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2.
Front Plant Sci ; 14: 1265925, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-37860255

RESUMO

Increasing attention is paid to providing new tools to breeders for targeted breeding for specific root traits that are beneficial in low-fertility, drying soils; however, such information is not available for barley (Hordeum vulgare L.). A panel of 191 barley accessions (originating from Australia, Europe, and Africa) was phenotyped for 26 root and shoot traits using the semi-hydroponic system and genotyped using 21 062 high-quality single nucleotide polymorphism (SNP) markers generated by genotyping-by-sequencing (GBS). The population structure analysis of the barley panel identified six distinct groups. We detected 1199 significant (P<0.001) marker-trait associations (MTAs) with r2 values up to 0.41. The strongest MTAs were found for root diameter in the top 20 cm and the longest root length. Based on the physical locations of these MTAs in the barley reference genome, we identified 37 putative QTLs for the root traits, and three QTLs for shoot traits, with nine QTLs located in the same physical regions. The genomic region 640-653 Mb on chromosome 7H was significant for five root length-related traits, where 440 annotated genes were located. The putative QTLs for various root traits identified in this study may be useful for genetic improvement regarding the adaptation of new barley cultivars to suboptimal environments and abiotic stresses.

3.
Nat Commun ; 14(1): 6036, 2023 09 27.
Artigo em Inglês | MEDLINE | ID: mdl-37758713

RESUMO

Hydrogen peroxide (H2O2) functions as a second messenger to signal metabolic distress through highly compartmentalized production in mitochondria. The dynamics of reactive oxygen species (ROS) generation and diffusion between mitochondrial compartments and into the cytosol govern oxidative stress responses and pathology, though these processes remain poorly understood. Here, we couple the H2O2 biosensor, HyPer7, with optogenetic stimulation of the ROS-generating protein KillerRed targeted into multiple mitochondrial microdomains. Single mitochondrial photogeneration of H2O2 demonstrates the spatiotemporal dynamics of ROS diffusion and transient hyperfusion of mitochondria due to ROS. This transient hyperfusion phenotype required mitochondrial fusion but not fission machinery. Measurement of microdomain-specific H2O2 diffusion kinetics reveals directionally selective diffusion through mitochondrial microdomains. All-optical generation and detection of physiologically-relevant concentrations of H2O2 between mitochondrial compartments provide a map of mitochondrial H2O2 diffusion dynamics in situ as a framework to understand the role of ROS in health and disease.


Assuntos
Peróxido de Hidrogênio , Mitocôndrias , Espécies Reativas de Oxigênio/metabolismo , Peróxido de Hidrogênio/metabolismo , Mitocôndrias/metabolismo , Estresse Oxidativo , Sistemas do Segundo Mensageiro
5.
Insects ; 13(11)2022 Nov 09.
Artigo em Inglês | MEDLINE | ID: mdl-36354861

RESUMO

The research was focused on the ability of wheat aphids Sitobion avenae, harboring bacterial secondary symbionts (BSS) Hamiltonella defensa or Regiella insecticola, to withstand exposure to fungal isolates of Beauveria bassiana and Metarhizium brunneum. In comparison to aphids lacking bacterial secondary symbionts, BSS considerably increased the lifespan of wheat aphids exposed to B. bassiana strains (Bb1022, EABb04/01-Tip) and M. brunneum strains (ART 2825 and BIPESCO 5) and also reduced the aphids' mortality. The wheat aphid clones lacking bacterial secondary symbionts were shown to be particularly vulnerable to M. brunneum strain BIPESCO 5. As opposed to wheat aphids carrying bacterial symbionts, fungal pathogens infected the wheat aphids lacking H. defensa and R. insecticola more quickly. When treated with fungal pathogens, bacterial endosymbionts had a favorable effect on the fecundity of their host aphids compared to the aphids lacking these symbionts, but there was no change in fungal sporulation on the deceased aphids. By defending their insect hosts against natural enemies, BSS increase the population of their host society and may have a significant impact on the development of their hosts.

