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1.
Br J Oral Maxillofac Surg ; 59(9): 982-992, 2021 11.
Artigo em Inglês | MEDLINE | ID: mdl-34503859

RESUMO

Osteomyelitis is an inflammatory infectious disease that affects bone and bone marrow. Histopathology remains the gold standard method for diagnosis, but imaging modalities also play an important role. We systematically reviewed five articles with comparative studies on plain films, computed tomography (CT) scan, magnetic resonance imaging (MRI), cone beam computed tomography (CBCT), positron emission tomography (PET), single photon-emission computed tomography (SPECT), scintigraphy, and SPECT/CT. Scintigraphy and SPECT/CT has the highest sensitivity of 100%. PET is only to be used in cases of follow up. Orthopantomography (OPG) is the most common initial diagnostic tool despite its low sensitivity. CT provides the necessary specificity needed for radionuclide imaging, which has the highest negative predictive value of 100% and a positive predictive value >95%. SPECT/CT with 100% sensitivity and 85% specificity can be considered as the imaging modality of choice for initial diagnosis and follow up.


Assuntos
Osteomielite , Tomografia por Emissão de Pósitrons , Humanos , Imageamento por Ressonância Magnética , Osteomielite/diagnóstico por imagem , Sensibilidade e Especificidade , Tomografia Computadorizada de Emissão de Fóton Único , Tomografia Computadorizada por Raios X
2.
Int J Oral Maxillofac Surg ; 50(5): 619-626, 2021 May.
Artigo em Inglês | MEDLINE | ID: mdl-33059994

RESUMO

Intralesional sclerotherapy for lymphatic malformations (LMs) has become a modality of choice because of the high morbidity and recurrence rates with surgical excision. Traditionally, the macrocystic variant has shown good results with sclerotherapy. This prospective study was performed to evaluate the role of bleomycin sclerotherapy in the management of different radiological variants of LM. A total of 142 patients were included in this study. The lesions were classified as macrocystic, microcystic, or mixed LMs on the basis of ultrasonography. All patients were managed by intralesional injection of bleomycin and were recalled after 4 weeks for evaluation. Colour photographs of the patients were taken before the onset of treatment and at each monthly visit, and were utilized to assess the response. Following the second, third, and fourth doses, the response was better in patients with the macrocystic variant than in those with the other two variants. However, after the completion of six doses, 80.3% of patients with the macrocystic variant, 67.4% with the microcystic variant, and 71.4% with the mixed type had a complete response. There was no difference in the overall response between the three types (P=0.28). Oedema, erythema, and local induration with fever were the most common adverse effects and were more common in younger children.


Assuntos
Linfangioma , Escleroterapia , Bleomicina , Criança , Humanos , Lactente , Linfangioma/tratamento farmacológico , Linfangioma/terapia , Pescoço , Recidiva Local de Neoplasia , Estudos Prospectivos , Soluções Esclerosantes/uso terapêutico , Resultado do Tratamento
3.
J Appl Microbiol ; 130(5): 1425-1441, 2021 May.
Artigo em Inglês | MEDLINE | ID: mdl-33022786

RESUMO

Human gut microbiome is a diversified, resilient, immuno-stabilized, metabolically active and physiologically essential component of the human body. Scientific explorations have been made to seek in-depth information about human gut microbiome establishment, microbiome functioning, microbiome succession, factors influencing microbial community dynamics and the role of gut microbiome in health and diseases. Extensive investigations have proposed the microbiome therapeutics as a futuristic medicine for various physiological and metabolic disorders. A comprehensive outlook of microbial colonization, host-microbe interactions, microbial adaptation, commensal selection and immuno-survivability is still required to catalogue the essential genetic and physiological features for the commensal engagement. Evolution of a structured human gut microbiome relies on the microbial flexibility towards genetic, immunological and physiological adaptation in the human gut. Key features for commensalism could be utilized in developing tailor-made microbiome-based therapy to overcome various physiological and metabolic disorders. This review describes the key genetics and physiological traits required for host-microbe interaction and successful commensalism to institute a human gut microbiome.


