINE | ID: mdl-8672691

RESUMEN

Testosterone has been shown to stimulate bone healing. However, large doses of testosterone have been associated with liver damage and prostate enlargement. Sustained release of testosterone by a device placed next to a bone fracture could deliver effective amounts of the steroid necessary for bone healing without the adverse side effects associated with oral delivery or intramuscular injection. The release of 1 mg of testosterone into 1 ml of 50% ethanol from one-hour calcined hydroxyapatite (HA) ceramics (n = 6) and twelve-hour calcined HA ceramics (n = 6) was measured over four days. The twelve-hour calcined HA ceramics exhibited a consistently slower testosterone release. A 200mg HA/0.1% PLA/gentamicin (1mg) ceramic cylinder containing 0, 0.5, 1.0, or 1.5 mg testosterone was placed adjacent to a 4 x 1 x 1 mm femoral defect created in four equal groups of twenty-seven castrated male Sprague Dawley rats. After four weeks, none of the ceramics contained any residual testosterone. Histological examination showed that the traumatized bone of the animals implanted with testosterone-containing ceramics healed faster for the first four weeks than the controls. This data suggests that the twelve-hour calcined HA should be used to extend the release of testosterone to enhance healing of traumatized bone.


Asunto(s)
Implantes de Medicamentos , Testosterona/administración & dosificación , Animales , Cerámica , Durapatita , Curación de Fractura/efectos de los fármacos , Masculino , Ratas , Ratas Sprague-Dawley , Factores de Tiempo , Difracción de Rayos X
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