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Makkar K, Sharma Y, Batta A. Endocrinological profile of patients with cardiogenic shock. Indian Heart J 2020. [DOI: 10.1016/j.ihj.2020.11.059] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022] Open
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Batta A, Mahesh KV, Prabhat N, Shree R, Goyal MK, Ahuja CK, Rebello A, Tandyala N, Goyal A, Choudhary A, Goyal G, Modi M, Singh P. Newer magnetic resonance imaging techniques in neurocysticercosis. Neuroradiol J 2020; 33:538-544. [PMID: 32842861 PMCID: PMC7788671 DOI: 10.1177/1971400920949394] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
Abstract
INTRODUCTION The definitive diagnosis of neurocysticercosis continues to be challenging. We evaluate the role of newer magnetic resonance imaging techniques including constructive interference in steady state, susceptibility-weighted imaging, arterial spin labelling and magnetic resonance spectroscopy in the diagnosis of neurocysticercosis. AIMS AND OBJECTIVES To study the utility of newer magnetic resonance imaging sequences in the diagnosis of neurocysticercosis. PATIENTS AND METHODS Eighty-five consecutive patients with neurocysticercosis attending a tertiary care hospital and teaching centre in northern India were included in the study. The diagnosis of neurocysticercosis was made by the Del Brutto criteria. All patients received treatment according to standard guidelines and were followed at 3-month intervals. The following magnetic resonance sequences were performed at baseline: T1 and T2-weighted axial sequences; T2 fluid-attenuated inversion recovery axial sequences; diffusion-weighted imaging; susceptibility-weighted imaging; pre and post-contrast T1-weighted imaging; heavily T2-weighted thin sections (constructive interference in steady state); arterial spin labelling (n = 19); and magnetic resonance spectroscopy (n = 24). RESULTS The mean (±SD) age was 29.4 ± 12.9 years and 76.5% were men. Seizures were the commonest symptom (89.4%) followed by headache (24.3%), encephalitis (9.4%) and raised intracranial pressure (9.4%). Scolex could be visualised in 43.7%, 55.5% and 61.2% of neurocysticercosis patients using conventional, susceptibility-weighted angiography and constructive interference in steady state imaging sequences, respectively. Susceptibility-weighted angiography and constructive interference in steady state images resulted in significantly higher (P < 0.01) visualisation of scolex compared to conventional sequences. CONCLUSION Newer magnetic resonance imaging modalities have a lot of promise for improving the radiological diagnosis of neurocysticercosis.
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Affiliation(s)
- Akash Batta
- Department of Internal Medicine, Post Graduate Institute of Medical Education and Research, India
| | - Karthik Vinay Mahesh
- Department of Neurology, Post Graduate Institute of Medical Education and Research, India
| | - Nandita Prabhat
- Department of Neurology, Post Graduate Institute of Medical Education and Research, India
| | - Ritu Shree
- Department of Neurology, Post Graduate Institute of Medical Education and Research, India
| | - Manoj K Goyal
- Department of Neurology, Post Graduate Institute of Medical Education and Research, India
| | - Chirag K Ahuja
- Department of Radiodiagnosis and Imaging, Post Graduate Institute of Medical Education and Research, India
| | - Alex Rebello
- Department of Neurology, Post Graduate Institute of Medical Education and Research, India
| | - Naresh Tandyala
- Department of Neurology, Post Graduate Institute of Medical Education and Research, India
| | - Abeer Goyal
- Department of Neurology, Post Graduate Institute of Medical Education and Research, India
| | - Aditya Choudhary
- Department of Neurology, Post Graduate Institute of Medical Education and Research, India
| | - Gunjan Goyal
- Department of Medical Parasitology, Post Graduate Institute of Medical Education and Research, India
| | - Manish Modi
- Department of Neurology, Post Graduate Institute of Medical Education and Research, India
| | - Paramjeet Singh
- Department of Radiodiagnosis and Imaging, Post Graduate Institute of Medical Education and Research, India
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Batta A, Panda P. Atrial fibrillation: Angiographic profiles and its relationship with coronary artery disease. Indian Heart J 2019. [DOI: 10.1016/j.ihj.2019.11.029] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022] Open
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Kanabar K, Batta A, Debi U, Rohit MK. Large ductus arteriosus aneurysm in an elderly patient. IHJ Cardiovascular Case Reports (CVCR) 2019. [DOI: 10.1016/j.ihjccr.2019.12.007] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/07/2023]