Assuntos
Fenômenos Fisiológicos Bacterianos , Disbiose/terapia , Microbioma Gastrointestinal/fisiologia , Simbiose , Adaptação Fisiológica , Bactérias/genética , Bactérias/imunologia , Microbioma Gastrointestinal/genética , Microbioma Gastrointestinal/imunologia , Interações entre Hospedeiro e Microrganismos , Humanos , Tolerância Imunológica , Redes e Vias Metabólicas , Estresse Fisiológico
4.
Clin Radiol ; 74(9): 735.e9-735.e14, 2019 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-31235284

RESUMO

AIM: To determine the prevalence of the inferior right hepatic vein (IRHV) in patients undergoing routine contrast-enhanced computed tomography (CECT) of the abdomen and to compare it with the size of the right hepatic vein (RHV). MATERIALS AND METHODS: Two hundred and twenty-four consecutive patients who underwent routine CECT abdomen, with adequate venous opacification, were included in the study. The number and diameter of IRHVs and the diameter of the RHV was noted in each case. RESULTS: A total of 214 IRHVs were detected in 126 cases (56.2%) with a mean diameter of 4.15±1.44 mm. The number of IRHVs ranged from one to four (more than one IRHV was present in 39.7% [50/126] of cases). In approximately one-third of cases (46/126), an IRHV ≥5 mm was found. A weak negative correlation was found between size of the RHV and IRHV (Pearson's correlation coefficient -0.222; p=0.01). The RHV was smaller in size in patients with an IRHV (7.34±1.88 mm) than in patients without an IRHV (8.47±1.99 mm) on CECT abdomen. A larger IRHV was associated with a smaller RHV (6.91±2.05 mm). CONCLUSION: The presence of IRHV on routine CECT abdomen is frequent, and it is not uncommon to encounter more than one IRHV. The diameter of the IRHV has a weak negative correlation with the diameter of the RHV, and a smaller RHV is found in patients with an IRHV.


Assuntos
Veias Hepáticas/anatomia & histologia , Veias Hepáticas/diagnóstico por imagem , Tomografia Computadorizada por Raios X/métodos , Adolescente , Adulto , Idoso , Idoso de 80 Anos ou mais , Variação Anatômica , Meios de Contraste , Estudos Transversais , Feminino , Humanos , Iohexol , Masculino , Pessoa de Meia-Idade , Prevalência , Interpretação de Imagem Radiográfica Assistida por Computador
5.
PLoS One ; 12(11): e0187340, 2017.
Artigo em Inglês | MEDLINE | ID: mdl-29131870

RESUMO

In the UK, hospitals with annual platelet use of less than 500 pools, like our institution, usually do not store platelets on-site and these are only ordered from the national blood service (NBS) when a transfusion is required. In 2016, we piloted routine on-site storage of one pool of A RhD negative PLT. Data were collected retrospectively on units of PLTs ordered from NBS, units transfused to patients, wastage, requirements for emergency deliveries from NBS and overall cost. These were compared to corresponding data from the four preceding years (2012-2015). There was a 39% reduction in the PLT ordered from NBS in 2016 compared to previous years and a 50% reduction in transfused PLT. Annual wastage for 2016 increased by 23% even though the absolute number of wasted PLT did not alter significantly. Annual cost reduced by 36% in 2016 resulting from reduction in the total amount of PLTs ordered as well as reduction in emergency deliveries.


Assuntos
Bancos de Sangue , Plaquetas , Preservação de Sangue , Transfusão de Plaquetas/estatística & dados numéricos , Humanos , Estudos Retrospectivos , Reino Unido
6.
Public Health ; 146: 15-23, 2017 May.
Artigo em Inglês | MEDLINE | ID: mdl-28404468

RESUMO

OBJECTIVE: Many blind children in the developing world are unable to obtain timely treatment due to lack of financial and medical resources. Can public health programs that identify and treat such children several years after the onset of blindness enhance their quality of life? The notion that visual development is subject to an early 'critical period' argues against this possibility. However, there are inadequate empirical data from humans on this issue. To address this need, we examined the quality of life of children living in India and who were treated for early-onset blindness (before one year of age), due to cataracts or corneal opacities. STUDY DESIGN: Survey study. METHODS: As part of an ongoing scientific effort named Project Prakash, we screened over 40,000 children in rural northern India to identify those suffering from early-onset blindness. They were provided eye surgeries in a tertiary care ophthalmic center in New Delhi. We subsequently surveyed 64 Prakash children, ranging in age from 5 to 22 years and obtained their responses on a multi-dimensional quality of life questionnaire. RESULTS: Nearly all of the subjects indicated that their quality of life had improved after treatment. Children reported marked enhancement in their mobility, independence, and safety, and also in social integration. Surprisingly, we found no significant correlations between quality of life metrics and factors such as age at treatment, gender, time since treatment, and pre-surgery and post-surgery acuity. CONCLUSIONS: A key question for public health policy makers is whether a program of surgical intervention for older blind children is likely to be beneficial, or if the resources are better spent on rehabilitation via vocational training and assistive devices. The marked improvements in quality of life we find in our data strongly argue for the provision of surgical care regardless of a child's age.


