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1.
Cureus ; 16(4): e58715, 2024 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-38779234

RESUMEN

INTRODUCTION: Sternal dehiscence and other post-sternotomy complications, viz. superficial and deep sternal wound infection, mediastinitis, and sternal instability increase the risk of mortality. Sternotomy closure with steel sutures results in a low complication rate. Therefore, this study compared the clinical equivalence of Trusteel® (Healthium Medtech Limited, Bengaluru, India) and Ethisteel® (Ethicon, Johnson & Johnson, Cincinnati, USA) surgical steel sutures for sternal closure following median sternotomy. METHODS: The primary endpoint of this prospective, single-blind, multicentric, two-arm, randomized (1:1) study (April 2021-April 2023) was a comparison of the proportion of subjects having sternal dehiscence within 26 weeks of the median sternotomy closure between Trusteel® (n=33) and Ethisteel® (n=34) groups. Secondary endpoints comprised an assessment of intraoperative suture handling, the incidence of mortality and other complications of sternal closure, operative time, intensive care unit (ICU)/hospital stay, return to normal day-to-day activities and work, subject satisfaction and general well-being, and adverse events in both groups. A statistically significant result between the groups was considered at p<0.05. RESULTS: No incidence of sternal dehiscence or other post-operative complications were recorded. A significant difference (p<0.05) in the stretch capacity of Trusteel® and Ethisteel® sutures was noted; otherwise, ease of passage, knot holding, knot security, knot tie-down smoothness, and memory of both sutures had comparable ratings. Operative time, ICU/hospital stay, and return to normal day-to-day activities and work were comparable between the groups. Improvement in post-operative functional abilities, quality of life, and health status was evident in both groups and was comparable. CONCLUSION: Trusteel® surgical steel suture is clinically equivalent to Ethisteel® surgical steel suture and is safe and effective for sternal closure following median sternotomy.

2.
Phys Med ; 82: 211-218, 2021 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-33652204

RESUMEN

We propose a novel cost-effective compensator that can be used to facilitate access to IMRT in low-and-middle income countries. The compensator has the advantages of simplicity, less downtime, increased reliability and less impact on treatment quality from patient motion during treatment. Moreover, the system can be used with either a cobalt-60 unit or linear accelerator. In this Monte Carlo study, the dosimetric properties of the new compensator design have been evaluated. Results were obtained for different field sizes of cobalt teletherapy machine, and the dose was scored at 0.5 cm depth in a water phantom. The effects of compensator thickness, filling material type and shape, and field size were identified. Furthermore, the percentage depth dose and beam profiles for various field sizes and at different depths were obtained. Beam profiles show no significant signature of the beads relative to a solid compensator; in addition, they exhibit a better flatness while preserving symmetry for all field sizes. A reusable bead-based compensator appears to be feasible, and provides dose distribution similar to a solid compensator with low cost and no hazards. Our results avail the ongoing efforts to expand the reach to IMRT in low- and middle-income countries.


Asunto(s)
Radioterapia de Intensidad Modulada , Países en Desarrollo , Humanos , Método de Montecarlo , Radiometría , Dosificación Radioterapéutica , Reproducibilidad de los Resultados
3.
Indian J Microbiol ; 59(4): 525-529, 2019 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-31762517

RESUMEN

Microsporidia are intracellular fungal parasites and they are the most common pathogens for sericulture. Microsporidian sp. can cause pebrine, a dreadful disease and lead to destructive disorder in Muga silkworm, Antheraea assamensis Helfer by vertical and horizontal transmission. This disease is the key factor obstructing the developmental progress of Muga culture in India. Nevertheless, molecular identification and characterization of pathogen associated with pebrine disease in A. assamensis is not yet established. Insect bioassay studies revealed that microsporidian infection in Muga silkworm, A. assamensis Helfer significantly reduced (P < 0.005) cocoon weight, pupal weight, shell weight and silk ratios. A new set of PCR primers suitable for amplification of small subunit ribosomal RNA (SSU-rRNA) of microsporidia infecting A. assamensis have been designed. The amplicon was cloned, sequenced and analysed. Microsporidia pathogen of wild silk moth A. assamensis has been identified at genus level as Nosema sp. AA1. Phylogeny of Nosema sp. AA1 was constructed on the basis of SSU-rRNA sequence and it has a close evolutionary relationship with microsporidian pathogens of other wild silkmoths. The arrangement and organization of the rRNA genes inferred that Nosema sp. AA1 belongs to true Nosema group and not to members of the Nosema/Vairimorpha group.