6.
Nat Commun ; 13(1): 2403, 2022 05 03.
Artigo em Inglês | MEDLINE | ID: mdl-35504873

RESUMO

C. elegans react to metabolic distress caused by mismatches in oxygen and energy status via distinct behavioral responses. At the molecular level, these responses are coordinated by under-characterized, redox-sensitive processes, thought to initiate in mitochondria. Complex I of the electron transport chain is a major site of reactive oxygen species (ROS) production and is canonically associated with oxidative damage following hypoxic exposure. Here, we use a combination of optogenetics and CRISPR/Cas9-mediated genome editing to exert spatiotemporal control over ROS production. We demonstrate a photo-locomotory remodeling of avoidance behavior by local ROS production due to the reversible oxidation of a single thiol on the complex I subunit NDUF-2.1. Reversible thiol oxidation at this site is necessary and sufficient for the behavioral response to hypoxia, does not respond to ROS produced at more distal sites, and protects against lethal hypoxic exposure. Molecular modeling suggests that oxidation at this thiol residue alters the ability for NDUF-2.1 to coordinate electron transfer to coenzyme Q by destabilizing the Q-binding pocket, causing decreased complex I activity. Overall, site-specific ROS production regulates behavioral responses and these findings provide a mechanistic target to suppress the detrimental effects of hypoxia.


Assuntos
Caenorhabditis elegans , Compostos de Sulfidrila , Animais , Aprendizagem da Esquiva , Caenorhabditis elegans/genética , Caenorhabditis elegans/metabolismo , Complexo I de Transporte de Elétrons/genética , Complexo I de Transporte de Elétrons/metabolismo , Hipóxia , Espécies Reativas de Oxigênio/metabolismo
7.
BMJ Open Respir Res ; 9(1)2022 03.
Artigo em Inglês | MEDLINE | ID: mdl-35273027

RESUMO

INTRODUCTION: To examine the prevalence of chronic obstructive pulmonary disease (COPD) misclassification and the associated burden of symptoms, healthcare utilisation and physical performance status in the Canadian general population. This information is presently lacking from large population-based studies with high-quality spirometry data that can be generalised to the general population. METHODS: The prevalence of self-reported physician-diagnosed COPD and the concordance with spirometry airflow obstruction (AO) were assessed in a cross-sectional cohort of Canadian older adults. The associations between confirmed COPD, under-diagnosis and over-diagnosis with self-reported respiratory symptoms, healthcare utilisation and physical performance (timed up and go, handgrip strength and 4 metres walk test) were assessed, adjusting for baseline characteristics using multivariable linear and logistic models. RESULTS: A total of 21 242 participants (mean age 64 (SD 10) years; 42% men) with high quality spirometry were included. Physician-diagnosed COPD was reported in (n=973) 5% of the participants. Only (n=217) 1% of the entire cohort had confirmed COPD supported by spirometry AO. Discordance between self-reported COPD and spirometry findings was observed in (n=1565) 8%: with 4% representing under-diagnosis cases (no self-reported COPD but AO) and 4% representing over-diagnosis cases (self-reported COPD but no AO). Compared with normals (no self-reported COPD and normal spirometry), those with confirmed, under-diagnosed or over-diagnosed COPD showed higher risks for respiratory symptoms (adjusted OR (aOR) 2.1 (95% CI: 1.6 to 2.7); aOR 1.8 (95% CI: 1.6 to 2.1]; aOR 1.6 (95% CI: 1.4 to 1.9)); healthcare utilisation in the prior 12 months (ß coefficient 0.8 (95% CI: 0.2 to 2.6); ß 0.9 (95% CI: 0.5 to 1.5); ß 1.6 (95% CI: 0.7 to 4.0)). Mood disorders were higher in confirmed and over-diagnosed COPD (aOR 1.7 (95% CI: 1.3 to 2.4); 1.7 (95% CI: 1.4 to 2.0), respectively). Physical performance was lower for COPD groups. CONCLUSIONS: The prevalence of COPD misclassification is high in the general population of older adults. These were associated with significantly high burden of respiratory symptoms, healthcare utilisation and low physical performance compared with the general population with normal spirometry and no self-reported COPD. These findings highlight the high burden of COPD misclassification, which may be substantially reduced with greater accessibility to spirometry measurements in the community.