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Uitslag-Doolaard H, Roelofs F, Pacio J, Batta A. Experiment design to assess the inter-wrapper heat transfer in LMFR. Nuclear Engineering and Design 2019. [DOI: 10.1016/j.nucengdes.2018.11.019] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
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Agarwala R, Batta A, Suryadevera V, Kumar V, Sharma V, Rana SS. Spontaneous tumour lysis syndrome in hepatocellular carcinoma presenting with hypocalcemic tetany: An unusual case and systematic literature review. Clin Res Hepatol Gastroenterol 2017; 41:e29-e31. [PMID: 27743982 DOI: 10.1016/j.clinre.2016.09.003] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/11/2016] [Revised: 08/22/2016] [Accepted: 09/02/2016] [Indexed: 02/04/2023]
Abstract
Tumour lysis syndrome is an oncological emergency which is usually seen following chemotherapy for rapidly proliferating haematological malignancies. Spontaneous tumour lysis syndrome is rare in solid tumour and even rarer with hepatocellular carcinoma (HCC). Tumour lysis syndrome in the setting of HCC is usually reported as a consequence of therapeutic interventions like sorafenib administration or trans-arterial chemoembolization. We report about a case of a young lady with chronic hepatitis B related HCC who developed spontaneous tumour lysis syndrome and presented with hypocalcemic tetany. We also compare this case with the previously reported cases of spontaneous tumour lysis syndrome in hepatocellular carcinoma.
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Affiliation(s)
- Roshan Agarwala
- Department of Gastroenterology, Postgraduate Institute of Medical Education and Research, India
| | - Akash Batta
- Department of Internal Medicine, Postgraduate Institute of Medical Education and Research, India
| | - Varun Suryadevera
- Department of Internal Medicine, Postgraduate Institute of Medical Education and Research, India
| | - Vivek Kumar
- Department of Nephrology, Postgraduate Institute of Medical Education and Research, India
| | - Vishal Sharma
- Department of Gastroenterology, Postgraduate Institute of Medical Education and Research, India.
| | - Surinder Singh Rana
- Department of Gastroenterology, Postgraduate Institute of Medical Education and Research, India
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Rohde M, Peeters JWR, Pucciarelli A, Kiss A, Rao YF, Onder EN, Muehlbauer P, Batta A, Hartig M, Chatoorgoon V, Thiele R, Chang D, Tavoularis S, Novog D, McClure D, Gradecka M, Takase K. A Blind, Numerical Benchmark Study on Supercritical Water Heat Transfer Experiments in a 7-Rod Bundle. Journal of Nuclear Engineering and Radiation Science 2016. [DOI: 10.1115/1.4031949] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Heat transfer in supercritical water reactors (SCWRs) shows a complex behavior, especially when the temperatures of the water are near the pseudocritical value. For example, a significant deterioration of heat transfer may occur, resulting in unacceptably high cladding temperatures. The underlying physics and thermodynamics behind this behavior are not well understood yet. To assist the worldwide development in SCWRs, it is therefore of paramount importance to assess the limits and capabilities of currently available models, despite the fact that most of these models were not meant to describe supercritical heat transfer (SCHT). For this reason, the Gen-IV International Forum initiated the present blind, numerical benchmark, primarily aiming to show the predictive ability of currently available models when applied to a real-life application with flow conditions that resemble those of an SCWR. This paper describes the outcomes of ten independent numerical investigations and their comparison with wall temperatures measured at different positions in a 7-rod bundle with spacer grids in a supercritical water test facility at JAEA. The wall temperatures were not known beforehand to guarantee the blindness of the study. A number of models have been used, ranging from a one-dimensional (1-D) analytical approach with heat transfer correlations to a RANS simulation with the SST turbulence model on a mesh consisting of 62 million cells. None of the numerical simulations accurately predicted the wall temperature for the test case in which deterioration of heat transfer occurred. Furthermore, the predictive capabilities of the subchannel analysis were found to be comparable to those of more laborious approaches. It has been concluded that predictions of SCHT in rod bundles with the help of currently available numerical tools and models should be treated with caution.