4.
Med Phys ; 45(7): 3275-3286, 2018 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-29777595

RESUMEN

PURPOSE: We propose a novel compensator-based IMRT system designed to provide a simple, reliable, and cost-effective adjunct technology, with the goal of expanding global access to advanced radiotherapy techniques. The system would employ easily reusable tungsten bead compensators that operate independent of a gantry (e.g., mounted in a ring around the patient). Thereby the system can be retrofitted to existing linac and cobalt teletherapy units. This study explores the quality of treatment plans from the proposed system and the dependence on associated design parameters. METHODS: We considered 60 Co-based plans as the most challenging scenario for dosimetry and benchmarked them against clinical MLC-based plans delivered on a linac. Treatment planning was performed in the Pinnacle treatment planning system with commissioning based on Monte Carlo simulations of compensated beams. 60 Co-compensator IMRT plans were generated for five patients with head-and-neck cancer and five with gynecological cancer and compared to respective IMRT plans using a 6 MV linac beam with an MLC. The dependence of dosimetric endpoints on compensator resolution, thickness, position, and number of beams was assessed. Dosimetric accuracy was validated by Monte Carlo simulations of dose distribution in a water phantom from beams with the IMRT plan compensators. RESULTS: The 60 Co-compensator plans had on average equivalent PTV coverage and somewhat inferior OAR sparing compared to the 6 MV-MLC plans, but the differences in dosimetric endpoints were clinically acceptable. Calculated treatment times for head-and-neck plans were 7.6 ± 2.0 min vs 3.9 ± 0.8 min (6 MV-MLC vs 60 Co-compensator) and for gynecological plans were 8.7 ± 3.1 min vs 4.3 ± 0.4 min. Plan quality was insensitive to most design parameters over much of the ranges studied, with no degradation found when the compensator resolution was finer than 6 mm, maximum thickness at least 2 tenth-value-layers, and more than five beams were used. Source-to-compensator distances of 53 and 63 cm resulted in very similar plan quality. Monte Carlo simulations suggest no increase in surface dose for the geometries considered here. Simulated dosimetric validation tests had median gamma pass rates of 97.6% for criteria of 3% (global)/3 mm with a 10% threshold. CONCLUSIONS: The novel ring-compensator IMRT system can produce plans of comparable quality to standard 6 MV-MLC systems. Even when 60 Co beams are used the plan quality is acceptable and treatment times are substantially reduced. 60 Co-compensator IMRT plans are adequately modeled in an existing commercial treatment planning system. These results motivate further development of this low-cost adaptable technology with translation through clinical trials and deployment to expand the reach of IMRT in low- and middle-income countries.


Asunto(s)
Países en Desarrollo , Planificación de la Radioterapia Asistida por Computador/métodos , Radioterapia de Intensidad Modulada/métodos , Análisis Costo-Beneficio , Diseño de Equipo , Método de Montecarlo , Radiometría , Dosificación Radioterapéutica , Radioterapia de Intensidad Modulada/economía , Radioterapia de Intensidad Modulada/instrumentación
5.
Appl Opt ; 56(24): 6949-6955, 2017 Aug 20.
Artículo en Inglés | MEDLINE | ID: mdl-29048040

RESUMEN

We propose and demonstrate a compressive sensing (CS) framework for correlation holography. This is accomplished by adopting the principle of compressive sensing and thresholding in the two-point intensity correlation. The measurement matrix and the sensing matrix that are required for applying the CS framework here are systematically extracted from the random illuminations of the laser speckle data. Reconstruction results using CS, CS with thresholding, and intensity correlation are compared. Our study reveals that liminal CS requires far fewer samples for the reconstruction of the hologram and has wide application in image reconstruction.