Assuntos
Força da Mão , Doença Pulmonar Obstrutiva Crônica , Idoso , Envelhecimento , Canadá/epidemiologia , Estudos Transversais , Feminino , Humanos , Estudos Longitudinais , Masculino , Pessoa de Meia-Idade , Prevalência , Doença Pulmonar Obstrutiva Crônica/diagnóstico , Doença Pulmonar Obstrutiva Crônica/epidemiologia
8.
Eur Respir J ; 60(4)2022 10.
Artigo em Inglês | MEDLINE | ID: mdl-35273032

RESUMO

BACKGROUND: Progressive fibrosing interstitial lung disease (PF-ILD) is characterised by progressive physiological, symptomatic and/or radiographic worsening. The real-world prevalence and characteristics of PF-ILD remain uncertain. METHODS: Patients were enrolled from the Canadian Registry for Pulmonary Fibrosis between 2015 and 2020. PF-ILD was defined as a relative forced vital capacity (FVC) decline ≥10%, death, lung transplantation or any two of: relative FVC decline ≥5% and <10%, worsening respiratory symptoms or worsening fibrosis on computed tomography of the chest, all within 24 months of diagnosis. Time-to-event analysis compared progression between key diagnostic subgroups. Characteristics associated with progression were determined by multivariable regression. RESULTS: Of 2746 patients with fibrotic ILD (mean±sd age 65±12 years; 51% female), 1376 (50%) met PF-ILD criteria in the first 24 months of follow-up. PF-ILD occurred in 427 (59%) patients with idiopathic pulmonary fibrosis (IPF), 125 (58%) with fibrotic hypersensitivity pneumonitis (HP), 281 (51%) with unclassifiable ILD (U-ILD) and 402 (45%) with connective tissue disease-associated ILD (CTD-ILD). Compared with IPF, time to progression was similar in patients with HP (hazard ratio (HR) 0.96, 95% CI 0.79-1.17), but was delayed in patients with U-ILD (HR 0.82, 95% CI 0.71-0.96) and CTD-ILD (HR 0.65, 95% CI 0.56-0.74). Background treatment varied across diagnostic subtypes, with 66% of IPF patients receiving antifibrotic therapy, while immunomodulatory therapy was utilised in 49%, 61% and 37% of patients with CHP, CTD-ILD and U-ILD, respectively. Increasing age, male sex, gastro-oesophageal reflux disease and lower baseline pulmonary function were independently associated with progression. CONCLUSIONS: Progression is common in patients with fibrotic ILD, and is similarly prevalent in HP and IPF. Routinely collected variables help identify patients at risk for progression and may guide therapeutic strategies.


Assuntos
Alveolite Alérgica Extrínseca , Fibrose Pulmonar Idiopática , Doenças Pulmonares Intersticiais , Idoso , Alveolite Alérgica Extrínseca/complicações , Alveolite Alérgica Extrínseca/epidemiologia , Canadá/epidemiologia , Progressão da Doença , Feminino , Humanos , Fibrose Pulmonar Idiopática/complicações , Fibrose Pulmonar Idiopática/diagnóstico , Fibrose Pulmonar Idiopática/epidemiologia , Doenças Pulmonares Intersticiais/complicações , Doenças Pulmonares Intersticiais/diagnóstico , Doenças Pulmonares Intersticiais/epidemiologia , Masculino , Pessoa de Meia-Idade , Prevalência , Sistema de Registros
9.
Front Genet ; 12: 780599, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-35198001