Assuntos
Cegueira/cirurgia , Qualidade de Vida , Adolescente , Idade de Início , Cegueira/etiologia , Catarata/complicações , Criança , Pré-Escolar , Opacidade da Córnea/complicações , Feminino , Humanos , Índia , Masculino , Avaliação de Programas e Projetos de Saúde , População Rural/estatística & dados numéricos , Inquéritos e Questionários , Fatores de Tempo , Adulto Jovem
7.
Indian J Cancer ; 53(1): 143-6, 2016.
Artigo em Inglês | MEDLINE | ID: mdl-27146766

RESUMO

INTRODUCTION: To audit the survival outcomes and loco-regional control in muscle invasive urinary bladder cancer patients treated with external beam radiation therapy (RT). MATERIALS AND METHODS: From November 2008 through December 2011, 50 consecutively diagnosed muscle invasive urinary bladder carcinoma (T2-4a N0-2, M0) patients were included in this retrospective study. All these patients received external beam RT to a median dose of 60 Gy (range 30-66 Gy), and were not suitable for radical surgery due to patients' preference or medical comorbidities. A stepwise procedure using proportional hazard regression was used to identify prognostic factors with respect to survival. RESULTS: Completion trans-urethral resection of bladder tumor was done in 38 (76%) patients of the cohort and 47 (94%) had transitional cell carcinoma on histopathology. Clinical stage T2 was diagnosed in 40 (80%) patients. The median follow-up for the entire cohort was 14 ± 8.9 months (range 1-36 months). In conclusion, 24 patients (48%) were free of disease, 5 patients (10%) had residual disease, and 13 patients (26%) had died of disease. Two-year and 3 year overall survival of intact bladder for the entire cohort was 58% and 43.6%, respectively. Cox regression modeling strongly suggested clinical stage (P = 0.01) and RT dose (P = 0.001) as being predictors for overall survival. CONCLUSION: RT shows reliable outcomes and excellent compliance in this advanced disease. Prescribing a higher RT dose could potentially correlate to better intact bladder control rates while maintaining good quality of life in selected patients.


Assuntos
Neoplasias da Bexiga Urinária/radioterapia , Adulto , Idoso , Idoso de 80 Anos ou mais , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Invasividade Neoplásica , Dosagem Radioterapêutica , Estudos Retrospectivos , Análise de Sobrevida , Resultado do Tratamento , Neoplasias da Bexiga Urinária/mortalidade , Neoplasias da Bexiga Urinária/patologia
8.
Phys Chem Chem Phys ; 18(8): 6191-200, 2016 Feb 17.
Artigo em Inglês | MEDLINE | ID: mdl-26852729

RESUMO

Zintl compounds are potential candidates for efficient thermoelectric materials, because typically they are small band gap semiconductors. In addition, such compounds allow fine tuning of the carrier concentration by chemical doping for the optimization of thermoelectric performance. Herein, such tunability is demonstrated in Mg3Sb2-based Zintl compounds via Zn(2+) doping at the Mg(2+) site of the anionic framework (Mg2Sb2)(2-), in the series Mg3-xZnxSb2 (0 ≤ x ≤ 0.1). The materials have been successfully synthesized using the spark plasma sintering (SPS) technique. X-ray diffraction (XRD) analysis confirms a single solid solution phase of Mg3-xZnxSb2 (0 ≤ x ≤ 0.1). The thermoelectric properties are characterized by the Seebeck coefficient, electrical conductivity, and thermal conductivity measurements from 323 K to 773 K. Isoelectronic Zn substitution at the Mg site presents the controlled variation in the carrier concentration for optimizing the high power factor and reduced thermal conductivity. These results lead to a substantial increase in ZT of 0.37 at 773 K for a composition with x = 0.10 which is ∼42% higher than undoped Mg3Sb2. The electronic transport data for the Mg3-xZnxSb2 (0 ≤ x ≤ 0.1) compound are analyzed using a single parabolic band model predicting that Mg2.9Zn0.1Sb2 exhibits a near-optimal carrier concentration for high ZT. The electronic structure of transport properties of these disordered Mg3-xZnxSb2 (0 ≤ x ≤ 0.1) is also studied using density functional theory and the results obtained are in good agreement with experimental results. The low cost, lightness and non-toxicity of the constituent elements make these materials ideal for mid-temperature thermoelectric applications.