6.
J Opt Soc Am A Opt Image Sci Vis ; 33(12): 2516-2525, 2016 Dec 01.
Artículo en Inglés | MEDLINE | ID: mdl-27906279

RESUMEN

The need for image fusion in current image processing systems is increasing mainly due to the increased number and variety of image acquisition techniques. Image fusion is the process of combining substantial information from several sensors using mathematical techniques in order to create a single composite image that will be more comprehensive and thus more useful for a human operator or other computer vision tasks. This paper presents a new approach to multifocus image fusion based on sparse signal representation. Block-based compressive sensing integrated with a projection-driven compressive sensing (CS) recovery that encourages sparsity in the wavelet domain is used as a method to get the focused image from a set of out-of-focus images. Compression is achieved during the image acquisition process using a block compressive sensing method. An adaptive thresholding technique within the smoothed projected Landweber recovery process reconstructs high-resolution focused images from low-dimensional CS measurements of out-of-focus images. Discrete wavelet transform and dual-tree complex wavelet transform are used as the sparsifying basis for the proposed fusion. The main finding lies in the fact that sparsification enables a better selection of the fusion coefficients and hence better fusion. A Laplacian mixture model fit is done in the wavelet domain and estimation of the probability density function (pdf) parameters by expectation maximization leads us to the proper selection of the coefficients of the fused image. Using the proposed method compared with the fusion scheme without employing the projected Landweber (PL) scheme and the other existing CS-based fusion approaches, it is observed that with fewer samples itself, the proposed method outperforms other approaches.

7.
J Opt Soc Am A Opt Image Sci Vis ; 33(3): 326-32, 2016 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-26974901

RESUMEN

In this paper, we propose a particle-filter-based technique for the analysis of a reconstructed interference field. The particle filter and its variants are well proven as tracking filters in non-Gaussian and nonlinear situations. We propose to apply the particle filter for direct estimation of phase and its derivatives from digital holographic interferometric fringes via a signal-tracking approach on a Taylor series expanded state model and a polar-to-Cartesian-conversion-based measurement model. Computation of sample weights through non-Gaussian likelihood forms the major contribution of the proposed particle-filter-based approach compared to the existing unscented-Kalman-filter-based approach. It is observed that the proposed approach is highly robust to noise and outperforms the state-of-the-art especially at very low signal-to-noise ratios (i.e., especially in the range of -5 to 20 dB). The proposed approach, to the best of our knowledge, is the only method available for phase estimation from severely noisy fringe patterns even when the underlying phase pattern is rapidly varying and has a larger dynamic range. Simulation results and experimental data demonstrate the fact that the proposed approach is a better choice for direct phase estimation.

8.
Appl Opt ; 53(19): 4150-7, 2014 Jul 01.
Artículo en Inglés | MEDLINE | ID: mdl-25089973

RESUMEN

In this research work, we introduce a novel approach for phase estimation from noisy reconstructed interference fields in digital holographic interferometry using an unscented Kalman filter. Unlike conventionally used unwrapping algorithms and piecewise polynomial approximation approaches, this paper proposes, for the first time to the best of our knowledge, a signal tracking approach for phase estimation. The state space model derived in this approach is inspired from the Taylor series expansion of the phase function as the process model, and polar to Cartesian conversion as the measurement model. We have characterized our approach by simulations and validated the performance on experimental data (holograms) recorded under various practical conditions. Our study reveals that the proposed approach, when compared with various phase estimation methods available in the literature, outperforms at lower SNR values (i.e., especially in the range 0-20 dB). It is demonstrated with experimental data as well that the proposed approach is a better choice for estimating rapidly varying phase with high dynamic range and noise.

