13 results on '"D. Alok"'
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2. Effects of controlled delivery and acute injections of LHRHa on bullseye puffer fish (Sphoeroides annulatus) spawning
- Author
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Neil J. Duncan, G.A. Rodriguez M. de O., D. Alok, and Y. Zohar
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medicine.medical_specialty ,biology ,medicine.drug_class ,Fish farming ,media_common.quotation_subject ,Aquatic Science ,biology.organism_classification ,Animal science ,Human fertilization ,Endocrinology ,Internal medicine ,Sphoeroides annulatus ,medicine ,Sexual maturity ,Gonadotropin ,Reproduction ,Luteinizing hormone ,Tetraodontidae ,media_common - Abstract
Mature bullseye puffer (Sphoeroides annulatus) fish were caught and taken into captivity. Fish with a mean oocyte diameter greater than 0.45 mm were divided equally into three experimental groups (n=11) that were treated with a saline injection (control), multiple injections of luteinizing hormone-releasing hormone analogue (LHRHa) (day 0—20 A gk g � 1 , day 2—40 A gk g � 1 , day 4— 80 A gk g � 1 , day 6—160 A gk g � 1 ) and a single administration of slow-release ethylene vinyl acetate (EVAc) co-polymer implants containing the identical LHRHa (day 0—75 Ag per fish 800 g). A total of 82% of the fish spawned in each of the two LHRHa groups (injection and implant) compared to just 18% in the control group. The majority of the fish treated with LHRHa, eight in the injection group and nine in the implant group, spawned during the first week after administration. There were no significant differences in mean egg size (group means 0.64–0.71 mm) and percentage fertilization (group means 90.2–97.3%) among the LHRHa-treated groups and when compared with the control fish that received saline injection and fish that ovulated naturally without any treatment. The successful spawning using LHRHa-based spawning protocols is an important step in the development of the culture of the bullseye puffer. D 2003 Elsevier Science B.V. All rights reserved.
- Published
- 2003
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3. Bias-Temperature-Stress Induced Mobility Improvement in 4H-SiC MOSFETs
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T. P. Chowt, K. Chattyt, R. J. Gutmannt, E. Arnoldi, and D. Alok
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Materials science ,Condensed matter physics ,Oxide ,Field effect ,law.invention ,Ion ,Stress (mechanics) ,chemistry.chemical_compound ,Capacitor ,chemistry ,law ,MOSFET ,Order of magnitude ,Voltage - Abstract
In this work, we report on an instability which affects the field effect mobility in 4HSiC MOSFETs. The devices (MOSFETs and capacitors) were subjected to a biastemperature stress (BTS) for 30 minutes at 150°C at stress voltages corresponding to oxide fields upto 1MV/cm. Following a positive BTS(i.e. gate voltage positive), the field effect mobility increased by upto two orders of magnitude from the original value; upon application of a negative BTS to the MOSFET, the device characteristics degraded to the unstressed state. The high mobility state could be recovered by a positive BTS and was reversible with repeated bias stressing. An explanation of this phenomenon is proposed based on the effect of interfacial ions on the dependence of both trapped charge and inversion charge densities on gate bias.
- Published
- 1999
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4. D-Lys6 Salmon Gonadotropin-Releasing Hormone Analogue-Domperidone Induced Ovulation in Clarias batrachus (L.)
- Author
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D. ALOK
- Subjects
Ecology ,Aquatic Science ,Food Science - Abstract
A single intramuscular injection of D-Lys6 salmon gonadotropin-releasing hormone analogue (sGnRH-A) at a dose of 50 µ,g-kg·1 body weight (b. wt.) in combination with domperidone at 5 mg,kg·1 b. wt. induced final maturation and ovulation in Clarias batrachus. The fish did not spawn spontaneously but released eggs on handstripping. Fertilization and hatching rates were 70-80% and 50-60%, respectively. sGnRH-A alone did not induce ovulation at a dose as high as 500 µg,kg·1 b. wt. Comparable results in terms of spawning, fertilization and hatching were obtained when pituitary extract was injected at a dose of 40 mg,kg·1 b. wt.
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- 1995
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5. Symbiotic nitrogen fixation and endophytic bacterial community structure in Bt-transgenic chickpea (Cicer arietinum L).