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Affiliation(s)
- M. Rohde
- Delft University of Technology, Mekelweg 15, Delft 2629 JB, The Netherlands e-mail:
| | - J. W. R. Peeters
- Delft University of Technology, Mekelweg 15, Delft 2629 JB, The Netherlands
| | - A. Pucciarelli
- University of Pisa, Largo Lucio Lazzarino 2, 56126 Pisa, Italy
| | - A. Kiss
- BME NTI, Muegyetem rkp. 9 R bld. 317/7a, Budapest 1111, Hungary
| | - Y. F. Rao
- CNL, 286 Plant Road, Chalk River, ON K0J 1J0, Canada
| | - E. N. Onder
- CNL, 286 Plant Road, Chalk River, ON K0J 1J0, Canada
| | - P. Muehlbauer
- Research Centre Rez Ltd., Hlavní 130, Rez 250 68, Czech Republic
| | - A. Batta
- KIT-IKET, Hermann-von-Helmholtz-Platz 1, Karlsruhe 76344, Germany
| | - M. Hartig
- KIT-IKET, Hermann-von-Helmholtz-Platz 1, Karlsruhe 76344, Germany
| | - V. Chatoorgoon
- University of Manitoba, 75A Chancellors Circle, Winnipeg, MB R3T 5V6, Canada
| | - R. Thiele
- KTH Royal Institute of Technology, Roslagstullsbacken 21, Stockholm 106 91, Sweden
| | - D. Chang
- University of Ottawa, 161 Louis Pasteur, Ottawa, ON K1N6N5, Canada
| | - S. Tavoularis
- University of Ottawa, 161 Louis Pasteur, Ottawa, ON K1N6N5, Canada
| | - D. Novog
- McMaster University, Somestreet 1, Hamilton, ON 333AS, Canada
| | - D. McClure
- McMaster University, Somestreet 1, Hamilton, ON 333AS, Canada
| | - M. Gradecka
- Warsaw University of Technology, ul. nowowiejska 21/25, Warsaw 00665, Poland
| | - K. Takase
- Japan Atomic Energy Agency, 2-4 Shirakata, Tokai, Naka Ibaraki, Ibaraki-ken 319-1195, Japan
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Batta A, Class A, Litfin K, Wetzel T, Moreau V, Massidda L, Thomas S, Lakehal D, Angeli D, Losi G, Mooney K, Van Tichelen K. Experimental and numerical investigation of liquid-metal free-surface flows in spallation targets. Nuclear Engineering and Design 2015. [DOI: 10.1016/j.nucengdes.2014.11.009] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
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Cheng X, Batta A, Bandini G, Roelofs F, Van Tichelen K, Gerschenfeld A, Prasser M, Papukchiev A, Hampel U, Ma W. European activities on crosscutting thermal-hydraulic phenomena for innovative nuclear systems. Nuclear Engineering and Design 2015. [DOI: 10.1016/j.nucengdes.2014.11.007] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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Batta A, Cho JH, Class A, Hwang IS. CFD ANALYSIS OF HEAVY LIQUID METAL FLOW IN THE CORE OF THE HELIOS LOOP. Nuclear Engineering and Technology 2010. [DOI: 10.5516/net.2010.42.6.656] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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Fazio C, Gröschel F, Wagner W, Thomsen K, Smith B, Stieglitz R, Zanini L, Guertin A, Cadiou A, Henry J, Agostini P, Dai Y, Heyck H, Dementjev S, Panebianco S, Almazouzi A, Eikenberg J, Letourneau A, Toussaint J, Janett A, Perret C, Joray S, Patorski J, Leung W, Meloni P, Turroni P, Zucchini A, Benamati G, Konys J, Auger T, Gessi A, Gorse D, Serre I, Terlain A, Vogt JB, Batta A, Class A, Cheng X, Fellmoser F, Daubner M, Gnieser S, Grötzbach G, Milenkovic R, Latgé C, Knebel J. The MEGAPIE-TEST project: Supporting research and lessons learned in first-of-a-kind spallation target technology. Nuclear Engineering and Design 2008. [DOI: 10.1016/j.nucengdes.2007.11.006] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