9.
J Cell Biochem ; 110(5): 1082-93, 2010 Aug 01.
Artículo en Inglés | MEDLINE | ID: mdl-20564204

RESUMEN

Plumbagin inhibited activation, proliferation, cytokine production, and graft-versus-host disease in lymphocytes and inhibited growth of tumor cells by suppressing nuclear factor-kappaB (NF-kappaB). Plumbagin was also shown to induce reactive oxygen species (ROS) generation in tumor cells via an unknown mechanism. Present report describes a novel role of cellular redox in modulation of immune responses in normal lymphocytes by plumbagin. Plumbagin depleted glutathione (GSH) levels that led to increase in ROS generation. The decrease in GSH levels was due to direct reaction of plumbagin with GSH as evinced by mass spectrometric and HPLC analysis. Further, addition of plumbagin to cells resulted in decrease in free thiol groups on proteins and increase in glutathionylation of proteins. The suppression of mitogen-induced T-cell proliferation and cytokine (IL-2/IL-4/IL-6/IFN-gamma) production by plumbagin was abrogated by thiol antioxidants but not by non-thiol antioxidants confirming that thiols but not ROS play an important role in biological activity of plumbagin. Plumbagin also abrogated mitogen-induced phosphorylation of ERK, IKK, and degradation of IkappaB-alpha. However, it did not affect phosphorylation of P38, JNK, and AKT. Our results for the first time show that antiproliferative effects of plumbagin are mediated by modulation of cellular redox. These results provide a rationale for application of thiol-depleting agents as anti-inflammatory drugs.


Asunto(s)
Proliferación Celular/efectos de los fármacos , Citocinas/metabolismo , Naftoquinonas/farmacología , Compuestos de Sulfhidrilo/metabolismo , Linfocitos T/efectos de los fármacos , Adyuvantes Inmunológicos/farmacología , Animales , Western Blotting , Catalasa/metabolismo , Células Cultivadas , Concanavalina A/farmacología , Glutatión/metabolismo , Mediadores de Inflamación/metabolismo , Interferón gamma/metabolismo , Interleucina-2/metabolismo , Interleucina-4/metabolismo , Interleucina-6/metabolismo , Espacio Intracelular/efectos de los fármacos , Espacio Intracelular/metabolismo , Activación de Linfocitos , Masculino , Ratones , Mitógenos/farmacología , Oxidación-Reducción/efectos de los fármacos , Especies Reactivas de Oxígeno/metabolismo , Superóxido Dismutasa/metabolismo , Linfocitos T/citología , Linfocitos T/metabolismo
10.
J Opt Soc Am A Opt Image Sci Vis ; 27(5): 1091-9, 2010 May 01.
Artículo en Inglés | MEDLINE | ID: mdl-20448776

RESUMEN

We address the problem of inpainting noisy photographs. We present a recursive image recovery scheme based on the unscented Kalman filter (UKF) to simultaneously inpaint identified damaged portions in an image and suppress film-grain noise. Inpainting of the missing observations is guided by a mask-dependent reconstruction of the image edges. Prediction within the UKF is based on a discontinuity-adaptive Markov random field prior that attempts to preserve edges while achieving noise reduction in uniform regions. We demonstrate the capability of the proposed method with many examples.

11.
IEEE Trans Image Process ; 17(10): 1969-74, 2008 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-18784043

RESUMEN

This correspondence proposes a recursive algorithm for noise reduction in synthetic aperture radar imagery. Excellent despeckling in conjunction with feature preservation is achieved by incorporating a discontinuity-adaptive Markov random field prior within the unscented Kalman filter framework through importance sampling. The performance of this method is demonstrated on both synthetic and real examples.


Asunto(s)
Algoritmos , Aumento de la Imagen/métodos , Interpretación de Imagen Asistida por Computador/métodos , Imagenología Tridimensional/métodos , Radar , Reproducibilidad de los Resultados , Sensibilidad y Especificidad
12.
J Environ Pathol Toxicol Oncol ; 20(3): 189-97, 2001.
Artículo en Inglés | MEDLINE | ID: mdl-11797828

RESUMEN

It is now widely accepted that cancer development is a multistage process, starting from the original cell population and ending with a malignant tumor. However, the mechanisms involved in the progressive growth of cells from normalcy to preneoplasia, and from preneoplasia to malignancy are not clear. Because tyrosine phosphorylation and dephosphorylation reactions are known to play critical roles during normal and abnormal cellular growth, we have studied the tyrosine phosphorylation, tyrosine phosphorylated proteins, and protein phosphatases during the sequential development of liver cancer. The present investigation indicated that enhanced tyrosine phosphorylation and tyrosine phosphorylated proteins, with no change in the levels of tyrosine protein phosphatases may contribute to abnormal cellular proliferation during liver carcinogenesis. We have also seen an increase in the expression of proliferating cell nuclear antigen and G1/S cyclins during tumor development.