- Author
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Alok D, Annapragada H, Singh S, Murugesan S, and Singh NP
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- Biomass, Ecosystem, Genome, Plant genetics, Plant Root Nodulation genetics, Plant Roots genetics, Plant Roots microbiology, Transgenes genetics, Cicer genetics, Cicer metabolism, Cicer microbiology, Mesorhizobium physiology, Nitrogen Fixation, Plant Physiological Phenomena, Plants, Genetically Modified, Symbiosis
- Abstract
Symbiotic nitrogen fixation (SNF) of transgenic grain legumes might be influenced either by the site of transgene integration into the host genome or due to constitutive expression of transgenes and antibiotic-resistant marker genes. The present investigation confirmed proper nodulation of five tested Bt-chickpea events (IPCa2, IPCa4, IPCT3, IPCT10, and IPCT13) by native Mesorhizobium under field environment. Quantitative variations for nodulation traits among Bt-chickpea were determined and IPCT3 was found superior for nodule number and nodule biomass. Diversity, as well as richness indices, confirmed the changes in bacterial community structure of root and root-nodules from Bt-chickpea events IPCa2 and IPCT10. Especially, Gram-positive bacteria belonging to Firmicutes and Actinobacteria were selectively eliminated from root colonization of IPCa2. Richness indices (CHAO1 and ACE) of the root-associated bacterial community of IPCa2 was 13-14 times lesser than that of parent cv DCP92-3. Root nodule associated bacterial community of IPCT10 was unique with high diversity and richness, similar to the roots of non-Bt and Bt-chickpea. It indicated that the root nodules of IPCT10 might have lost their peculiar characteristics and recorded poor colonization of Mesorhizobium with a low relative abundance of 0.27. The impact of Bt-transgene on bacterial community structure and nodulation traits should be analyzed across the years and locations to understand and stabilize symbiotic efficiency for ecosystem sustainability.
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- 2020
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6. Fine Needle Aspiration Cytology versus Fine Needle Capillary Sampling in Cytological Diagnosis of Thyroid Lesions.
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Pinki P, Alok D, Ranjan A, and Nanak Chand M
- Abstract
Background and Objectives: Fine needle aspiration cytology (FNAC) is an established out- patient procedure used in primary diagnosis of palpable thyroid lesions. A modified technique fine needle capillary sampling (FNCS) obviates the need of suction, is less painful, patient friendly and reported to overcome the problem of inadequate and bloody specimens. The aim of our study was to compare the efficacy and quality of FNCS with that of conventional FNAC in the lesions of thyroid., Methods: One hundred patients, presenting between January 2011 to December 2012 at Cytopathology Department of M M Institute of Medical Sciences and Research, Mullana, with diffuse and nodular thyroid lesions were enrolled with both the techniques being executed on the patients, beginning with FNA followed by FNCS. The smears were scored using five objective parameters i.e. background blood, cellular material, cellular degeneration, cellular trauma, and retention of appropriate architecture, in a single blind setting by a cyto-pathologist. The results were analyzed using Student's test for paired data and chi- square analysis., Results: A highly significant differences (P<0.001) in favor of FNCS was observed for the background blood, cellular material and retention of architecture while total score favored FNA for cellular degeneration and degree of cellular trauma. Total scores and average score per case for FNCS was significantly better (P<0.001) than FNA. FNCS technique yielded more diagnostically superior and lesser number of unsatisfactory smears whereas greater number of diagnostically adequate samples was obtained by FNA technique., Conclusion: FNCS offers more number of diagnostically better quality smears. Both techniques could be supplementary on many occasions and substitutive on a few. Combination of the two techniques could offer better diagnostic accuracy.
- Published
- 2015
7. Current issues in health policy: a primer for the orthopaedic surgeon.
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Sharan D A, Genuario J, Mehta S, Kusuma S, Ranawat A, Nunley R, and Weinstein SL
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- Cost Savings, Health Policy legislation & jurisprudence, Humans, Liability, Legal, Medicare legislation & jurisprudence, Orthopedics legislation & jurisprudence, Health Policy economics, Medicare economics, Orthopedics economics, Quality of Health Care, Reimbursement Mechanisms
- Abstract
Political, social, and economic forces occupy an increasingly larger role in health care. It is essential that orthopaedic surgeons become familiar with the ever-changing landscape within which they practice. Greater comprehension of the current issues in health policy will enable practitioners to appreciate these issues and understand the importance of the involvement of the AAOS in the political process. Five topics in particular will continue to have a great impact on the practice of orthopaedic surgery: the flawed Medicare payment formula, implementation of a pay-for-performance program, the creation of gainsharing agreements between hospitals and physicians, the medical liability crisis, and the importance of advocacy with the political action committee of the AAOS.
