Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 44
Filtrar
1.
BMC Genomics ; 22(1): 749, 2021 Oct 17.
Artículo en Inglés | MEDLINE | ID: mdl-34657595

RESUMEN

BACKGROUND: Bovine milk contains extracellular vesicles (EVs) that play a role in cellular communication, acting in either an autocrine, paracrine, or an exocrine manner. The unique properties of the EVs protect the cargo against degradation. We profiled the ncRNAs (non-coding RNA) present in the EVs from seven dairy products - raw whole milk, heat-treated skim milk, homogenized heat-treated skim milk, pasteurized homogenized skim milk, pasteurized heavy whipping cream, sweet cream buttermilk and cultured buttermilk with four replicates each, obtained at different processing steps from a commercial dairy plant. EVs and their cargo were extracted by using a validated commercial kit that has been shown to be efficient and specific for EVs. Further, to find the annotation of ncRNAs, we probed bovine and other organism repositories(such as miRBase, miRTarBase, Ensemble) to find homolog ncRNA annotation in case the annotations of ncRNA are not available in Bos Taurus database. RESULTS: Specifically, 30 microRNAs (miRNAs), were isolated throughout all the seven milk samples, which later when annotated with their corresponding 1546 putative gene targets have functions associated with immune response and growth and development. This indicates the potential for these ncRNAs to beneficially support mammary health and growth for the cow as well as neonatal gut maturation. The most abundant miRNAs were bta-miR-125a and human homolog miR-718 based on the abundance values of read count obtained from the milk samples.bta-miR-125a is involved in host bacterial and viral immune response, and human homolog miR-718 is involved in the regulation of p53, VEGF, and IGF signaling pathways, respectively. Sixty-two miRNAs were up-regulated and 121 miRNAs were down-regulated throughout all the milk samples when compared to raw whole milk. In addition, our study explored the putative roles of other ncRNAs which included 88 piRNAs (piwi-interacting RNA), 64 antisense RNAs, and 105 lincRNAs (long-intergenic ncRNAs) contained in the bovine exosomes. CONCLUSION: Together, the results indicate that bovine milk contains significant numbers of ncRNAs with putative regulatory targets associated with immune- and developmental-functions important for neonatal bovine health, and that processing significantly affects the ncRNA expression values; but statistical testing of overall abundance(read counts) of all miRNA samples suggests abundance values aren't much affected. This can be attributed to the breakage of exosomal vesicles during the processing stages. It is worth noting, however, that these gene regulatory targets are putative, and further evidence could be generated through experimental validation.


Asunto(s)
Exosomas , Vesículas Extracelulares , MicroARNs , Leche/química , Animales , Bovinos , Femenino , Inmunidad , MicroARNs/genética , ARN no Traducido/genética
2.
Curr Top Med Chem ; 21(4): 269-294, 2021.
Artículo en Inglés | MEDLINE | ID: mdl-32901584

RESUMEN

BACKGROUND: Molecular docking is in regular practice to assess ligand affinity on a target protein crystal structure. In the absence of protein crystal structure, the homology modeling or comparative modeling is the best alternative to elucidate the relationship details between a ligand and protein at the molecular level. The development of accurate homology modeling (HM) and its integration with molecular docking (MD) is essential for successful, rational drug discovery. OBJECTIVE: The G-protein coupled receptors (GPCRs) are attractive therapeutic targets due to their immense role in human pharmacology. The GPCRs are membrane-bound proteins with the complex constitution, and the understanding of their activation and inactivation mechanisms is quite challenging. Over the past decade, there has been a rapid expansion in the number of solved G-protein-coupled receptor (GPCR) crystal structures; however, the majority of the GPCR structures remain unsolved. In this context, HM guided MD has been widely used for structure-based drug design (SBDD) of GPCRs. METHODS: The focus of this review is on the recent (i) developments on HM supported GPCR drug discovery in the absence of GPCR crystal structures and (ii) application of HM in understanding the ligand interactions at the binding site, virtual screening, determining receptor subtype selectivity and receptor behaviour in comparison with GPCR crystal structures. RESULTS: The HM in GPCRs has been extremely challenging due to the scarcity in template structures. In such a scenario, it is difficult to get accurate HM that can facilitate understanding of the ligand-receptor interactions. This problem has been alleviated to some extent by developing refined HM based on incorporating active /inactive ligand information and inducing protein flexibility. In some cases, HM proteins were found to outscore crystal structures. CONCLUSION: The developments in HM have been highly operative to gain insights about the ligand interaction at the binding site and receptor functioning at the molecular level. Thus, HM guided molecular docking may be useful for rational drug discovery for the GPCRs mediated diseases.