RESUMO

Rice is an important staple food grain consumed by most of the population around the world. With climate and environmental changes, rice has undergone a tremendous stress state which has impacted crop production and productivity. Plant growth hormones are essential component that controls the overall outcome of the growth and development of the plant. Cytokinin is a hormone that plays an important role in plant immunity and defense systems. Trans-zeatin is an active form of cytokinin that can affect plant growth which is mediated by a multi-step two-component phosphorelay system that has different roles in various developmental stages. Systems biology is an approach for pathway analysis to trans-zeatin treated rice that could provide a deep understanding of different molecules associated with them. In this study, we have used a weighted gene co-expression network analysis method to identify the functional modules and hub genes involved in the cytokinin pathway. We have identified nine functional modules comprising of different hub genes which contribute to the cytokinin signaling route. The biological significance of these identified hub genes has been tested by applying well-proven statistical techniques to establish the association with the experimentally validated QTLs and annotated by the DAVID server. The establishment of key genes in different pathways has been confirmed. These results will be useful to design new stress-resistant cultivars which can provide sustainable yield in stress-specific conditions.

10.
Comput Methods Programs Biomed ; 184: 105124, 2020 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-31627149

RESUMO

BACKGROUND AND OBJECTIVE: Non-invasive treatment of unruptured Abdominal Aortic Aneurysm involves subjecting the patients to certain physiological levels of the heart. Flow topology (Repeak = 200-1200, frequency: f = 1.18-2.41 Hz) within an aneurysm geometry (2-D) under resting and exercise (mild and moderate) conditions are explored in the present study. Blood is assumed to be Newtonian in nature. Spatio-temporal evolution of the flow patterns and vorticity are established. Hemodynamic indicators (TAWSS and OSI), movement of vortex cores and Particle Residence Index (PRI) are quantified to select an optimum exercise level in attenuating the disease. METHODS: The finite volume method is employed for numerical solutions using ANSYS-FluentⓇ software. The SIMPLE scheme has been used for the pressure-velocity coupling. Least Square cell-based method is used for the spatial discretization of the gradients. Second order upwind scheme is considered for discretization of the pressure term. Third order upwind (QUICK) scheme is used to discretize the momentum equation. First order Implicit Scheme was used for the discretization of the temporal terms. Discrete Phase Material (DPM) technique is employed throughout, to visualize the signature of particle deposits within the aneurysm. RESULTS: Vortex impingement induces a pressure peak within the aneurysm (moderate) while the peaks are anchored at the proximal and distal ends under resting and mild conditions. Along the averaged flow separation zone, exercise increases the maximum TAWSS from 1.21 N/m2 (mild) to 9.3 N/m2 (moderate). The distal site is exposed to oscillatory loading (OSI = 0.5) under mild activity whereas the loading becomes distributed almost over the entire wall, when subjected to moderate conditions. This in turn, reduces the time involved in 50 percent clearance of particles (PRI = 0.5) from 10.56 s (resting) to 3.98 s (mild) and 0.87 s (moderate), respectively. CONCLUSIONS: Resting conditions manifests the aneurysmal wall to recirculating fluid for most of cycle time. Moderate exercise exhibits the least particle clearance time, but it exposes the aneurysmal wall and the distal end to high pressure, which otherwise has low intensity under mild activity. This in turn establishes that mild exercise for prolonged duration can be an optimum level for non-invasive aneurysmal treatment.


Assuntos
Aneurisma da Aorta Abdominal/fisiopatologia , Exercício Físico , Hemodinâmica , Velocidade do Fluxo Sanguíneo , Progressão da Doença , Análise de Elementos Finitos , Humanos
11.
PLoS One ; 12(1): e0169949, 2017.
Artigo em Inglês | MEDLINE | ID: mdl-28099445