9.
Phys Chem Chem Phys ; 17(44): 30090-101, 2015 Nov 28.
Artigo em Inglês | MEDLINE | ID: mdl-26499748

RESUMO

All scale hierarchical architecturing, matrix/inclusion band alignment and intra-matrix electronic structure engineering, the so called panoscopic approach for thermoelectric materials has been demonstrated to be an effective paradigm for optimizing high ZT. To achieve such hierarchically organized microstructures, composition engineering has been considered to be an efficient strategy. In this work, such a panoscopic concept has been extended to demonstrate for the first time in the case of half-Heusler based thermoelectric materials via a composition engineering route. A series of new off-stoichiometric n-type Zr0.7Hf0.3Ni1+xSn (0 ≤x≤ 0.10) HH compositions have been modified to derive HH(1 -x)/full-Heusler (FH)(x) composite with an all scale hierarchically modified microstructure with FH inclusions within the matrix to study the temperature dependent thermoelectric properties. The structural analysis employing XRD, FE-SEM and HR-TEM of these materials reveal a composite of HH and FH, with hierarchically organized microstructures. In such a submicron/nano-composite, the electronic properties are observed to be well optimized yielding a large power factor; α(2)σ (∼30.7 × 10(-4) W m(-1) K(-2) for Zr0.7Hf0.3Ni1.03Sn) and reduced thermal conductivity (∼2.4 W m(-1) K(-1) for Zr0.7Hf0.3Ni1.03Sn) yielding a high ZT∼ 0.96 at 773 K for composition Zr0.7Hf0.3Ni1.03Sn which is ∼250% larger than the normal HH Zr0.7Hf0.3NiSn (ZT∼ 0.27 at 773 K). The enhancement in ZT of these composites has been discussed in terms of primary electron filtering, electron injection and several phonon scattering mechanisms such as alloy scattering, point defect scattering, and grain boundary scattering. The Bergman and Fel model is used to calculate effective thermoelectric parameters of these composites for comparing the experimental results.

10.
Ultrason Sonochem ; 27: 395-402, 2015 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-26186859

RESUMO

A nickel metal-organic framework (Ni-MOF) was successfully synthesized using ultrasound irradiation. Further to this, X-ray Diffraction (XRD), Scanning Electron Microscopy (SEM), Fourier Transform Infrared Spectroscopy (FT-IR), Thermo-Gravimetric Analysis (TGA), Differential Scanning Calorimetry (DSC) and nitrogen adsorption [i.e. Brunauer-Emmett-Teller (BET) Surface Area Analysis] techniques were used to characterize the synthesized Ni-MOF. In addition, the effect of sonication on the surface area, pore diameter and pore volume of the final product was systematically studied using Taguchi technique. The experiments ascertained that manufacturing of the Ni-MOF by means of the ultrasonic-assisted technique is feasible at a relatively shorter time compare to the conventional methods. The final product showed more uniform shape distribution and improved BET properties. The obtained results offered that the synthesized Ni-MOF samples could be used in several applications.

11.
Mater Sci Eng C Mater Biol Appl ; 50: 117-23, 2015 May.
Artigo em Inglês | MEDLINE | ID: mdl-25746252

RESUMO

In this research, after synthesizing poly(L-lactide-co-ß-malic acid) (PLMA) copolymer, hybrid particles of ice and nanocrystalline forsterite (NF) as coating carriers were used to prepare NF-coated PLMA scaffolds. The porous NF-coated scaffolds were directly fabricated by a combined technique using porogen leaching and freeze-drying methods. The obtained results indicate that the scaffolds were structurally porous with NF particles on their surfaces. When compared to the uncoated scaffolds, the NF coating improved both mechanical properties as well as enhanced bioactivity of the scaffolds. In addition, in vitro biological response of the rat bone marrow stromal cells indicated that NF significantly increased the biocompatibility of NF-coated scaffolds compared with PLMA.