Asunto(s)
Receptores Acoplados a Proteínas G/química , Cristalografía por Rayos X , Diseño de Fármacos , Humanos , Ligandos , Simulación del Acoplamiento Molecular , Unión Proteica , Conformación Proteica
3.
Homo ; 68(6): 487-494, 2017 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-29032805

RESUMEN

Obesity is fast becoming an epidemic among the urban children and it has its adverse effect on the status of health even during adulthood. In this paper an attempt is made to assess the percentage of obesity among 6-10 year children and assess the effect of different socio-economic variables and TV watching on childhood obesity. We restricted our study to primary school-going children who attended classes I-IV. The sample consisted of 5216 children from 20 different Bengali medium and English medium schools in Kolkata. Categorical logistic regression of obesity on the socio-economic factors namely type of medium school, religion, parent's education, duration of television watching etc., has been carried out. The categorical logistic regression shows the significant effect of some of the socio-economic or demographic variables including the duration of television watching on obesity. We have seen a positive association between obesity and TV watching and also between obesity and consumption of fast food. This calls for making the parents aware and taking action as early as possible.


Asunto(s)
Índice de Masa Corporal , Conducta Infantil/psicología , Obesidad Infantil/epidemiología , Clase Social , Factores Socioeconómicos , Televisión , Niño , Estudios Transversales , Ejercicio Físico/fisiología , Femenino , Humanos , India/epidemiología , Estilo de Vida , Masculino , Actividad Motora , Obesidad Infantil/economía , Obesidad Infantil/psicología
4.
J Med Chem ; 60(1): 322-337, 2017 01 12.
Artículo en Inglés | MEDLINE | ID: mdl-27996269

RESUMEN

The development of small molecule inhibitors targeting GPVI has promising therapeutic role, as they inhibit arterial thrombosis with limited risk of bleeding. Among the compounds showing in vivo antithrombotic activity, the most active compound 6b (ED50 = 28.36 µmol/kg po in mice) showed improved inhibition for collagen (IC50 = 6.7 µM), CRP-XL (IC50 = 53.5 µM), and convulxin (CVX) (IC50 = 5.7 µM) mediated platelet aggregation as compared to losartan (LOS) (collagen, IC50 = 10.4 µM; CRP-XL, IC50 = 158 µM; CVX, IC50 = 11 µM) than any of its enantiomers S (6c) (collagen, IC50 = 25.3 µM; CRP-XL, IC50 = 181.4 µM; CVX, IC50 = 9 µM) and R (6d) (collagen, IC50 = 126.3 µM; CRP-XL, IC50 > 500 µM; CVX, IC50 = 86.8 µM). Compound 6b also inhibited platelet P-selectin expression and thus may diminish atherosclerosis. The molecular interactions of both enantiomers 6c and 6d at the GPVI receptor have been explained through docking studies.


Asunto(s)
Antitrombinas/farmacología , Indoles/química , Indoles/farmacología , Glicoproteínas de Membrana Plaquetaria/antagonistas & inhibidores , Animales , Antitrombinas/química , Humanos , Ratones , Modelos Moleculares , Agregación Plaquetaria/efectos de los fármacos
5.
Curr Comput Aided Drug Des ; 11(1): 72-83, 2015.
Artículo en Inglés | MEDLINE | ID: mdl-26126610

RESUMEN

Induction of apoptosis by the activation of caspase 3 makes it a promising target for designing anticancer drugs hence an investigation for the essential structural features mandatory for caspase 3 activation has been carried out using a dataset comprising of caspase 3 activator candidate drug Azixa in phase II clinical trial and its analogs using DS2.0. A training set of 40 compounds was selected for the purpose of model generation from 76 molecules with an activity range spanning from 0.002µM to 6.9µM. Among the generated pharmacophore models, the best model Hypo1 constituted by two hydrophobic aliphatic (Hal), two hydrophobic aromatic (Har), and one hydrogen bond acceptor (HBA) features with a correlation coefficient of 0.85, and a cost difference (null cost - total cost) of 46 bits well predicted the test set of 36 compounds (Rpred = 0.8). The key mechanism conferring caspase 3 activation is due to binding of Azixa at ß-tubulin site that is located close to or at same site as colchicine. In the absence of co-crystal structure we have proposed a binding mode of Azixa at the tubulin site by performing docking studies and performed molecular dynamics simulation to ascertain the temporal changes of the protein-ligand complex.