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Stieglitz R, Daubner M, Batta A, Lefhalm CH. Turbulent heat mixing of a heavy liquid metal flow in the MEGAPIE target geometry—The heated jet experiment. Nuclear Engineering and Design 2007. [DOI: 10.1016/j.nucengdes.2007.02.016] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
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Abstract
The present paper gives a brief literature review on turbulent heat transfer in heavy liquid metals (HLM), especially liquid lead-bismuth eutectic (LBE). Some models available in the open literature on heat transfer and turbulent Prandtl number are assessed. In addition, CFD analysis is carried out for circular tube geometries. The effect of turbulence models, mesh structure and turbulent Prandtl number on the numerical results is studied. Application of ε-type turbulence models with scalable wall function shows less dependence of the numerical results on mesh structure than the ω-type turbulence models with automatic wall treatment. The turbulent Prandtl number affects strongly the heat transfer performance. Comparison between the CFD results, heat transfer correlations and heat transfer test data reveals a decrease in turbulent Prandtl number by increasing Reynolds number. Based on the results achieved, recommendations are made on correlations of heat transfer and turbulent Prandtl number for LBE flows.
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Affiliation(s)
- X. Cheng
- Institute of Nuclear and Energy Technology, Karlsruhe, Germany
| | - A. Batta
- Institute of Nuclear and Energy Technology, Karlsruhe, Germany
| | - H. Y. Chen
- Institute of Nuclear and Energy Technology, Karlsruhe, Germany
| | - N. I. Tak
- Institute of Nuclear and Energy Technology, Karlsruhe, Germany
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O'Brien WT, Xu G, Batta A, Tint GS, Salen G, Dyer CA, Kendler A, Servatius RJ. Developmental sensitivity of associative learning to cholesterol synthesis inhibitors. Behav Brain Res 2002; 129:141-52. [PMID: 11809505 DOI: 10.1016/s0166-4328(01)00342-4] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Patients with Smith-Lemli-Opitz syndrome, a genetic disorder associated with severe mental retardation, are unable to convert 7-dehydrocholesterol to cholesterol. Treatment of rats with agents that block cholesterol synthesis produces a sterol profile reminiscent of Smith-Lemli-Opitz patients i.e., low levels of cholesterol accompanied by the appearance of its immediate precursor 7-dehydrocholesterol. In previous work, chronic inhibition of cholesterol synthesis in just-weaned rats impaired acquisition of the classically conditioned eyeblink response. The present study had two primary goals--(1) to determine whether the learning impairment depended on the age in which treatment was initiated; and (2) to determine whether the deficit was associative or due to performance factors. Consistent with earlier work, acquisition of the eyeblink conditioned response was impaired when the 30-day treatment was initiated on postnatal day (PND) 21. Reactivity to acoustic stimuli and to eyelid stimulation were normal, suggesting that the learning impairment was associative in nature. The learning impairment was transitory; acquisition was normal when evaluated 30 days after the cessation of treatment. When treatment was initiated 30 days after weaning (PND 51), acquisition of the eyeblink response was normal. However, brain sterols of young adult rats were less affected than those of just-weaned rats. Thus, there is a developmental sensitivity to cholesterol synthesis blocking agents both in terms of their effects on brain sterols and new motor learning.