Assuntos
Osso e Ossos/fisiologia , Materiais Revestidos Biocompatíveis/química , Malatos/síntese química , Nanopartículas/química , Poliésteres/síntese química , Compostos de Silício/síntese química , Engenharia Tecidual/métodos , Alicerces Teciduais/química , Animais , Células da Medula Óssea/citologia , Células Cultivadas , Malatos/química , Nanopartículas/ultraestrutura , Tamanho da Partícula , Poliésteres/química , Espectroscopia de Prótons por Ressonância Magnética , Ratos Sprague-Dawley , Compostos de Silício/química , Espectroscopia de Infravermelho com Transformada de Fourier , Células Estromais/citologia , Difração de Raios X
12.
Indian J Pharm Sci ; 76(5): 449-52, 2014 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-25425760

RESUMO

A field experiment on the effect of time of harvesting on yield and quality of Melissa officinalis L. was conducted under the agroclimatic conditions of Doon valley, Uttarakhand in order to assess the performance of four harvesting times (H1-120 days, H2-140 days, H3-160 days and H4-180 days after planting). The fresh and dry herbage and oil yield of the aerial parts showed greater response in H3 i.e. harvesting at 160 days after planting, followed by H2 harvesting time. The quality of essential oil was evaluated using GC and GC-MS analysis. Geranial (24.53 %) and neral (18.80 %) were the major constituents found in the essential oil followed by trans-caryophyllene (7.70 %).

13.
Indian J Pharm Sci ; 76(1): 72-7, 2014 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-24799741

RESUMO

The present study was aimed to investigate the role of plasma glucose concentration as a phenotypic marker and to study the frequency distribution of CYP2C9 genetic variants in Gujarat state diabetic population. One hundred and nine unrelated diabetes mellitus patients treated with sulfonylureas were genotyped for CYP2C9*2 and CYP2C9*3 alleles. Their pre- and posttreatment postprandial blood glucose levels were recorded and mean glucose drop per milligram of drug values were calculated and further used as an index for phenotypic correlation. The frequencies of CYP2C9*1, CYP2C9*2 and CYP2C9*3 alleles in the Gujarat state diabetic population were 0.84, 0.07 and 0.09, respectively. The distribution of CYP2C9*1/*1, CYP2C9*1/*2, CYP2C9*1/*3, CYP2C9*2/*2, CYP2C9*2/*3 and CYP2C9*3/*3 genotypes were 0.73, 0.08, 0.13, 0.0, 0.06 and 0.0, respectively. Patients with CYP2C9*1/*2 genotype did not show any significant difference in the mean glucose drop per milligram of drug values when compared with wild-type patients in glipizide-treatment group. Patients with CYP2C9*1/*3 genotype showed greater mean glucose drop per milligram of drug values than patients with CYP2C9*1/*1 wild-type genotype for both glipizide and glimepiride while patients with CYP2C9*2/*3 genotype showed greater drop than patients with CYP2C9*1/*1 genotype only in the glipizide-treatment group. The presence of CYP2C9*3 allele significantly affected plasma glucose drop per milligram of drug values in patients taking glipizide and glimepiride, while effects of CYP2C9*2 allele were insignificant. Further studies are needed to confirm the effects of CYP2C9*2 allele on plasma glucose drop per milligram of drug values. However, plasma glucose concentration is a complex physiological marker that cannot be used to establish perfect genotype-phenotype correlation. Hence studies exploring robust phenotypic markers must be initiated.