Asunto(s)
Caspasa 3/metabolismo , Activación Enzimática/efectos de los fármacos , Quinazolinas/química , Quinazolinas/farmacología , Tubulina (Proteína)/metabolismo , Antineoplásicos/química , Antineoplásicos/farmacología , Diseño de Fármacos , Humanos , Simulación del Acoplamiento Molecular , Simulación de Dinámica Molecular , Neoplasias/tratamiento farmacológico , Neoplasias/metabolismo
6.
Xenobiotica ; 45(11): 1016-23, 2015.
Artículo en Inglés | MEDLINE | ID: mdl-26084373

RESUMEN

1. S002-333 [(2-(4'-methoxy-benzenesulfonyl)-2,3,4,9-tetrahydro-1H-pyrido (3,4-b) indole-3-carboxylic acid amide)] is a novel and potent antithrombotic active agent. The present work investigates the pharmacokinetics, bioavailability, dose proportionality and permeability of the racemate, S002-333 in male New Zealand White (NZW) rabbits. 2. Rabbits were administered single intravenous (i.v.) (2 mg/kg) and three oral doses of 10, 20 and 40 mg/kg of S002-333, respectively, at different occasions to evaluate dose proportionality. Serial blood samples were collected and analyzed by a liquid chromatography tandem mass spectrometry (LC-MS/MS) method. Since S002-333 is a racemate consisting of S004-1032 (R) and S007-1558 (S), same samples were analyzed using a chiralcel column so as to evaluate the respective enantiomers. 3. The peak plasma concentration, after oral administration, occurred at ∼10 h post-dose. The clearance (CL) and volume of distribution (Vd) after i.v. dose were found to be 3.05 ± 0.09 l/h/kg and 6.73 ± 1.16 l/kg, respectively. The absolute oral bioavailability of S002-333 was 16.32%, whereas it was 6.62 and 5.90% for R- and S-enantiomers, respectively. The absolute bioavailability of 10, 20 and 40 mg/kg doses were found to be 27.91, 14.39 and 16.91%, respectively. The PAMPA (parallel artificial membrane permeability assay) assay shows that S002-333 has a low-passive permeability at gastric and intestinal environment. 4. In conclusion, S002-333 has low-passive permeability, low CL and large Vd. The R-enantiomer has a "slightly" greater bioavailability than the S-enantiomer.


Asunto(s)
Carbolinas/farmacología , Carbolinas/farmacocinética , Sulfonamidas/farmacología , Sulfonamidas/farmacocinética , Administración Oral , Animales , Relación Dosis-Respuesta a Droga , Masculino , Permeabilidad , Conejos
7.
Chem Biol Drug Des ; 86(4): 440-6, 2015 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-25546316

RESUMEN

Antibiotic resistance has been the subject of interest in clinical practice due to high prevalence of antibiotic-resistant pathogenic organisms. In view of the prevalence of lesser resistance in antibiotics belonging to aminoglycoside class of compounds viz. Food and Drug Administration-approved gentamicin for the treatment of Staphylococcus infections, which also has instances of resistance in the clinical isolates of Staphylococcus aureus, a series of novel glycoconjugates of 8-fluoro norfloxacin analogues with high regio-selectivity by employing copper (I)-catalyzed 1, 3-dipolar cycloaddition of 1-O-propargyl monosaccharides has been synthesized and evaluated for the antibacterial activity against gentamicin resistance Staphylococcus aureus. Among these compounds, the compound 10g showed better antibacterial activity (MIC = 3.12 µg/ml) than gentamicin (Escherichia coli (12.5 µg/ml), Staphylococcus aureus (6.25 µg/ml) and Klebsiella pneumonia (6.25 µg/ml), including gentamicin resistant (>50 µg/ml) strain in vitro). The docking studies suggest DNA gyrase of Staphylococcus aureus as a probable target for the antibacterial action of compound 10g.