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Affiliation(s)
- W T O'Brien
- Department of Neurosciences, New Jersey Medical School, Newark, NJ, USA
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65
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Xu G, Salen G, Shneider BL, Ananthanarayanan M, Shefer S, Ma L, Batta A, Nguyen LB, Lingutla JJ, Tint GS, Pcolinsky M, Suchy FJ. Cholecystectomy prevents expansion of the bile acid pool and inhibition of cholesterol 7alpha-hydroxylase in rabbits fed cholesterol. J Lipid Res 2001; 42:1438-43. [PMID: 11518763] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/21/2023] Open
Abstract
To study the effect of cholecystectomy on the regulation of classic and alternative bile acid syntheses, gallbladder-intact (n = 20) and cholecystectomized (n = 20) New Zealand White rabbits were fed either chow or chow with 2% cholesterol (3 g/day). After 10 days, bile fistulas were constructed in half of each rabbit group to recover and measure the bile acid pool and biliary bile acid flux. After cholesterol feeding, the bile acid pool size increased from 268 +/- 55 to 444 +/- 77 mg (P < 0.01) with a 2-fold rise in the biliary bile acid flux in intact rabbits but did not expand the bile acid pool (270 +/- 77 vs. 276 +/- 62 mg), nor did the biliary bile acid flux increase in cholecystectomized rabbits. Ileal apical sodium-dependent bile acid transporter protein increased 46% from 93 +/- 6 to 136 +/- 23 units/mg (P < 0.01) in the intact rabbits but did not change in cholecystectomized rabbits (104 +/- 14 vs. 99 +/- 19 units/mg) after cholesterol feeding. Cholesterol 7alpha-hydroxylase activity was inhibited 59% (P < 0.001) while cholesterol 27-hydroxylase activity rose 83% (P < 0.05) after cholesterol feeding in the intact rabbits but neither enzyme activity changed significantly in cholesterol-fed cholecystectomized rabbits. Fecal bile acid outputs reflecting bile acid synthesis increased significantly in the intact but not in the cholecystectomized rabbits fed cholesterol. Removal of the gallbladder prevented expansion of the bile acid pool after cholesterol feeding as seen in intact rabbits because ileal bile acid transport did not increase. As a result, cholesterol 7alpha-hydroxylase was not inhibited.
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Affiliation(s)
- G Xu
- Medical Service, Veterans Affairs Medical Center, East Orange, NJ 07018-1095, USA
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Baudry K, Swain E, Rahier A, Germann M, Batta A, Rondet S, Mandala S, Henry K, Tint GS, Edlind T, Kurtz M, Nickels JT. The effect of the erg26-1 mutation on the regulation of lipid metabolism in Saccharomyces cerevisiae. J Biol Chem 2001; 276:12702-11. [PMID: 11279045 DOI: 10.1074/jbc.m100274200] [Citation(s) in RCA: 45] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
A temperature-sensitive Saccharomyces cerevisiae mutant harboring a lesion in the ERG26 gene has been isolated. ERG26 encodes 4alpha-carboxysterol-C3 dehydrogenase, one of three enzymatic activities required for the conversion of 4,4-dimethylzymosterol to zymosterol. Gas chromatography/mass spectrometry analyses of sterols in this mutant, designated erg26-1, revealed the aberrant accumulation of a 4-methyl-4-carboxy zymosterol intermediate, as well as a novel 4-carboxysterol. Neutral lipid radiolabeling studies showed that erg26-1 cells also harbored defects in the rate of biosynthesis and steady-state levels of mono-, di-, and triglycerides. Phospholipid radiolabeling studies showed defects in the rate of biosynthesis of both phosphatidic acid and phosphatidylinositol. Biochemical studies revealed that microsomes isolated from erg26-1 cells contained greatly reduced 4alpha-carboxysterol-C3 dehydrogenase activity when compared with microsomes from wild type cells. Previous studies have shown that loss of function mutations in either of the fatty acid elongase genes SUR4/ELO3 or FEN1/GNS1/ELO2 can "bypass" the essentiality of certain ERG genes (Ladeveze, V., Marcireau, C., Delourme, D., and Karst, F. (1993) Lipids 28, 907-912; Silve, S., Leplatois, P., Josse, A., Dupuy, P. H., Lanau, C., Kaghad, M., Dhers, C., Picard, C., Rahier, A., Taton, M., Le Fur, G., Caput, D., Ferrara, P., and Loison, G. (1996) Mol. Cell. Biol. 16, 2719-2727). Studies presented here have shown that this sphingolipid-dependent "bypass" mechanism did not suppress the essential requirement for zymosterol biosynthesis. However, studies aimed at understanding the underlying physiology behind the temperature-sensitive growth defect of erg26-1 cells showed that the addition of several antifungal compounds to the growth media of erg26-1 cells could suppress the temperature-sensitive growth defect. Fluorescence microscopic analysis showed that GFP-Erg26p and GFP-Erg27p fusion proteins were localized to the endoplasmic reticulum. Two-hybrid analysis indicated that Erg25p, Erg26p, and Erg27p, which are required for the biosynthesis of zymosterol, form a complex within the cell.