14.
Gulf J Oncolog ; 1(15): 56-62, 2014 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-24610289

RESUMO

INTRODUCTION: To report on prognostic and treatment factors influencing the response of SVCO and related survival outcomes in advanced non small cell lung cancer. MATERIAL AND METHODS: From November 2008 through December 2011, 18 consecutively diagnosed NSCLC patients with SVCO were included in this study. The patient, tumor and treatment related factors were analyzed. Median overall survival (OS), Kaplan -Meier survival plots, T-test, Cox Proportional Hazards models were generated by multiple covariates (MVA) and analyzed on SPSS software (version 19.0; SPSS, Inc., Chicago, IL). RESULTS: Thirteen patients (72%) had presented with SVCO before the pathological diagnosis of underlying lung malignancy, while 5 (28%) progressed to SVCO after initiating treatment with chemotherapy. Twelve (68%) patients achieved subjective relief from the obstruction at the completion of palliative radiation therapy. Treating oncologists preferred 4 Gy per fraction in 11 (62%), while the median biologically equivalent dose delivered was 28 Gy. Six (33%) patients received chemotherapy during the course of treatment. Median OS of the entire cohort was 3±1.85mths and 1-year survival rate of 7%. Univariate analysis confirmed that SVCO patients with good performance score (p=0.02), and partial response to chemotherapy (p= 0.001) have superior OS. However, Cox regression modeling for MVA demonstrated only good performance SVCO patients (p = 0.05) have a better OS. CONCLUSION: RT effectively relieves SVCO but overall poor survival associated in our clinical scenario needs to be improved with multimodality approach. Adjuvant chemotherapy is to be considered after initial radiation therapy in good performance patients. KEYWORDS: superior vena cava obstruction (SVCO), radiation therapy, chemotherapy, non small cell lung cancer (NSCLC), BED (biologically equivalent dose).

15.
Indian J Pharm Sci ; 75(4): 489-93, 2013 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-24302806

RESUMO

A field experiment was conducted under the agroclimatic conditions of Doon valley, in order to determine the effects of phenological stages on herbage yield and quality of oil in oregano (Origanum vulgare L.). Plants were harvested in five phenological stages, i.e. early vegetative, late vegetative, flower initiation, full bloom, and fruit set stages. Results showed the significant effects of phenological stages on herbage, yield, and quality of oregano. Harvesting at full bloom stage showed better results in terms of herbage and oil yield. The quality of essential oil was evaluated using GC and GC/MS. Thymol content was rich in all the stages (46.90-62.26%) followed by γ-terpinene (1.11-11.75%) and p-cymene (3.11-5.32%).

16.
Scott Med J ; 58(2): e13-7, 2013 May.
Artigo em Inglês | MEDLINE | ID: mdl-23728764

RESUMO

INTRODUCTION: It is rare to see heart block as the first-and-only presentation of Lyme disease, the reported incidence being just 1% in untreated patients. CASE PRESENTATION: We report a patient who presented with syncope secondary to a fluctuating heart block. He had no previous manifestations of Lyme disease. Lyme carditis was suspected after the other usual etiologies of heart block were ruled out. Later, serologies came positive and patient's heart block resolved on ceftriaxone therapy. CONCLUSION: In at-risk individuals, clinicians should rule out this readily-treatable cause of heart block before proceeding with permanent pacemaker implantation due to enormous clinical and cost implications involved. Missing the diagnosis also exposes the patient to the risk of developing the late complications of Lyme disease. Diagnosis of isolated Lyme carditis is a challenge because the clinician does not have the diagnostic-clues that can usually be gleaned from the more common stigmata of Lyme disease.


Assuntos
Bloqueio Cardíaco/etiologia , Doença de Lyme/diagnóstico , Miocardite/etiologia , Antibacterianos/uso terapêutico , Humanos , Doença de Lyme/complicações , Doença de Lyme/tratamento farmacológico , Masculino , Pessoa de Meia-Idade , Miocardite/diagnóstico , Síncope/etiologia
17.
Int J Biol Macromol ; 60: 45-51, 2013 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-23707748

RESUMO

A method is described for construction of an amperometric triglyceride (TG) biosensor based on co-immobilization of lipase, glycerol kinase (GK) and glycerol-3-phosphate oxidase (GPO) onto nickel oxide nanoparticles (NiONPs)-chitosan (CHIT) nanocomposite adsorbed onto zinc oxide/zinc hexacyanoferrate (ZnO-ZnHCF) hybrid film electrodeposited on the surface of an Au electrode. The NiONPs-CHIT/ZnO-ZnHCF hybrid film was characterized by cyclic voltammetry (CV), atomic force microscopy (AFM) and electrochemical impedance spectroscopy (EIS). The biosensor showed optimum response within 4 s at pH 6.0 and 35 °C, when polarized at +0.4 V against Ag/AgCl. There was a linear relationship between sensor response and triolein concentration in the range 50-700 mg/dl with sensitivity of 0.05 µA/mg/dl. The sensor was employed for determination of TG in serum. The detection limit of the biosensor was 10 mg/dl. The biosensor was evaluated with 95-96% recovery of added triolein in sera and 2% and 3% within and between batch coefficients of variation (CVs) respectively. There was a good correlation (r=0.99) between serum TG values by standard enzymic colorimetric method and the present method. The biosensor lost 50% of its initial activity after its 100 uses over a period of 180 days, when stored at 4 °C.