Asunto(s)
Farmacorresistencia Bacteriana , Gentamicinas , Glicoconjugados , Modelos Moleculares , Norfloxacino , Staphylococcus aureus/crecimiento & desarrollo , Glicoconjugados/síntesis química , Glicoconjugados/química , Glicoconjugados/farmacología , Norfloxacino/análogos & derivados , Norfloxacino/síntesis química , Norfloxacino/química , Norfloxacino/farmacología , Infecciones Estafilocócicas/tratamiento farmacológico
8.
J Chem Inf Model ; 51(8): 1966-85, 2011 Aug 22.
Artículo en Inglés | MEDLINE | ID: mdl-21761917

RESUMEN

The current study deciphers the combined ligand- and structure-based computational insights to profile structural determinants for the selectivity of representative diverse classes of FXa-selective and thrombin-selective as well as dual FXa-thrombin high affinity inhibitors. The thrombin-exclusive insertion 60-loop (D-pocket) was observed to be one of the most notable recognition sites for the known thrombin-selective inhibitors. Based on the topological comparison of four common active-site pockets (S1-S4) of FXa and thrombin, the greater structural disparity was observed in the S4-pocket, which was more symmetrical (U-shaped) in FXa as compared to thrombin mainly due to the presence of L99 and I174 residues in latter in place of Y99 and F174 respectively in former protease. The S2 pocket forming partial roof at the entry of 12 Å deep S1-pocket, with two extended ß-sheets running antiparallel to each other by undergoing U-turn (∼180̊), has two conserved glycine residues forming H-bonds with the bound ligand for governing ligand binding affinity. The docking, scoring, and binding pose comparison of the representative high-affinity and selective inhibitors into the active sites of FXa and thrombin revealed critical residues (S214, Y99, W60D) mediating selectivity through direct- and long-range electrostatic interactions. Interestingly, most of the thrombin-selective inhibitors attained S-shaped conformation in thrombin, while FXa-selective inhibitors attained L-shaped conformations in FXa. The role of residue at 99th position of FXa and thrombin toward governing protease selectivity was further substantiated using molecular dynamics simulations on the wild-type and mutated Y99L FXa bound to thrombin-selective inhibitor 2. Furthermore, predictive CoMFA (FXa q² = 0.814; thrombin q² = 0.667) and CoMSIA (FXa q² = 0.807; thrombin q² = 0.624) models were developed and validated (FXa r²(test) = 0.823; thrombin r(2)(test) = 0.816) to feature molecular determinants of ligand binding affinity using the docking-based conformational alignments (DBCA) of 141 (88(train)+53(test)) and 39 (27(train)+11(test)) nonamidine class of potent FXa (0.004 ≤ K(i) (nM) ≤ 4700) and thrombin (0.001 ≤ K(i) (nM) ≤ 940) inhibitors, respectively. Interestingly, the ligand-based insights well corroborated with the structure-based insights in terms of the role of steric, electrostatic, and hydrophobic parameters for governing the selectivity for the two proteases. The new computational insights presented in this study are expected to be valuable for understanding and designing potent and selective antithrombotic agents.


Asunto(s)
Anticoagulantes/química , Factor Xa , Fibrinolíticos/química , Simulación de Dinámica Molecular , Inhibidores de Serina Proteinasa/química , Trombina , Secuencia de Aminoácidos , Anticoagulantes/metabolismo , Anticoagulantes/farmacología , Sitios de Unión , Cristalografía por Rayos X , Bases de Datos de Proteínas , Factor Xa/química , Factor Xa/metabolismo , Inhibidores del Factor Xa , Fibrinolíticos/metabolismo , Fibrinolíticos/farmacología , Humanos , Enlace de Hidrógeno , Interacciones Hidrofóbicas e Hidrofílicas , Ligandos , Datos de Secuencia Molecular , Unión Proteica , Estructura Secundaria de Proteína , Estructura Terciaria de Proteína , Sensibilidad y Especificidad , Inhibidores de Serina Proteinasa/metabolismo , Inhibidores de Serina Proteinasa/farmacología , Electricidad Estática , Relación Estructura-Actividad , Trombina/antagonistas & inhibidores , Trombina/química , Trombina/metabolismo , Trombosis/tratamiento farmacológico , Trombosis/metabolismo , Trombosis/fisiopatología
9.
Chem Biol Drug Des ; 78(3): 483-93, 2011 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-21672165