RESUMO

BACKGROUND: The prevalence rate of type 2 diabetes mellitus (T2DM) is one of the highest in United Arab Emirates (UAE), however data for the expatriate population is limited. This study aimed to identify the prevalence of T2DM amongst migrant women and test the hypothesis that acculturation (measured by years of residency) is associated with an increased risk of T2DM. METHODS: This was a cross-sectional study and we recruited a representative sample (n = 599, 75% participation rate) of migrant women aged 18 years and over in Al Ain, UAE. The American Diabetes Association criteria were used to diagnose T2DM. An adapted WHO STEPS questionnaire was used to collect socio-demographic, lifestyle and clinical data. Logistic regression analysis was performed to identify correlates of T2DM including length of UAE residence. RESULTS: The mean age of participants was 34.1 (± 9.5) years. Of the study participants, based on HbA1C levels, 18.6% (95% CI: 13.9-24.4) had prediabetes and 10.7% (95% CI: 7.2-15.6) had T2DM. Prevalence of prediabetes was 8.5% for Filipinos, 16.7% for Arabs and 30.3% for South Asians. Similarly the prevalence of T2DM was 1.7% for Filipinos, 12.2% for Arabs and 16.7% for South Asians. Significant correlates of overall T2DM (measured and known diabetes) included length of UAE residence for more than 10 years (Adjusted Odds Ratio [AOR] 2.74, 95% CI: 1.21-6.20), age ≥40 years (AOR = 3.48, 95% CI: 1.53-7.87) and South Asian nationality (AOR 2.10, 95% CI: 0.94-4.70). CONCLUSION: Diabetes is a significant public health problem among migrant women in the UAE, particularly for South Asians. Longer length of residence in the UAE is associated with a higher prevalence of diabetes.


Assuntos
Diabetes Mellitus Tipo 2/epidemiologia , Migrantes/estatística & dados numéricos , Adulto , Sudeste Asiático , Índice de Massa Corporal , Estudos Transversais , Feminino , Humanos , Filipinas , Fatores Socioeconômicos , Emirados Árabes Unidos/epidemiologia
12.
Genet Mol Res ; 15(4)2016 Dec 19.
Artigo em Inglês | MEDLINE | ID: mdl-28002609

RESUMO

In this study, eight inbred maize lines with high or low tolerance to cold temperature were investigated using bulk segregant analysis (BSA). Genetic diversity and genetic relationships were investigated using 100 simple sequence repeat (SSR) markers linked to cold tolerance in maize. A total of 319 alleles were identified. Among these, 128 were high coldtolerant-specific alleles and 61 were poorly coldtolerant-specific alleles, while the remaining 130 were shared between the two types. The number of alleles per locus ranged from 2 to 5, with an average of 3.19. The major allele frequency varied from 0.39 to 0.53 with an average of 0.47. The average gene diversity and polymorphic information content among all lines were 0.63 and 0.58, respectively. A dendrogram analysis identified three main clusters and most of the high tolerant inbred lines were clearly distinguished from the poorly tolerant inbred lines. In addition to the BSA, a total of 84 SSR markers were identified as high cold tolerance-specific alleles and 52 SSRs were detected as poorly cold tolerance-specific alleles. Of these, bnlg1273, umc1124, dupssr21, mmc0251, mmc0181, and phi041 have great potential for being molecular markers for cold tolerance in maize. Our results were in agreement with results previously reported for SSR markers linked with cold tolerance in maize. The identification and characterization of high and poorly cold tolerant maize lines based on SSR markers will be useful for future maize breeding studies.


Assuntos
Repetições de Microssatélites , Zea mays/crescimento & desenvolvimento , Zea mays/genética , Análise por Conglomerados , Temperatura Baixa , DNA de Plantas/genética , Marcadores Genéticos/genética , Polimorfismo Genético , Estresse Fisiológico
14.
J Coll Physicians Surg Pak ; 15(10): 638-41, 2005 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-19810305