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- 2007
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8. Recombinant perciform GnRH-R activates different signaling pathways in fish and mammalian heterologous cell lines.
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Alok D, Kumar RS, Trant JM, and Zohar Y
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- Animals, Bass, Cell Line, Chickens, Chlorocebus aethiops, Genes, Reporter, Receptors, LHRH genetics, Recombinant Proteins genetics, Recombinant Proteins metabolism, Salmon, Species Specificity, Fishes, Gonadotropin-Releasing Hormone pharmacology, Receptors, LHRH metabolism, Signal Transduction drug effects
- Abstract
Perciforms have three forms of gonadotropin-releasing hormone (GnRH) in their brain. All three GnRHs are potent secretogogues for luteinizing hormone (LH) from the pituitary. The pivotal role of GnRH-R-GnRH interactions in reproductive homeostasis is well established; however, there is a paucity of information on how a GnRH-R responds to the three endogenous GnRH forms in a perciform species. In this study, a recombinant pituitary GnRH-R from striped bass (stb) was expressed in a mammalian cell line (COS-7) and a fish cell line (CHSE-214). Activation of the signaling pathways was monitored by reporter gene (luciferase) based assays, which were specific for cAMP-PKA or Ca 2+/calmodulin kinase (activated via c-fos promoter) signaling pathways. The stbGnRH-R expressed in two different cell lines triggered different downstream signaling in response to the treatments with chicken (c) GnRH II. Interestingly, when endogenous GnRHs were used in combinations, the luciferase activity was significantly attenuated in transfected CHSE-214 cells.
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- 2001
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9. Characterization of a pituitary GnRH-receptor from a perciform fish, Morone saxatilis: functional expression in a fish cell line.
- Author
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Alok D, Hassin S, Sampath Kumar R, Trant JM, Yu K, and Zohar Y
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- Amino Acid Motifs, Amino Acid Sequence, Analysis of Variance, Animals, Bass metabolism, Cell Line, Cloning, Molecular, Embryo, Nonmammalian, Female, Genes, Reporter, Molecular Sequence Data, Phylogeny, RNA, Messenger genetics, RNA, Messenger metabolism, Receptors, LHRH chemistry, Salmon, Sequence Alignment, Bass genetics, Pituitary Gland physiology, Receptors, LHRH genetics, Receptors, LHRH metabolism
- Abstract
Gonadotropin-releasing hormones (GnRHs) bind to the specific receptor present on the gonadotrophs to activate the synthesis and release of gonadotropins (follicle stimulating hormone or FSH and luteinizing hormone or LH), which in turn control gonadal maturation, gametogenesis and gamete release. Perciform species have three endogenous GnRHs. The main objective of this study was to characterize the gonadotropin-releasing hormone receptor (GnRH-R) present in the pituitary of a perciform species, striped bass (Morone saxatilis) and demonstrate how it interacts with its potential ligand. In this study, a cDNA for GnRH-R from the pituitaries of striped bass was cloned. The cloned cDNA has an open reading frame (ORF) that codes for a 419 amino acids peptide. Like other G-protein coupled receptors including the non-mammalian GnRH-Rs, the peptide has seven putative transmembrane domains and a C-terminal tail. Comparative analysis of the amino acid sequence of striped bass (stb) GnRH-R shows 38-87% similarity with the known GnRH-Rs. A Northern blot analysis revealed a single GnRH-R transcript in the pituitary; however, its expression in various extrapituitary tissues was demonstrated by a reverse-transcription-PCR (RT-PCR). Functionally, upon induction by endogenous forms of GnRHs (seabream, chicken II and salmon GnRHs) and a mammalian GnRH-agonist, the recombinant stbGnRH-R mediated a reporter gene (luciferase) activity in a fish cell line (CHSE-214). A real-time relative quantitation method established that significantly higher (P<0.05) levels of stbGnRH-R mRNA were present in the pituitaries of striped bass with advanced stages of ovarian development, compared to the pituitaries of fish with less developed ovaries.