RESUMEN

The integrated ligand- and structure-based drug design techniques have been applied on a homogeneous dataset of thiolactone-class of potent anti-malarials, to explore the essential structural features for the inhibition of Plasmodium falciparum. Developed CoMFA (q(2) = 0.716) and CoMSIA (q(2) = 0.632) models well explained structure-activity variation in both the training (CoMFA R(2) = 0.948 & CoMSIA R(2) = 0.849) and test set (CoMFA R(2) (pred) = 0.789 & CoMSIA R(2) (pred) = 0.733) compounds. The docking and scoring of the most active compound 10 into the active site of high-resolution (2.35 Å) structure of FabB-TLM binary complex (PDB-ID: 1FJ4) indicated that thiolactone core of this compound forms bifurcated H-bonding with two catalytic residues His298 and His333, and its saturated decyl side group is stabilized by hydrophobic interactions with the residues of a small hydrophobic groove, illustrating that the active site architecture, including two catalytic histidines and a small hydrophobic groove, is vital for protein-ligand interaction. In particular, the length and flexibility of the side group attached to the position 5 of thiolactone have been observed to play a significant role in the interaction with FabB enzyme. These results present scope for rational design of thiolactone-class of compounds that could furnish improved anti-malarial activity.


Asunto(s)
Antimaláricos/química , Antimaláricos/farmacología , Diseño de Fármacos , Plasmodium falciparum/efectos de los fármacos , Humanos , Malaria Falciparum/tratamiento farmacológico , Modelos Moleculares , Relación Estructura-Actividad Cuantitativa , Tiofenos/química , Tiofenos/farmacología
10.
J Pharmacol Toxicol Methods ; 60(2): 159-66, 2009.
Artículo en Inglés | MEDLINE | ID: mdl-19616109

RESUMEN

INTRODUCTION: Conscious telemeterised rats are used for early assessment of cardiovascular drug safety. This paper details the surgery required to allow key cardiovascular parameters to be determined and describes how QA interval (QAI), a surrogate measure of cardiac contractility, is related to a more direct measure of cardiac contractility, dP/dt(max) (LVdP/dt(max)). Experimental studies examining the effect of both positive and negative inotropes are described. METHODS: Eight rats were surgically implanted with telemetry probes for measuring blood pressure, heart rate, activity, body temperature and ECG parameters. Initial studies focussed on evaluating surgical procedures aimed at improving the ECG signal to allow QAI quantification. Once achieved, experimental studies were undertaken with verapamil, salmeterol, milrinone or vehicle. Following treatment, data was collected for approximately 20 h from pair-housed animals to establish effects on QAI or LVdP/dt(max), which was measured directly from the left ventricle in a separate group of rats. RESULTS: The modified ECG lead placement produced both a qualitative and quantitative improvement in ECGs. Increases in cardiac contractility (measured directly) were paralleled by a decrease in QAI (measured indirectly). Salmeterol and milrinone increased (all p<0.05) LVdP/dt(max) (1942+/-452 and 2333+/-506 mmHg/s, respectively) and decreased QAI (3.5+/-0.54 and 2.9+/-0.43 ms, respectively). In contrast, the negative inotrope verapamil decreased LVdP/dtmax (-2119+/-300 mmHg/s) and increased QAI (4.9+/-0.46 ms). A statistically significant (p<0.001) linear relationship was identified between log(10)(QAI) and log(10)(LVdP/dt(max)). DISCUSSION: Improvements in ECG signal quality, resulting from refinements in surgical techniques allowed for the reliable quantification of ECG parameters. The linear relationship demonstrated between log(10)(QAI) and log(10)(LVdP/dt(max)) indicates that QAI may be a useful index of cardiac contractility in routine rat cardiovascular safety studies. These limited studies support the use of QAI as an indirect measure of cardiac contractility in the rat.


Asunto(s)
Frecuencia Cardíaca/efectos de los fármacos , Contracción Miocárdica/efectos de los fármacos , Telemetría/métodos , Animales , Presión Sanguínea/efectos de los fármacos , Temperatura Corporal/efectos de los fármacos , Fármacos Cardiovasculares/farmacología , Estado de Conciencia , Evaluación Preclínica de Medicamentos/instrumentación , Evaluación Preclínica de Medicamentos/métodos , Electrocardiografía/efectos de los fármacos , Guías como Asunto , Masculino , Modelos Animales , Modelos Cardiovasculares , Ratas , Ratas Sprague-Dawley , Telemetría/instrumentación , Factores de Tiempo , Función Ventricular Izquierda/efectos de los fármacos
11.
Comput Cardiol ; 36: 105-108, 2009.
Artículo en Inglés | MEDLINE | ID: mdl-26997739