RESUMO

OBJECTIVE: To determine the outcome of patients undergoing extracorporeal shock wave lithotripsy (ESWL) for treatment of upper urinary tract calculi (renal and ureteric), and to note role of double-J (DJ) stents in these patients. DESIGN: A cross-sectional analytical study. PLACE AND DURATION OF STUDY: Department of Urology, Rawalpindi General Hospital, Rawalpindi, from February 1999 to July 2001. PATIENTS AND METHODS: Record of patients who underwent ESWL for renal and ureteric stones was retrieved and analyzed using statistical program, SPSS version-10 and Epi-Info 2000. In some patients pre-ESWL DJ stents were placed because of various reasons like solitary kidney, large stone volume etc. Patients were divided in two groups, Group I, in whom DJ stents were not placed, and Group II, in whom DJ stents were placed. ESWL was performed in each subject in standard way employing piezoelectric lithotripter E.D.A.P. LT 02X. Patients were evaluated for stone clearance fortnightly with X-ray or ultrasound. RESULTS: Four hundred and thirty-two patients, 68.8% male and 31.2% female, underwent ESWL. Mean age of patients was 37.7 +/- 13.1 years. Majority of patients (78.47%, n = 339) had renal, while rest had ureteric stones. Group I and II included 408 (94.4%) and 24 (5.6%) patients respectively. Renal stones were present in 78% (n=318) of Group I and 87.5% [n = 21] of Group II patients. Mean size of stones in Group I and II patients was 10.91 +/- 4.6, and 10.4 +/- 4.7mm. Stone clearance was 96.3% and 100% in Group I and Group II patients respectively. Significantly more ESWL sessions were required for stone clearance in Group II (p-value 0.03); in addition Group II patients had significantly more complications (p-value 0.01). CONCLUSION: ESWL is an effective procedure. Pre-ESWL stenting is associated with increased numbers of ESWL sessions and more complications.


Assuntos
Cálculos Renais/terapia , Litotripsia , Cálculos Ureterais/terapia , Adulto , Feminino , Humanos , Litotripsia/efeitos adversos , Masculino , Pessoa de Meia-Idade , Retratamento , Stents , Adulto Jovem
15.
Diabetes Care ; 27(1): 168-72, 2004 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-14693984

RESUMO

OBJECTIVE: Diabetic peripheral neuropathy (DPN) has been thought to be progressive and irreversible. Recently, symptomatic reversal of DPN was reported after treatments with a near-infrared medical device, the Anodyne Therapy System (ATS). However, the study was not controlled nor was the investigator blinded. We initiated this study to determine whether treatments with the ATS would decrease pain and/or improve sensation diminished due to DPN under a sham-controlled, double-blind protocol. RESEARCH DESIGN AND METHODS: Tests involved the use of the 5.07 and 6.65 Semmes Weinstein monofilament (SWM) and a modified Michigan Neuropathy Screening Instrument (MNSI). Twenty-seven patients, nine of whom were insensitive to the 6.65 SWM and 18 who were sensitive to this filament but insensitive to the 5.07 SWM, were studied. Each lower extremity was treated for 2 weeks with sham or active ATS, and then both received active treatments for an additional 2 weeks. RESULTS: The group of 18 patients who could sense the 6.65 SWM but were insensitive to the 5.07 SWM at baseline obtained a significant decrease in the number of sites insensate after both 6 and 12 active treatments (P < 0.02 and 0.001). Sham treatments did not improve sensitivity to the SWM, but subsequent active treatments did (P < 0.002). The MNSI measures of neuropathic symptoms decreased significantly (from 4.7 to 3.1; P < 0.001). Pain reported on the 10-point visual analog scale decreased progressively from 4.2 at entry to 3.2 after 6 treatments and to 2.3 after 12 treatments (both P < 0.03). At entry, 90% of subjects reported substantial balance impairment; after treatment, this decreased to 17%. However, among the group of nine patients with greater sensory impairment measured by insensitivity to the 6.65 SWM at baseline, improvements in sensation, neuropathic symptoms, and pain reduction were not significant. CONCLUSIONS: ATS treatments improve sensation in the feet of subjects with DPN, improve balance, and reduce pain.