Asunto(s)
Transformación Celular Neoplásica , Ciclinas/biosíntesis , Regulación Neoplásica de la Expresión Génica , Neoplasias Hepáticas/fisiopatología , Fosfoproteínas Fosfatasas/metabolismo , Fosfotransferasas/metabolismo , Tirosina/metabolismo , Animales , Diferenciación Celular , División Celular , Ciclina G , Ciclina G1 , Masculino , Fosforilación , Ratas , Ratas Wistar
13.
Mol Immunol ; 37(6): 273-80, 2000 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-11000401

RESUMEN

Recent evidence suggests that concanavalin A modulates tyrosyl phosphorylation and activation of a type II PtdIns 4-kinase in rat splenic lymphocytes. However, the regulatory protein tyrosine kinase(s) remain to be elusive. The present manuscript provides evidence that a type II PtdIns 4-kinase associates with p56(lck) in Con A stimulated rat splenic lymphocytes. In vitro phosphorylation studies suggest that p56(lck) regulates phosphorylation and activation of type II PtdIns 4-kinase. Inhibition of p56(lck) activity in vivo has shown to reduce tyrosyl phosphorylation and activation of PtdIns 4-kinase by Con A. These results suggest that p56(lck) may be the physiological regulator of type II PtdIns 4-kinase.


Asunto(s)
1-Fosfatidilinositol 4-Quinasa/metabolismo , Proteína Tirosina Quinasa p56(lck) Específica de Linfocito/metabolismo , Linfocitos/enzimología , Linfocitos/inmunología , 1-Fosfatidilinositol 4-Quinasa/clasificación , Animales , Concanavalina A/farmacología , Activación Enzimática , Técnicas In Vitro , Cinética , Activación de Linfocitos , Linfocitos/efectos de los fármacos , Nocodazol/farmacología , Fosforilación , Ratas , Ratas Wistar , Transducción de Señal , Tirosina/metabolismo
14.
Toxicol Lett ; 116(1-2): 119-30, 2000 Jul 27.
Artículo en Inglés | MEDLINE | ID: mdl-10906429

RESUMEN

Metanil yellow (MY) and Malachite green (MG) are textile dyes, which, despite the ban, occur unscrupulously as food colouring agents. Accordingly they constitute a serious public health hazard and are of sufficient environmental concern. We have earlier reported that both MY and MG have tumor promoting effects on the development of hepatic preneoplastic lesions induced by N-nitrosodiethylamine in rats. In order to understand the possible mechanism(s) by which metanil yellow (MY) and malachite green (MG) promotes liver tumor development, we have studied the tyrosine phosphorylation and protein phosphatases during tumor promotion. We have also investigated the possible overexpression of G1/S cyclins and PCNA during tumor promotion by MY and MG. The present investigation indicates that enhanced tyrosine phosphorylation is associated with no change in levels of tyrosine protein phosphatases. We have also observed an increase in the expression of PCNA and G1/S cyclins during tumor promotion. These factors collectively may contribute to the abnormal cell proliferation during tumor promotion by MY and MG.


Asunto(s)
Compuestos Azo/toxicidad , Ciclinas/biosíntesis , Colorantes de Alimentos/toxicidad , Neoplasias Hepáticas Experimentales/inducido químicamente , Lesiones Precancerosas/inducido químicamente , Antígeno Nuclear de Célula en Proliferación/biosíntesis , Colorantes de Rosanilina/toxicidad , Tirosina/metabolismo , Animales , Dietilnitrosamina , Fase G1 , Neoplasias Hepáticas Experimentales/metabolismo , Masculino , Fosforilación , Lesiones Precancerosas/metabolismo , Ratas , Fase S
15.
Indian J Biochem Biophys ; 36(1): 1-9, 1999 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-10549154