RESUMEN

Electrocardiographic (ECG) ST segment shifts are often used as markers for detecting myocardial ischemia. Literature suggests that the progression of ischemia, occurs from the endocardium and spreads towards the epicardium, eventually becoming transmural. Our study with animal models has found the progression of ischemia, characterized by ST elevations to be more complex and heterogeneous in its distribution. We used in situ canine preparations, wherein the animals were subjected to demand ischemia by reducing coronary flow and raising the heart rate through atrial pacing. At reduced flow, increasing the heart rate caused pockets of ST elevations to appear variously distributed in the sub-epicardial, midmyocardial and endocardial regions. Further reduction in coronary flow with simultaneous raising of the heart rate, increased the extent and magnitude of ST elevated regions, that in certain cases became transmural.

12.
Med Biol Eng Comput ; 43(6): 776-82, 2005 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-16594306

RESUMEN

The results of a geometric model of cardiac tissue, used to compute the bidomain conductivity tensors during three phases of ischaemia, are described. Ischaemic conditions were simulated by model parameters being changed to match the morphological and electrical changes of three phases of ischaemia reported in literature. The simulated changes included collapse of the interstitial space, cell swelling and the closure of gap junctions. The model contained 64 myocytes described by 2 million tetrahedral elements, to which an external electric field was applied, and then the finite element method was used to compute the associated current density. In the first case, a reduction in the amount of interstitial space led to a reduction in extracellular longitudinal conductivity by about 20%, which is in the range of reported literature values. Moderate cell swelling in the order of 10-20% did not affect extracellular conductivity considerably. To match the reported drop in total tissue conductance reported in experimental studies during the third phase of ischaemia, a ten fold increase in the gap junction resistance was simulated. This ten-fold increase correlates well with the reported changes in gap junction densities in the literature.


Asunto(s)
Sistema de Conducción Cardíaco/fisiopatología , Modelos Cardiovasculares , Isquemia Miocárdica/fisiopatología , Conductividad Eléctrica , Uniones Comunicantes/fisiología , Humanos , Miocitos Cardíacos/fisiología
13.
J Virol ; 75(17): 8329-39, 2001 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-11483778

RESUMEN

During infection of host cells, a number of enveloped animal viruses are known to produce soluble forms of viral membrane glycoproteins lacking the transmembrane domain. The roles of such soluble glycoproteins in viral life cycles are incompletely understood, but in several cases they are believed to modulate host immune response and viral pathogenesis. Semliki Forest virus (SFV) is an enveloped alphavirus that infects cells through low-pH-dependent fusion and buds from the plasma membrane. Fusion is mediated by the E1 subunit of the SFV spike protein. Previous studies described the in vivo generation of E1s, a truncated soluble form of E1, under conditions in which budding is inhibited in mammalian host cells. We have here examined the properties of E1s generation and the biological activity of E1s. E1s cleavage required spike protein transport out of the endoplasmic reticulum and was independent of virus infection. Cell surface E1 efficiently acted as a precursor for E1s. E1s generation was strongly pH dependent in BHK cells, with optimal cleavage at a pH of < or =7.0, conditions that inhibited the budding of SFV but not the budding of the rhabdovirus vesicular stomatitis virus. The pH dependence of E1s production and SFV budding was unaffected by the stability of the spike protein dimer but was a function of the host cell. Similar to the intact virus and in vitro-generated E1 ectodomain, treatment of E1s at low pH in the presence of target membranes triggered specific acid-dependent conformational changes. Thus, under a variety of conditions, SFV-infected cells can produce a soluble form of E1 that is biologically active.


Asunto(s)
Fusión de Membrana , Glicoproteínas de Membrana/metabolismo , Virus de los Bosques Semliki/fisiología , Proteínas del Envoltorio Viral/metabolismo , Proteínas Virales de Fusión , Animales , Línea Celular , Dimerización , Concentración de Iones de Hidrógeno , Glicoproteínas de Membrana/química , Virus de los Bosques Semliki/patogenicidad , Solubilidad , Spodoptera , Transfección , Proteínas del Envoltorio Viral/química , Proteínas Virales de Fusión/química , Proteínas Virales de Fusión/metabolismo
14.
Int J Geriatr Psychiatry ; 16(5): 477-83, 2001 May.
Artículo en Inglés | MEDLINE | ID: mdl-11376463