- Published
- 2000
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10. Cloning and functional expression of a thyrotropin receptor from the gonads of a vertebrate (bony fish): potential thyroid-independent role for thyrotropin in reproduction.
- Author
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Kumar RS, Ijiri S, Kight K, Swanson P, Dittman A, Alok D, Zohar Y, and Trant JM
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- Amino Acid Sequence, Animals, Bass physiology, COS Cells, Cattle, Cloning, Molecular, DNA, Complementary, Female, Genes, Reporter, Humans, In Situ Hybridization, Male, Molecular Sequence Data, Ovary ultrastructure, Phylogeny, RNA, Messenger metabolism, Receptors, Thyrotropin chemistry, Receptors, Thyrotropin metabolism, Reverse Transcriptase Polymerase Chain Reaction, Sequence Alignment, Sequence Analysis, DNA, Testis ultrastructure, Thyroid Gland metabolism, Bass genetics, Ovary physiology, Receptors, Thyrotropin genetics, Testis physiology, Thyrotropin metabolism
- Abstract
The thyroid stimulating hormone receptor (TSHR) mediates the pituitary control of the development, growth and function of the thyroid. The expression of the gene encoding this receptor is known only in the thyroid, lymphocytes, fibroblasts, retro-orbital tissue and fat cells. We have cloned a TSHR from the gonads of a non-mammalian vertebrate, a bony fish (striped bass, Morone saxatilis) in the course of our search for gonadotropin receptors (follicle stimulating hormone receptor, FSHR and luteinizing hormone receptor, LHR). RT-PCR analysis demonstrated that the striped bass TSHR (stbTSHR) transcripts were abundant in both the thyroid and gonads and detectable in skeletal muscle, heart and brain tissues. The stbTSHR cDNA encoded a 779-amino acid glycoprotein hormone receptor with much higher homology (57-59%) to the mammalian TSH receptors than the mammalian LH receptors (47-49%) and FSH receptors (47%), and salmon and catfish gonadotropin receptors (42-45%). There was a TSHR-specific insertion in the extracellular domain as seen in mammalian receptors. Moreover, PCR analysis of genomic DNA indicated the absence of the LHR-specific intron in the striped bass TSHR gene. Recombinant stbTSHR expressed in COS1 cells activated reporter genes (luciferase) driven by either a cAMP response element or the c-fos promoter in response to bovine TSH, stbLH or hCG, but not human FSH. In situ hybridization studies revealed the presence of stbTSHR transcripts in the gametes but not in the follicular cells. This pattern of expression is unique and suggests a direct, albeit unknown, role for TSH in gamete physiology.
- Published
- 2000
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11. Multiple GnRHs present in a teleost species are encoded by separate genes: analysis of the sbGnRH and cGnRH-II genes from the striped bass, Morone saxatilis.
- Author
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Chow MM, Kight KE, Gothilf Y, Alok D, Stubblefield J, and Zohar Y
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- Amino Acid Sequence, Animals, Base Sequence, Brain metabolism, Cloning, Molecular, DNA Primers genetics, DNA, Complementary genetics, Gonadotropin-Releasing Hormone analogs & derivatives, Male, Molecular Sequence Data, Promoter Regions, Genetic, Sequence Homology, Amino Acid, Transcription, Genetic, Bass genetics, Gonadotropin-Releasing Hormone genetics
- Abstract
GnRH is a neuropeptide which plays an essential role in the control of reproductive fitness for all vertebrates. Increasing evidence suggests that multiple forms of GnRH may exist in most vertebrate brains. Southern blot analysis of the three GnRHs known to be present in perciform fish, the seabream (sb)GnRH, the salmon(s) GnRH and the chicken (c) GnRH-II, demonstrates that each is present as a single gene copy in the genome of the striped bass, Morone saxatilis. In order to investigate the physiological consequences of multiple GnRHs in a single vertebrate species, we have isolated and characterized two of the GnRH genes, those for sbGnRH and cGnRH-II. Computer analysis of 3.5 kb of sequence upstream of the sbGnRH gene reveals a number of consensus DNA binding sites which implicate steroids, such as estrogen and glucocorticoids, and the steroidogenic transcription factor, SF-1, as being involved in the regulation of sbGnRH gene expression. Sequence analysis of the cGnRH-II gene reveals evidence of multiple promoters. Expression studies using (1) solution hybridization-RNAse protection mapping with several RNA probes directed at various regions of the proGnRH gene, (2) primer extension assays using two specific oligonucleotide primers, and (3) reverse transcription PCR with several oligonucleotide primers on cGnRH-II transcripts demonstrate that the cGnRH-II gene initiates transcription at numerous sites using a TATA-less promoter within the brains of sexually mature striped bass. This study is the first to characterize and compare the promoter structures of two GnRH genes present in a single vertebrate species.