RESUMEN

A PtdIns 4-kinase from rat spleen particulate fraction was purified to homogeneity and its molecular properties were compared with a PtdIns 4-kinase from splenic lymphocytes. The enzyme activity was solubilized from spleen particulate fraction with Triton X-100 and chromatographed sequentially on phosphocellulose, DEAE-sephacel, heparin acrylamide and hydroxyapatite columns. The purified enzyme preparation showed a 55 kDa band on SDS-PAGE with silver staining. Renaturation of the enzyme activity from SDS-PAGE showed that it comigrated with the 55 kDa protein. Characterization of the enzyme showed that it was a type II PtdIns 4-kinase. Polyclonal antibodies raised against PtdIns 4-kinase inhibited the enzyme activity in in vitro assays. Analysis of adult rat tissue particulate fractions on immunoblots showed restricted immunoreactivity among PtdIns 4-kinases. However, the immunoreactivity is conserved in lymphoid tissues from mouse to human, suggesting that lymphoid tissue has a distinct PtdIns 4-kinase. Activation of rat splenocytes with Con A showed two fold increase in PtdIns 4-kinase activity. Comparison of PtdIns 4-kinases from spleen and splenic lymphocytes showed identical chromatographic behaviour, molecular mass, immunoreactivity, K(m) values for PtdIns and inhibition by adenosine.


Asunto(s)
1-Fosfatidilinositol 4-Quinasa/aislamiento & purificación , 1-Fosfatidilinositol 4-Quinasa/antagonistas & inhibidores , 1-Fosfatidilinositol 4-Quinasa/metabolismo , Adenosina/farmacología , Animales , Inhibidores Enzimáticos/farmacología , Humanos , Inmunoquímica , Técnicas In Vitro , Cinética , Linfocitos/enzimología , Ratones , Peso Molecular , Ratas , Ratas Wistar , Bazo/enzimología
16.
Biometrics ; 55(1): 273-6, 1999 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-11318167

RESUMEN

A method has been proposed that gives an exact test and confidence interval for the coefficient of overlap and competition effects. The method is based on Tukey's statistic of nonadditivity. The method is very simple to adopt and can be implemented by regression analysis and analysis of variance programmes in some important cases.


Asunto(s)
Biometría , Intervalos de Confianza , Análisis de Varianza , Funciones de Verosimilitud , Análisis de Regresión
17.
Mol Immunol ; 35(14-15): 935-41, 1998 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-9881689

RESUMEN

Activation of rat splenic lymphocytes by concanavalin A resulted in two-fold increase in Ptdlns 4-kinase activity and rapid tyrosine phosphorylation of the enzyme. The activation kinetics showed a strong correlation with tyrosine phosphorylation state of the enzyme. Characterization of the enzyme activity suggests that it is a type II PtdIns 4-kinase. Kinetic analysis of the enzyme reaction showed three-fold decrease in Km for PtdIns and two-fold increase in Vmax in Con A stimulated cells. These results suggest that a type II PtdIns 4-kinase is an integral component of the early signal transduction machinery during T-cell activation by concanavalin A and is actively regulated by protein tyrosine phosphorylation-dephosphorylation.


Asunto(s)
1-Fosfatidilinositol 4-Quinasa/metabolismo , Concanavalina A/farmacología , Linfocitos/enzimología , Bazo/citología , Tirosina/metabolismo , Animales , Anticuerpos/análisis , Activación Enzimática/efectos de los fármacos , Inhibidores Enzimáticos/farmacología , Genisteína/farmacología , Activación de Linfocitos/efectos de los fármacos , Linfocitos/inmunología , Fosforilación/efectos de los fármacos , Fosfotirosina/inmunología , Pruebas de Precipitina , Proteínas Tirosina Fosfatasas/farmacología , Conejos , Ratas , Ratas Wistar
18.
FEBS Lett ; 441(3): 432-6, 1998 Dec 28.
Artículo en Inglés | MEDLINE | ID: mdl-9891985

RESUMEN

Regulation of phosphatidylinositol 4-kinase (PtdIns 4-kinase) by protein tyrosine phosphorylation has been indirect and the effects of phosphorylation are debatable. Rat splenic type II PtdIns 4-kinase was phosphorylated in vitro with protein tyrosine kinases from Con A stimulated splenic lymphocytes. Stoichiometric analysis showed one mole of phosphate was incorporated per mole of PtdIns 4-kinase. Tyrosine phosphorylation increased the enzyme activity by 3-fold. Kinetic analysis showed a reduction in Km for PtdIns and an increase in Vmax. Dephosphorylation with protein phosphotyrosine phosphatase abolished the activation of PtdIns 4-kinase while protein phosphatase 2A had no effect. Protein tyrosine phosphorylation and activation of PtdIns 4-kinase appear to be tissue specific.