Assuntos
Técnicas Biossensoriais , Quitosana/química , Níquel/química , Óxido de Zinco/química , Eletrodos
18.
Enzyme Microb Technol ; 52(4-5): 265-71, 2013 Apr 10.
Artigo em Inglês | MEDLINE | ID: mdl-23540929

RESUMO

A commercial lysine oxidase (LyOx) from Trichoderma viride was immobilized covalently onto gold nanoparticles (AuNPs) and platinum nanoparticles (PtNPs) electrodeposited onto Au electrode using 3-aminopropyltriethoxy silane (3-APTES) and glutaraldehyde cross linking chemistry. A lysine biosensor was fabricated using LyOx/3-APTES/AuNPs-PtNPs/Au electrode as a working electrode, Ag/AgCl (3M KCl) as standard electrode and Pt wire as auxiliary electrode connected through a potentiostat. The enzyme electrode was characterized by scanning electron microscopy (SEM), Fourier transform infrared (FTIR) spectroscopy, electrochemical impedance spectroscopy (EIS) and cyclic voltammetry (CV). The cumulative effect of AuNPs and PtNPs showed excellent electrocatalytic activity at low applied potential for detection of H2O2, a product of LyOx reaction. The sensor showed its optimum response within 4s, when polarized at 0.2V vs. Ag/AgCl in 0.1M phosphate buffer, pH 7.5 at 30°C. The linear range and detection limit of the sensor were 1.0-600µM and 1.0µM (S/N=3), respectively. Biosensor measured lysine level in sera, milk and amino acid tablet, which correlated well with those by standard HPLC method. The enzyme electrode lost 50% of its initial activity after 200 uses over a period of 4 months.


Assuntos
Aminoácido Oxirredutases/metabolismo , Técnicas Biossensoriais/métodos , Lisina/análise , Adulto , Animais , Espectroscopia Dielétrica , Técnicas Eletroquímicas , Estabilidade Enzimática , Enzimas Imobilizadas/metabolismo , Feminino , Ouro , Humanos , Lisina/sangue , Masculino , Nanopartículas Metálicas/ultraestrutura , Microscopia Eletrônica de Varredura , Leite/química , Platina , Espectroscopia de Infravermelho com Transformada de Fourier
19.
Anal Biochem ; 427(1): 26-32, 2012 Aug 01.
Artigo em Inglês | MEDLINE | ID: mdl-22561918

RESUMO

A bienzymatic choline biosensor was constructed by coimmobilizing acetylcholinesterase (AChE) and choline oxidase (ChO) onto nanocomposite of carboxylated multiwalled carbon nanotubes (c-MWCNTs) and zirconium oxide nanoparticles (ZrO(2)NPs) electrodeposited on the surface of a glassy carbon electrode (GCE) and using it (AChE-ChO/c-MWCNT/ZrO(2)NPs/GCE) as working electrode, Ag/AgCl as reference electrode, and Pt wire as auxiliary electrode connected through a potentiostat. The enzyme electrode was characterized by scanning electron microscopy (SEM), Fourier transform infrared (FTIR) spectroscopy, and cyclic voltammetry (CV) studies, optimized, and evaluated. The biosensor exhibited optimum response within 4 s at +0.2V, pH 7.4, and 25 °C. The detection limit and working range of the biosensor were 0.01 µM and 0.05 to 200 µM, respectively. The half-life of the enzyme electrode was 60 days at 4 °C. The serum choline level, as measured by the biosensor, was 9.0 to 12.8 µmol/L (with a mean of 10.81 µmol/L) in apparently healthy persons and 5.0 to 8.4 µmol/L (with a mean of 6.53 µmol/L) in persons suffering from Alzheimer's disease. The enzyme electrode was unaffected by a number of serum substances.


Assuntos
Acetilcolinesterase/química , Oxirredutases do Álcool/química , Doença de Alzheimer/sangue , Colina/sangue , Técnicas Eletroquímicas , Adolescente , Adulto , Técnicas Biossensoriais , Criança , Pré-Escolar , Eletrodos , Enzimas Imobilizadas/química , Feminino , Humanos , Lactente , Limite de Detecção , Masculino , Pessoa de Meia-Idade , Nanopartículas/química , Nanotubos de Carbono/química , Zircônio/química
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