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Affiliation(s)
- K Baudry
- Department of Biochemistry, MCP Hahnemann University, Philadelphia, Pennsylvania 19129, USA
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Nguyen LB, Xu G, Shefer S, Tint GS, Batta A, Salen G. Comparative regulation of hepatic sterol 27-hydroxylase and cholesterol 7alpha-hydroxylase activities in the rat, guinea pig, and rabbit: effects of cholesterol and bile acids. Metabolism 1999; 48:1542-8. [PMID: 10599986 DOI: 10.1016/s0026-0495(99)90243-3] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
The regulation of the classic and alternative bile acid synthetic pathways by key hepatic enzyme activities (microsomal cholesterol 7alpha-hydroxylase and mitochondrial sterol 27-hydroxylase, respectively) was examined in bile acid depletion and replacement and cholesterol-feeding experiments with rats, guinea pigs, and rabbits. The bile acid pool was depleted by creating a bile fistula (BF) and collecting bile for 2 to 5 days, and it was replaced by intraduodenal infusion of the major biliary bile acids (taurocholic acid [TCA], glycochenodeoxycholic acid [GCDCA], and glycocholic acid [GCA] in the rat, guinea pig, and rabbit, respectively) at rates equivalent to the measured hepatic flux of the bile acids. To study the effects of cholesterol, the animals were fed for 7 days on a basal diet with and without 2% cholesterol. Cholesterol 7alpha-hydroxylase and sterol 27-hydroxylase activities, measured by isotope incorporation assays, were related to bile acid output and composition and hepatic cholesterol concentrations. Intraduodenal infusion of bile acids increased the output of the tested bile acids, but did not significantly change hepatic cholesterol concentrations and had no effect on sterol 27-hydroxylase activity. Neither bile acid depletion nor replacement affected sterol 27-hydroxylase activity when three different substrates (cholesterol, 5beta-cholestane-3alpha,7alpha-diol, and 5beta-cholestane-3alpha,7alpha,12alpha-triol) were tested. In contrast, feeding 2% cholesterol increased hepatic cholesterol concentrations in rats, guinea pigs, and rabbits threefold, twofold, and eightfold, respectively, and increased hepatic mitochondrial sterol 27-hydroxylase activity (conversion of cholesterol to 27-hydroxycholesterol) in all three animal models. The stimulation and feedback inhibition of cholesterol 7alpha-hydroxylase activity by bile acid depletion and replacement were observed in all three animal models, whereas the effect of cholesterol feeding was species-dependent (cholesterol 7alpha-hydroxylase activity increased in the rat, did not change in the guinea pig, and was inhibited in the rabbit). Thus, in contrast to sterol 27-hydroxylase, which was upregulated by cholesterol but not affected by bile acid depletion and replacement in all three animal models, cholesterol 7alpha-hydroxylase activity was controlled consistently and inversely by the hepatic flux of bile acids, but was species-dependent in its response to a 1-week feeding with 2% cholesterol.