RESUMEN

OBJECTIVE: The aim of this study was to compare demographic, illness and personality characteristics, and formal rates of mental disorder between younger (< 65 years) and older (>or= 65 years) patients attending a chronic pain clinic. METHOD: Patients with non-malignant pain of > 6 months' duration attending a specialist outpatient clinic were given a structured medical and psychiatric interview, and completed self-report questionnaires assessing disability, personality style and attitudes to illness. RESULTS: Fifty patients (26 of whom were older) participated in the study. None of the older patients had experienced the onset of chronic pain before the age of 50 years. Although current and lifetime major depression were common in both groups, there was no specific association between age and depression. The younger group was more likely to have been injured prior to the onset of pain and to be seeking financial compensation, reported more physical and social disability, and was more likely to be preoccupied with somatic discomfort. The younger group was also more likely to be rated as displaying impulsive personality traits and the older group anxious traits, although there was no difference in neuroticism scores. CONCLUSION: Despite a greater level of multiple medical morbidity and longer duration of pain, older patients with chronic pain were not more likely to suffer from concurrent depression, were less disabled and less somatically preoccupied than younger patients. There were sufficient differences in illness and psychological characteristics to suggest that the older patients represented an aetiologically distinct sub-group, rather than patients with chronic pain of early onset who have simply grown old. Finally, the utility of DSM-IV defined somatoform disorders, in particular pain disorder, is discussed. A model which integrates medical and psychological mechanisms is needed for clinical use.


Asunto(s)
Depresión/epidemiología , Clínicas de Dolor/estadística & datos numéricos , Dolor/psicología , Trastornos Somatomorfos/epidemiología , Adulto , Factores de Edad , Anciano , Enfermedad Crónica , Depresión/complicaciones , Humanos , Masculino , Persona de Mediana Edad , Nueva Gales del Sur/epidemiología , Dimensión del Dolor , Factores Socioeconómicos , Trastornos Somatomorfos/complicaciones
15.
Virology ; 279(1): 146-60, 2001 Jan 05.
Artículo en Inglés | MEDLINE | ID: mdl-11145898

RESUMEN

Semliki Forest Virus (SFV) is an enveloped alphavirus that infects cells by a low-pH-dependent membrane fusion reaction. SFV fusion is catalyzed by the spike protein E1 subunit, which contains a putative fusion peptide between residues 79 and 97. Prior mutagenesis studies demonstrated that an E1 G91D mutation blocks both virus-membrane fusion and the formation of a highly stable E1 trimer believed to be a critical fusion intermediate. We have here demonstrated that the G91D mutant was also inactive in hemifusion, suggesting that the E1 homotrimer is important in the initial stages of lipid mixing. Revertant analysis of a G91 deletion mutant indicated that G91 was crucial for the viability of SFV. In contrast, a G83D mutation produced infectious virus with both efficient fusion and homotrimer formation. Thus, the G83 position, although highly conserved among alphaviruses, was functional if replaced with a charged amino acid.


Asunto(s)
Glicina/química , Fusión de Membrana , Mutación , Virus de los Bosques Semliki/fisiología , Proteínas Virales de Fusión/química , Secuencia de Aminoácidos , Animales , Línea Celular , Cricetinae , Liposomas/metabolismo , Datos de Secuencia Molecular , Péptidos/química , Péptidos/genética , Péptidos/metabolismo , Fenotipo , Virus de los Bosques Semliki/química , Virus de los Bosques Semliki/genética , Transcripción Genética , Proteínas Virales de Fusión/genética , Proteínas Virales de Fusión/metabolismo , Ensamble de Virus
16.
J Electrocardiol ; 34 Suppl: 43-51, 2001.
Artículo en Inglés | MEDLINE | ID: mdl-11781935

RESUMEN

Despite many years of study, certain aspects of myocardial ischemia remain incompletely understood. One observation that motivated this study is that acute, complete occlusion produces elevations but never depression of the ST-segment potentials in electrocardiographic leads over the ischemic zone. Limited flow, on the other hand, leads to ST-segment depression, both in in situ experiments and during clinical stress tests. The prevailing biophysical theory of ischemia suggests that complete occlusion should produce at least transient ST-segment depression, a finding we have neither observed in our own studies nor uncovered in the literature. Our goal with these experiments was to understand the difference between complete occlusion and reduced coronary flow, specifically the behavior at the transition between the two. We have performed experiments by using isolated dog hearts with a cannulated left anterior descending artery suspended in a human shaped electrolytic tank. To create a range of ischemic conditions, we changed coronary flow rates both suddenly and in controlled sequences and varied the heart rate of the isolated heart. The main finding was that in the isolated heart preparation, epicardial ST-segment depression over the ischemic zone arose only under conditions of combined restricted flow and elevated heart rate. Reduced coronary flow alone never produced ST-segment depression. These findings suggest that heart rate and probably metabolic work create the conditions necessary for subendocardial ischemia that reduced flow alone cannot provoke. They furthermore suggest that the degree of ST-segment depression for a given restriction in coronary flow may depend on heart rate, which supports the notion of rate correction for clinical stress electrocardiogram testing.