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- 1998
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12. Binding of factor VIIa to tissue factor induces alterations in gene expression in human fibroblast cells: up-regulation of poly(A) polymerase.
- Author
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Pendurthi UR, Alok D, and Rao LV
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- Base Sequence, Cell Line, Factor VIIa genetics, Fibroblasts metabolism, Humans, Molecular Sequence Data, Protein Binding genetics, Thromboplastin genetics, Up-Regulation, Factor VIIa metabolism, Polynucleotide Adenylyltransferase genetics, Thromboplastin metabolism
- Abstract
Tissue factor (TF) is the cellular receptor for an activated form of clotting factor VII (VIIa) and the binding of factor VII(a) to TF initiates the coagulation cascade. Sequence and structural patterns extracted from a global alignment of TF confers homology with interferon receptors of the cytokine receptor super family. Several recent studies suggested that TF could function as a genuine signal transducing receptor. However, it is unknown which biological function(s) of cells are altered upon the ligand, VIIa, binding to TF. In the present study, we examined the effect of VIIa binding to cell surface TF on cellular gene expression in fibroblasts. Differential mRNA display PCR technique was used to identify transcriptional changes in fibroblasts upon VIIa binding to TF. The display showed that VIIa binding to TF either up or down-regulated several mRNA species. The differential expression of one such transcript, VIIa-induced up-regulation, was confirmed by Northern blot analysis. Isolation of a full-length cDNA corresponding to the differentially expressed transcript revealed that VIIa-up-regulated gene was poly(A) polymerase. Northern blot analysis of various carcinomas and normal human tissues revealed an over expression of PAP in cancer tissues. Enhanced expression of PAP upon VIIa binding to tumor cell TF may potentially play an important role in tumor metastasis.
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- 1997
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13. Translational fusion of heat labile enterotoxin chain B and beta-subunit of human chorionic gonadotropin: periplasmic expression in Escherichia coli and its immunogenicity.
- Author
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Pillai D, Dixit A, Alok D, and Garg LC
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- Animals, Bacterial Toxins immunology, Bacterial Toxins metabolism, Chorionic Gonadotropin, beta Subunit, Human immunology, Chorionic Gonadotropin, beta Subunit, Human metabolism, Cloning, Molecular, Cytoplasm metabolism, Enterotoxins immunology, Enterotoxins metabolism, Escherichia coli, Hot Temperature, Humans, Mice, Mice, Inbred BALB C, Protein Biosynthesis, Receptors, Cell Surface metabolism, Recombinant Fusion Proteins genetics, Recombinant Fusion Proteins immunology, Recombinant Fusion Proteins metabolism, Bacterial Toxins genetics, Chorionic Gonadotropin, beta Subunit, Human genetics, Enterotoxins genetics, Escherichia coli Proteins
- Abstract
A fusion gene was constructed consisting of heat labile enterotoxin chain B (LTB) of E. coli genetically linked at its C-terminus to the beta-subunit of human chorionic gonadotropin in translational fusion, under the control of tac promoter and LTB signal sequence. Expression of the fusion gene (about 5 microgram/ml) in E. coli was confirmed by immunoblot analysis using both anti-LTB and anti-betahCG polyclonal antibodies. The fusion protein was efficiently processed and exported to the periplasmic space. LTB in the fusion protein retained its ability to bind to GM1 ganglioside receptor. Mice immunized with the fusion protein produce antibodies that recognize recombinant betahCG and the native hCG suggesting its potential use as a contraceptive vaccine.
- Published
- 1996
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