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Affiliation(s)
- L B Nguyen
- Department of Medicine/Division of Gastroenterology and the Liver Center, University of Medicine and Dentistry of New Jersey-New Jersey Medical School, Newark 07103, USA
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Shefer S, Salen G, Honda A, Batta A, Hauser S, Tint GS, Honda M, Chen T, Holick MF, Nguyen LB. Rapid identification of Smith-Lemli-Opitz syndrome homozygotes and heterozygotes (carriers) by measurement of deficient 7-dehydrocholesterol-delta 7-reductase activity in fibroblasts. Metabolism 1997; 46:844-50. [PMID: 9225842 DOI: 10.1016/s0026-0495(97)90133-5] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
To extend the enzyme deficiency in Smith-Lemli-Opitz syndrome (SLOS) to extrahepatic tissues, 7-dehydrocholesterol-delta 7-reductase activity was measured in fibroblasts from 10 controls, five SLOS homozygotes, and five obligate heterozygotes. In cells grown almost to confluence in cholesterol-containing medium (4 mg/dL), the conversion of [1,2-3H]7-dehydrocholesterol to cholesterol (7-dehydrocholesterol-delta 7-reductase activity) was 3.8 times higher in control than in homozygote cells and 2.2 times higher than in heterozygote cells. After 24 hours' exposure of the fibroblasts to cholesterol-deficient medium supplemented with lovastatin, 7-dehydrocholesterol-delta 7-reductase activity increased twofold in controls, but did not change significantly in either heterozygous or homozygous cells. In contrast, the activities of 3-hydroxy-3-methylglutaryl coenzyme A (HMG-CoA) reductase and lathosterol 5-dehydrogenase, two key enzymes that precede 7-dehydrocholesterol-delta 7-reductase in the cholesterol biosynthetic pathway, and low-density lipoprotein (LDL) receptor-mediated binding were equal in control, homozygote, and heterozygote fibroblasts. Further, HMG-CoA reductase activity and LDL receptor-mediated binding increased after exposure of the cells to cholesterol-deficient medium. Fibroblast cholesterol concentrations were approximately equal, although homozygote cells contained 30 times more 7-dehydrocholesterol. Thus, markedly reduced 7-dehydrocholesterol-delta 7-reductase activity that cannot be upregulated after exposure of the cells to cholesterol-deficient medium is diagnostic for the biochemical defect in SLOS. Significantly reduced enzyme activity between the levels in controls and homozygotes without accumulation of 7-dehydrocholesterol in fibroblasts identified heterozygotes.
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Affiliation(s)
- S Shefer
- Department of Medicine, University of Medicine and Dentistry (UMD)-New Jersey Medical School, Newark 07103, USA
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Nguyen LB, Shefer S, Salen G, Ness GC, Batta A, Chowdhary IR, Paroulek E, Hauser S. Regulation of 3-hydroxy-3-methylglutaryl-coenzyme A reductase activity in the rat ileum: effects of bile acids and lovastatin. Metabolism 1994; 43:1446-50. [PMID: 7968602 DOI: 10.1016/0026-0495(94)90043-4] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
We investigated the effects of intestinal bile acid flux, orientation of the 7-hydroxy group, and administration of lovastatin on the regulation of intestinal 3-hydroxy-3-methylglutaryl-coenzyme A (HMG-CoA) reductase activity in the rat ileum. HMG-CoA reductase activities in villous and crypt cells from the ileal mucosa were similar, and the study was performed on whole mucosa that contained both cell types. Taurocholate feeding decreased ileal reductase activity 48%, whereas tauroursocholate, the 7 beta-hydroxy epimer of taurocholate, had no effect. Feeding lovastatin (inhibitor of HMG-CoA reductase) stimulated total ileal HMG-CoA reductase activity threefold in washed microsomes, which were dissociated from the inhibitor. However, the proportion of active enzyme in the ileum of lovastatin-fed rats was 50% lower than in controls, whereas there was no change in the percentage of expressed enzyme with bile acid treatments. Interruption of the