Asunto(s)
Circulación Coronaria/fisiología , Electrocardiografía , Frecuencia Cardíaca/fisiología , Isquemia Miocárdica/fisiopatología , Animales , Mapeo del Potencial de Superficie Corporal , Enfermedad Coronaria/diagnóstico , Enfermedad Coronaria/fisiopatología , Perros , Humanos
17.
J ECT ; 15(4): 275-9, 1999 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-10614035

RESUMEN

Electroconvulsive therapy (ECT) was used to treat severe depressive illness in two patients, one of whom had undergone recent neurosurgery for subdural hemorrhage (SDH) and another with a concurrent SDH in the absence of raised intracranial pressure. Although the second patient died 1 month after the completion of ECT, in neither case did ECT extend the SDH or lead to other intracranial complications. It would seem that ECT can be performed safely in the presence of SDH without mass effect or after surgical drainage of SDH, although clinicians should proceed cautiously in close collaboration with neurosurgical colleagues, review neuroimaging scans at regular intervals during and after the course of ECT, and use the dose-titration method of treatment with unilateral electrode placement away from the site of the lesion or surgery to minimize adverse effects.


Asunto(s)
Hemorragia Cerebral/complicaciones , Trastorno Depresivo/terapia , Terapia Electroconvulsiva , Hematoma Subdural/complicaciones , Anciano , Anciano de 80 o más Años , Trastorno Depresivo/complicaciones , Terapia Electroconvulsiva/efectos adversos , Terapia Electroconvulsiva/métodos , Electrodos , Humanos , Masculino , Resultado del Tratamiento
18.
Aust N Z J Psychiatry ; 32(6): 809-14, 1998 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-10084345

RESUMEN

OBJECTIVE: The aim of this paper is to briefly review the literature on early intervention in schizophrenia in the elderly, and to present six cases of schizophrenia in the elderly which highlight the need for assertive management of the type encouraged widely for early onset illness in younger patients. METHOD: Six case histories are presented. RESULTS: All six patients were diagnosed with DSM-IV schizophrenia, all were single and all were socially isolated. They required involuntary admission, treatment with depot antipsychotics, extensive psychosocial intervention and community treatment orders. The use of these treatment strategies led to a positive outcome in each case. CONCLUSION: The authors argue that assertive treatment of elderly patients with schizophrenia should be pursued with the enthusiasm often reserved for younger, early onset patients, and that therapeutic optimism is required and warranted.


Asunto(s)
Esquizofrenia/terapia , Factores de Edad , Edad de Inicio , Anciano , Antipsicóticos/uso terapéutico , Terapia Combinada , Internamiento Obligatorio del Enfermo Mental/legislación & jurisprudencia , Preparaciones de Acción Retardada , Femenino , Evaluación Geriátrica , Humanos , Masculino , Nueva Gales del Sur , Psicoterapia , Esquizofrenia/diagnóstico , Esquizofrenia/tratamiento farmacológico , Psicología del Esquizofrénico , Resultado del Tratamiento
20.
Indian J Psychiatry ; 38(2): 86-92, 1996 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-21584151

RESUMEN

The present work was carried out to study the awareness of non-psychiatric clinicians working in a teaching general hospital about the frequency of psychiatric morbidity in their clinical practice, their utilization of psychiatric consultation services, and opinion about utility of liaison psychiatry in general hospitals. A substantial proportion of doctors underestimated the psychiatric morbidity especially about unexplained physical symptoms and specific depressive symptoms in their patients. Psychiatric consultation services were not sufficiently utilised by a large number of clinicians. Most ofthemfelt the need to improve upon undergraduate medical education in psychiatry in India as well as a desire to have consultation - liaison psychiatric units in India.

SELECCIÓN DE REFERENCIAS
DETALLE DE LA BÚSQUEDA