Assuntos
Neuropatias Diabéticas/terapia , Dor/prevenção & controle , Equilíbrio Postural/fisiologia , Idoso , Idoso de 80 Anos ou mais , Analgésicos/uso terapêutico , Método Duplo-Cego , Feminino , , Humanos , Masculino , Pessoa de Meia-Idade , Medição da Dor , Placebos
16.
Pharm Dev Technol ; 6(2): 247-54, 2001.
Artigo em Inglês | MEDLINE | ID: mdl-11416999

RESUMO

A new commercially available sustained-release matrix material, Kollidon SR, composed of polyvinylacetate and povidone, was evaluated with respect to its ability to modulate the in vitro release of a highly water-soluble model compound, diphenhydramine HCl. Kollidon SR was found to provide a sustained-release effect for the model compound, with certain formulation and processing variables playing an important role in controlling its release kinetics. Formulation variables affecting the release include the level of the polymeric material in the matrix, excipient level, as well as the nature of the excipients (water soluble vs. water insoluble). Increasing the ratio of a water-insoluble excipient, Emcompress, to Kollidon SR enhanced drug release. The incorporation of a water-soluble excipient, lactose, accelerated its release rate in a more pronounced manner. Stability studies conducted at 40 degrees C/75% RH revealed a slow-down in dissolution rate for the drug-Kollidon SR formulation, as a result of polyvinylacetate relaxation. Further studies demonstrated that a post-compression curing step effectively stabilized the release pattern of formulations containing > or = 47% Kollidon SR. The release mechanism of Kollidon-drug and drug-Kollidon-Emcompress formulations appears to be diffusion controlled, while that of the drug-Kollidon-lactose formulation appears to be controlled predominantly by diffusion along with erosion.


Assuntos
Difenidramina/administração & dosagem , Polivinil/administração & dosagem , Povidona/administração & dosagem , Química Farmacêutica , Preparações de Ação Retardada , Solubilidade , Comprimidos
17.
Appl Microbiol Biotechnol ; 52(3): 373-9, 1999 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-10531650

RESUMO

A general procedure for the high yield immobilization of enzymes with the help of specific anti-enzyme antibodies is described. Polyclonal antibodies were raised against Aspergillus niger glucose oxidase and horseradish peroxidase in rabbits and the gamma globulin (IgG) fraction from the immune sera isolated by ammonium sulphate fractionation followed by ion-exchange chromatography. Immobilization of glucose oxidase and horseradish peroxidase was achieved by initially binding the enzymes to a Sepharose matrix coupled with IgG isolated from anti-(glucose oxidase) and anti-(horseradish peroxidase) sera, respectively. This was followed by alternate incubation with the IgG and the enzyme to assemble layers of enzyme and antibody on the support. The immunoaffinity-layered preparations obtained thus were highly active and, after six binding cycles, the amount of enzyme immobilized could be raised about 25 times over that bound initially. It was also possible to assemble layers of glucose oxidase using unfractionated antiserum in place of the IgG. The bioaffinity-layered preparations of glucose oxidase and horseradish peroxidase exhibited good enzyme activities and improved resistance to heat-induced inactivation. The sensitivity of a flow injection analysis system for measuring glucose and hydrogen peroxide could be remarkably improved using immunoaffinity-layered glucose oxidase and horseradish peroxidase. For the detection of glucose, a Clark-type oxygen electrode, constructed as a small flow-through cell integrated with a cartridge bearing immunoaffinity-layered glucose oxidase was employed. The hydrogen peroxide concentration was analysed spectrophotometrically using a flow-through cell and the layered horseradish peroxidase packed into a cartridge. The immunoaffinity-layered enzymes could be conveniently solubilized at acid pH and fresh enzyme loaded onto the support. Immunoaffinity-layered glucose oxidase was successfully used for the on-line monitoring of the glucose concentration during the cultivation of Streptomyces cerevisiae.