enterohepatic circulation (bile fistula) increased HMG-CoA reductase activity in the ileum 73%. Duodenal infusion of taurocholate to bile-fistula rats significantly decreased microsomal HMG-CoA reductase activity in the ileal mucosa. In contrast, infusion of the 7 beta-hydroxy epimer tauroursocholate failed to inhibit the derepressed HMG-CoA reductase activity in the ileum of bile-fistula rats. The inhibition of intestinal HMG-CoA reductase activity by taurocholate occurred without accumulation of mucosal cholesterol. Furthermore, the stimulation of total ileal HMG-CoA reductase activity by lovastatin treatment was observed without a decrease in mucosal cholesterol. In summary, the regulation of ileal HMG-CoA reductase activity by the intestinal luminal flux of bile acids is dependent on the orientation of the hydroxyl groups.(ABSTRACT TRUNCATED AT 250 WORDS)
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Affiliation(s)
- L B Nguyen
- Department of Medicine, University of Medicine and Dentistry of New Jersey-New Jersey Medical School, Newark 07103
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Nguyen LB, Shefer S, Salen G, Ness G, Tanaka RD, Packin V, Thomas P, Shore V, Batta A. Purification of cholesterol 7 alpha-hydroxylase from human and rat liver and production of inhibiting polyclonal antibodies. J Biol Chem 1990; 265:4541-6. [PMID: 2106520] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Abstract
Cholesterol 7 alpha-hydroxylase, the cytochrome P-450-dependent and rate-controlling enzyme of bile acid synthesis, was purified from rat and human liver microsomes. The purified fractions were assayed in a reconstituted system containing [4-14C]cholesterol, and cholesterol 7 alpha-hydroxylase activities in these fractions increased 500-600-fold relative to whole microsomes. Polyacrylamide gel electrophoresis of rat microsomes followed by immunoblotting with polyclonal rabbit antisera raised against purified cholesterol 7 alpha-hydroxylases revealed two peaks at molecular masses of 47,000 and 49,000 daltons for both rat and human fractions. Increasing amounts of rabbit anti-rat and anti-human antibodies progressively inhibited rat microsomal cholesterol 7 alpha-hydroxylase activity up to 80%. In contrast, monospecific antibodies raised against other purified cytochrome P-450 enzymes (P-450f, P-450g, and P-450j) did not inhibit rat or human cholesterol 7 alpha-hydroxylase activity. Immunoblots of rat microsomes with the rabbit anti-rat cholesterol 7 alpha-hydroxylase antibody demonstrated that the antibody reacted quantitatively with the rat microsomal enzyme. Microsomes from cholesterol-fed rats showed increased cholesterol 7 alpha-hydroxylase mass, whereas treatment with pravastatin, an inhibitor of hydroxy-methylglutaryl-coenzyme A reductase, reduced enzyme mass. Microsomes from starved rats contained slightly less cholesterol 7 alpha-hydroxylase protein than chow-fed control rats. These results indicate a similarity in molecular mass, structure, and antigenicity between rat and human cholesterol 7 alpha-hydroxylases; demonstrate the production of inhibiting anti-cholesterol 7 alpha-hydroxylase antibodies that can be used to measure the change in cholesterol 7 alpha-hydroxylase enzyme mass under various conditions; and emphasize the unique structure of cholesterol 7 alpha-hydroxylase with respect to other cytochrome P-450-dependent hydroxylases.
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Affiliation(s)
- L B Nguyen
- Department of Medicine, University of Medicine and Dentistry of New Jersey, New Jersey Medical School, Newark 07103
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Nguyen LB, Shefer S, Salen G, Ness G, Tanaka RD, Packin V, Thomas P, Shore V, Batta A. Purification of cholesterol 7 alpha-hydroxylase from human and rat liver and production of inhibiting polyclonal antibodies. J Biol Chem 1990. [DOI: 10.1016/s0021-9258(19)39596-1] [Citation(s) in RCA: 20] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022] Open
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