Asunto(s)
1-Fosfatidilinositol 4-Quinasa/metabolismo , Bazo/enzimología , Tirosina/metabolismo , Animales , Concanavalina A/farmacología , Activación Enzimática , Linfocitos/citología , Linfocitos/efectos de los fármacos , Linfocitos/enzimología , Fosforilación , Proteínas Tirosina Quinasas/metabolismo , Ratas , Bazo/citología
19.
Genetics ; 129(3): 763-71, 1991 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-1752419

RESUMEN

The effects of a series of eight, 50 base pair internal deletions in the 5' region upstream of the proximal transcription start site of the Adh gene of Drosophila melanogaster were examined in a quantitative assay. Mixtures of two plasmids, one bearing a deleted gene, the other with an intact reference gene, were injected into alcohol dehydrogenase-negative embryos. Third instar larvae of the injected generation were assayed for relative alcohol dehydrogenase enzyme activity. Quantitative analysis of the eight deletions indicated that two regions were required for any detectable enzyme activity and one region was required for appropriate tissue specificity. The remaining five deletions significantly decreased, but did not eliminate activity. When the deleted genes were placed on a plasmid with an intact reference gene, activities of all but one deletion were restored to levels equivalent to that of the intact reference gene (regardless of orientation). This restoration of activity did not occur when the regulatory region of the intact gene was replaced with the Hsp70 heat shock promoter nor when the 50-base pair deletion encompassed the region that includes the TATA sequence. The fact that seven of the eight deleted genes express activity in the presence of a reference gene on the same plasmid suggests that the deleted gene is controlled by regulatory elements in the reference gene. Further, these regulatory elements exhibit no preference for their own, more proximate, promoter.


Asunto(s)
Alcohol Deshidrogenasa/genética , Drosophila melanogaster/genética , Animales , Clonación Molecular , Análisis Mutacional de ADN , Drosophila melanogaster/crecimiento & desarrollo , Regulación de la Expresión Génica , Proteínas de Choque Térmico/genética , Larva , Plásmidos , Regiones Promotoras Genéticas , Secuencias Reguladoras de Ácidos Nucleicos , Mapeo Restrictivo
20.
Biochim Biophys Acta ; 1080(1): 11-8, 1991 Oct 11.
Artículo en Inglés | MEDLINE | ID: mdl-1657176

RESUMEN

A membrane-bound phosphatidylinositol 4-kinase (PtdIns kinase) has been purified to apparent homogeneity from human erythrocytes. Enzyme activity was solubilized from urea-KCl-stripped, inside-out membrane vesicles by 3% Triton X-100. Purification to apparent homogeneity was accomplished by cation-exchange chromatography on phosphocellulose, followed by heparin-acrylamide chromatography. This resulted in a nearly 3900-fold purification of PtdIns kinase activity to a specific activity of 44 nmol min-1 mg-1. The purified enzyme has an Mr of 59,000 on silver-stained SDS-PAGE; however, many preparations also contain 54 kDa and 50 kDa proteins which are related to the 59 kDa protein and have PtdIns kinase activity. Kinetic analysis of the PtdIns kinase indicate apparent Km values of 40 and 35 microM for phosphatidylinositol and ATP, respectively. The purified enzyme has been reconstituted into phospholipid liposomes and shown to phosphorylate phosphatidylinositol.


Asunto(s)
Membrana Eritrocítica/enzimología , Fosfotransferasas (Aceptor de Grupo Alcohol) , Fosfotransferasas/aislamiento & purificación , Electroforesis en Gel de Poliacrilamida , Humanos , Cinética , Liposomas , Mapeo Peptídico , Fosfatidilinositoles/metabolismo , Fosfotransferasas/antagonistas & inhibidores , Fosfotransferasas/metabolismo , Tripsina
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