Assuntos
Aspergillus niger/enzimologia , Cromatografia de Afinidade/métodos , Enzimas Imobilizadas , Análise de Injeção de Fluxo/métodos , Proteínas Fúngicas/metabolismo , Glucose Oxidase/metabolismo , Glucose/análise , Peroxidase do Rábano Silvestre/metabolismo , Peróxido de Hidrogênio/análise , Técnicas de Imunoadsorção , Animais , Anticorpos Antifúngicos/imunologia , Calibragem , Eletrodos , Análise de Injeção de Fluxo/instrumentação , Proteínas Fúngicas/imunologia , Glucose Oxidase/imunologia , Peroxidase do Rábano Silvestre/imunologia , Concentração de Íons de Hidrogênio , Soros Imunes , Imunoglobulina G/imunologia , Proteínas de Plantas/imunologia , Proteínas de Plantas/metabolismo , Coelhos , Sensibilidade e Especificidade , Espectrofotometria , Temperatura
18.
J Biotechnol ; 55(3): 171-9, 1997 Jul 04.
Artigo em Inglês | MEDLINE | ID: mdl-9249993

RESUMO

A simple strategy for increasing considerably the quantities of glycoenzymes immobilized on insoluble supports is described. The strategy that we call bioaffinity layering makes use of the multivalent nature of concanavalin A (Con A) and the multiple oligosaccharide chains of most glycoenzymes to build alternating lectin and glycoenzyme layers on a Sepharose matrix with precoupled Con A. Using this procedure, it was possible to increase the amounts of several glycoenzymes immobilized on Sepharose and 19.0 mg glucose oxidase could be associated with one ml Sepharose matrix after seven Con A/glucose oxidase incubation cycles. Bioaffinity layered preparations of glycoenzymes exhibited high activities as indicated by very high effectiveness factor (eta) values and those of glucose oxidase and invertase exhibited a layer-by-layer increase in thermostability. The sensitivity of a flow-through glucose monitoring cartridge integrated into a flow injection analysis (FIA) system was enhanced significantly by increasing the amount of immobilized glucose oxidase via bioaffinity layering. A cartridge bearing six layers of glucose oxidase on Sepharose support was used effectively and repeatedly for analysis of medium glucose concentration during a fed-batch cultivation of the yeast Saccharomyces cerevisiae.


Assuntos
Técnicas Biossensoriais , Enzimas Imobilizadas , Glucose/análise , Concanavalina A/metabolismo , Estabilidade Enzimática , Enzimas Imobilizadas/metabolismo , Glucana 1,4-alfa-Glucosidase/metabolismo , Glucose Oxidase/metabolismo , Glicosídeo Hidrolases/metabolismo , Cinética , Lectinas/metabolismo , Oligossacarídeos/metabolismo , Saccharomyces cerevisiae/química , Saccharomyces cerevisiae/metabolismo , Sefarose , beta-Frutofuranosidase , beta-Galactosidase/metabolismo
19.
Artigo em Inglês | MEDLINE | ID: mdl-9444028

RESUMO

Road traffic accidents result in substantial injury and death in Karachi. We reviewed the patient logs of the two largest government hospitals in Karachi between December 1993 and February 1994 to identify those persons most likely to be injured in a road traffic accident and to identify the vehicle types which were most likely to be involved. 86% of 727 road injury victims were male. Their mean age was 31 years. One hundred of thirty-one (18%) died. Pedestrians and motorcyclists were the most common victims accounting for 46% all injuries and 51% of deaths. Although buses and trucks were less than 4% of the registered vehicles in Karachi they were the striking vehicle among 49% of all injuries and 65% of the deaths. Road traffic accidents disproportionately affect wage earners. Specific interventions to improve the road safety of trucks and buses are needed.


Assuntos
Acidentes de Trânsito/estatística & dados numéricos , Veículos Automotores/classificação , Ferimentos e Lesões/epidemiologia , Acidentes de Trânsito/prevenção & controle , Adulto , Feminino , Hospitalização/estatística & dados numéricos , Humanos , Masculino , Mortalidade , Paquistão/epidemiologia , Risco , Ferimentos e Lesões/prevenção & controle
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